In 3rd generation dentin bonding agents, HEMA (Hydroxyethylmethacrylate) is
a hydrophilic monomer that wets the dentinal surface
a hydrophilic resin that forms a “hybrid” layer by chemically reacting the intertubular dentin.
a hydrophilic monomer that alters collagen to promote cross linking of collagen to dentin.
a bifunctional molecule resin that copolymerizes to bis-GMA resins.
Correct answer is b. 1,4
Nakabayashi N, Takarada K. Effect of HEMA on bonding to dentin. Dent Mater 1992; 8:125.
Asmussen E, Hansen EK. Dentine bonding agents. In: Vanherle G, Degrange M, Wellems G (eds). STATE OF THE ART ON DIRECT POSTERIOR FILLING MATERIALS AND DENTINE BONDING . Proceedings Of The International Symposium Euro Disney, ed 2. Leuven, Belgium: Ban der Poorten, 1994:33.
Eliades G. Clinical relevance of the formulation and testing of dentine bonding systems. J Dent 1994; 22:73
Nikaido T, Durrow MF, Tagami J, Takatsu T. Effect of pulpal pressure on adhesion of resin composite to dentin: Bovine serum versus salin. Quintessence Int 1995; 26:221
Schwartz RS, Summitt JB, Robbins JW, dos Santos J. Fundamentals of Operative Dentistry, A Contemporary Approach. Page 166. Enamel and Dentin Adhesion.
The objective of this priming step is totransform the hydrophilic dentin surface into a hydrophobic and spongy state that allows the adhesive resin to wet and penetrate the exposed collagen network efficiently.
2-hydroxyethyl methacrylate, described as essential to the promotion of adhesion because of its excellent wetting characteristics, is found in the primers of many modern adhesive systems.
What is the active agent in most home (night guard) bleaching solutions?
2-5% carbamide peroxide
10 - 15% Phosphoric acid
10 - 15% carbamide peroxide
35% hydrogen peroxide
5 - 10% citric acid
15% CARBAMIDE PEROXIDE
15% carbamide peroxide
BRITESMILETM AT HOME
CONTRAST P. M.
10%, 15%, 20% carbamide peroxide
ENCORE HOME WHITENING
10% carbamide peroxide
KAIBAB STARBRITE, INC. HOME BLEACHING SYSTEM STARLITE
10% carbamide peroxide
NITE WHITE CLASSIC
10%, 16%, 22% carbamide peroxide
NITE WHITE EXCEL
10%, 16%, 22% carbamide peroxide
10% carbamide peroxide
10% carbamide peroxide
PLATINUM PORFESSIONAL TOOTH WHITENING SYSTEM
10% carbamide peroxide
REMBRANDT GEL PLUS 10%, 15%, 22%
10%, 15%, 22% carbamide peroxide
TRIO STEP-BLEACHING SYSTEM
11%, 13%, 16% carbamide peroxide
VITINT SYSTEM V
WHITE & BRITE ULTIMATE
11% carbamide peroxide
Which rotary instrument gives the smoothest enamel cut?
carborundum stone (green stone)
aluminum oxide stone (white stone)
plain fissure bur
cross-cut fissure bur
medium diamond bur
Correct answer is c. plain fissure bur
Barkmeier WW, Kelsey WP 3d, Blankenau RJ, Peterson DS, Enamel Cavosurface Bevels Finished With Ultraspeed Instruments. J Prosthet Dent Apr 1983;49(4):481-484.
Rating scores ranked the straight fissure bur first for producing the smoothest and most distinct bevel. The 40-fluted and 12-fluted finishing burs ranked second and third, respectively, and the superfine diamond stone was judged to produce the roughest and least distinct bevel. In selecting an instrument for finishing an external enamel cavosurface bevel, the results of this study suggest that a straight fissure bur will produce the most distinct and smoothest bevel and ultrarotational speeds are used.
The crosss-sut fissure bur is perhaps more efficient, less chatter. The medium diamond bur actually has greatest efficiency but gives the roughest cut.
4. The “biologic width” is the distance between the
A. Base of the gingival sulcus and the crest of alveolar bone
B. Free gingival margin and the base of the gingival sulcus
C. Free gingival margin and the alveolar bone
D. Free gingival margin and the mucogingival junction
E. Free gingival margin and the base of connective tissue attachment
In health, the connective tissue and epithelial attachments occupy the space between the base of the sulcus and the alveolar crest and measure approximately 2.0 mm - this is termed biologic width. Ref. Fundamentals of Operative Dentistry Schwartz, Summit, Robbins and Santos pg. 21.
Biologic width refers to the combined connective tissue and epithelial attachments from the crest of the alveolar bone to the base of the gingival sulcus and is equal to an average of 2.04 mm. Gargiulo et al. Dimensions and relations of the dentogingival junction in humans. J Periodontol 1961:32:261-7.
In calculating the placement of restorative margins, most literature agrees on need for additional 1-2 mm of sound tooth structure coronal to epithelial attachment, therefore, the minimum distance between the alveolar crest and the restorative margin should be 3-4 mm. This allows 1mm for the sulcus. Ref. Clinical Update Vol. 17, No.5.
5. When incrementally placing a large composite resin restoration, what effect does an air-inhibited layer on the surface of the first increment have on the bond between the first and the second increments?
A. It has no effect on the bond
B. It is desirable and improves the bond
C. It is undesirable and should be removed
D. Its presence indicates that the composite requires further light polymerization
E. A layer of unfilled bonding agent should be applied to increase the bond
Incremental placement is possible because of a phenomenon referred to as the air-inhibited layer. Polymerization is initiated and progresses because of free radicals that are formed in the resin monomers. These free radicals are highly reactive to oxygen; when they come in contact with air at the surface of the composite, an unpolymerized air-inhibited layer is formed. The air-inhibited layer is reactive to new composite and forms a cohesive bond to additional increments.
Ref. Fundamentals of Operative Dentistry Schwartz, Summit, Robbins and Santos pg. 21.
Caputo, J. Pros Jann 1989.
6. The powder component of IRM is essentially
A. EBA with methyl methacrylate
B. Zinc oxide with EBA
C. Zinc oxide and aluminum oxide
D. Zinc oxide and methyl methacrylate
E. Zinc oxide and ethyl methacrylate
Powder: Zinc oxide Liquid: Eugenol
Rosin ( brittleness) Olive Oil (plasticizer)
Zinc Stearate (plasticizer)
Zinc Acetate ( strength)
Polymer-reinforced ZOE cement
Powder: Zinc oxide (80%)
Methyl methacrylate (20%) Liquid: Eugenol
EBA-alumina-reinforced ZOE cement
Powder: Zinc oxide (70%) Liquid: ortho-EBA (62.5%)
Alumina (30%) Eugenol (37.5%)
If EBA is added, it is added to the liquid, not the powder.
Methyl methacrylate, not ethyl methacrylate is used.
The choice of zinc oxide and aluminum is debatable. According to Craig, there are some experimental cements that contain 64% zinc oxide and 30% aluminum oxide in the powder and 87.5% EBA and 12.5% n -hexyl vanillate in the liquid.
Ref. Restorative Dental Materials Ninth Edition Craig pg 190.
7. If used, in which direction should pinholes be placed?
a. parallel to the long axis of the tooth
b.parallel to the nearest external surface
c. at a 15 degree angle to the long axis of the tooth
d. perpendicular to the gingival floor
e. directly below and parallel to restored cusp tip
Ref.: FUNDAMENTALS OF OPERATIVE DENTISTRY, Schwartz, Schmitt, Robbins
pp. 273, Fig. 10-32a
“To align a pin channel drill, a non-depth-limiting pin channel drill is aligned
parallel to the external surface.”
8. Optimum penetration of a .024 or .031 inch self-threading pin in dentin is . . .
a. 0.5 mm
b. 1.0 mm
c. 2.0 mm
d. 2.5 mm
e. 3.0 mm
Ref.: FUNDAMENTALS OF OPERATIVE DENTISTRY, Schwartz, Schmitt, Robbins
pp.271, Fig. 10-29b
“Regular (0.031-inch diameter) gold-plated stainless steel Link Plus pin with Regu-
lar (0.027-inch diameter) pin channel drill; Minim (0.024-inch diameter) titanium
alloy Link Plus pin with Minim (0.021-inch diameter) pin channel drill (2.0-mm
9. High content copper amalgam . . .
a. generally requires greater energy to accomplish trituration
b. should be placed rapidly in large increments
c Continues to leak since the corrosion products do not form
d. does not cause galvanism in oral environment
e. is equally effective as conventional alloys in clinical studies
requires greater energy to accomplish trituration. High Cu amalgams 12% to eliminate gamma 2, the ADA standard is 9%
Etching a hybrid glass ionomer-composite
is necessary for composite resin bonding
is not necessary for composite resin bonding
is necessary for adding a glass ionomer cement for repair
is not necessary for adding a glass ionomer cement for repair
a 3-5 second etch with 10% phosphoric acid is recommended
Correct answer is B
It is not necessary to etch the composite for glass ionomer bonding to it.
Class operative notes, Also consult with Capt. Tyler.
In comparing conventional glass ionomer restorative materials with light-curing glass ionomer (resin ionomer) materials, which of the following physical properties of the light cured materials are improved?
bond strength to composite
thermal coefficient of expansion
all of the above
Correct answer is C.
Conventional glass ionomer cements contain the ion-leachable fluoroaluminosilicate glass of the silicate cements but avoid their susceptibility to dissolution by substituting the carboxylic acids from zinc carboxylate cements for phosphoric acids.
The glass is high in aluminum and fluoride, with significant amounts of calcium, sodium and silica. The liquid is typically polyacrylic acid, but may contain polymers and copolymers of polycrylic acid, itaconic, maleic, or vinyl phosphoric acid.
The setting reaction of glass-ionomer cements has been characterized as acid base reaction between the glass powder and the polyacid liquid.
Conventional glass ionomer cements offer several advantages over other restorative materials. They provide long term release of fluoride ions, with cariostatic potential, and inherent adhesion to tooth structure.
Because they posses a coefficient of thermal expansion closely approximating that of tooth structure and a low setting shrinkage , they provide a good marginal seal, little microleakage at restoration-tooth interface, and high retention rate. They are biocompatible have a high retention rate.
Conventional glass ionomers is technically demanding and highly sensitive to changes in the water content. Early moisture contamination disrupts it s surface and removes metallic ions, while desiccation causes shrinkage and crazing. Glass ionomers have a short working time and a long setting time, delayed finishing of the restoration. In addition their physical properties and esthetic potential are inferior to those of resin composites.
Light-cured glass ionomer cements- In his operative text, Summit says that this is a incorrect term for Resin modified glass ionomer cements. He says the more correct term is dual cured, because the original acid-base reaction is supplemented by light activated polymerization. Examples include Vitremere and Fuji I LC
A diverse group of marketed materials has been placed under the term resin-modified glass ionomer cements. The products vary from those that closely resemble conventional glass -ionomer cement to those that approximate light curing resin composites and cure almost exclusively by light initiated polymerization of free radicals. For the latter, no or little water is present in the system to allow the acid-base reaction, typical of glass ionomer cements. A true resin modified glass ionomer cement, then is defined as a two part system, characterized an acid-base reaction critical to its cure, diffusion-based adhesion between tooth surface and the cement, and continuing fluoride release.
Resin modified glass-ionomers are easier to use than conventional glass ionomer cements. The supplementary light polymerization allows a longer working time, a rapid hardening and a more rapid early development of strength and resistance against aqueous attack that are found in conventional glass ionomer cements (solubility).
Mechanical properties, such as compressive , tensile, and flexural strength, fracture toughness, wear resistance, fatigue resistance , bond strength to enamel, dentin, and other resin based restorative materials (composite), marginal adaptation, and microleakage are reported to be improved over the mechanical properties of conventional glass ionomer cements.
They appear to be less sensitive to liquid , are radioopaque, and offer better esthetics possibilities than conventional glass ionomer cements. The fluoride release of resin modified glass ionomer cements is reported to be equal or higher than that of conventional glass ionomer cements and fluoride potential may be rechargeable. However, their physical properties are still inferior to resin composites.
They have a higher thermal coefficient of expansion than conventional glass ionomer, which is not an improvement over conventional glass ionomers.
Reference: Fundamentals of Operative Dentistry. A Contemporary Approach Summit, 1996 page 176-179
The principal reasons for placing a gingival interproximal wedge in conjunction with a matrix for amalgam condensation are to:
separate the teeth slightly
keep the band tight at the gingival margin
contribute to the interproximal contact of the restoration
retract the gingival tissue
all of the above
Correct answer is E.
The wedge separates the teeth slightly ( 90 microns of movement) to compensate for the thickness of the band material.
The wedge is positioned interproximally to secure the band tightly at the gingival margin to prevent access of amalgam (overhang).
The wedging action between the teeth should provide enough separation to compensate for thickness of the matrix band. This will ensure a positive contact relationship after the matrix is removed following the condensation and initial carving of the amalgam.
Wedges can be used to retract gingival tissue.
References: The Art and Science of Operative Dentistry. Studervant, 1994 page 459-465
Fundamentals of Operative Dentistry. A Contemporary Approach. Summit, 1996 page 286
13. In the hand instrument formula, 13-80-8-14, the number 14 represents the
(c. blade angle) .
a. width of the blade
b. blade length
c. blade angle
d. primary cutting edge angle
e. none of the above.
THE BASIC INSTRUMENT FORMULA
The first number of the formula describes the width of the blade in tenths of a millimeter.
The second number describes the length of the blade in millimeters.
The third number describes the angle the blade forms with the axis of the handle. This angle is expressed in “hundredths” of a circle or centigrades.
13 = blade width 1.3 millimeters
8 = blade length in millimeters
14 = blade angled 14 centigrades from axis of handle or shaft
The fourth number
When the cutting edge or face of an instrument is at an angle other than a right angle to the length of the blade, a fourth number is added to the basic 3 number formula. This additional number, expressed in centigrades, represents the angle formed between cutting edge and central axis of the shaft. It is placed in the second position of the formula.
80 = cutting edge angled 80 centigrades from the axis of the handle or shaft
Principles and Practice of OPERATIVE DENTISTRY second edition,
Charbeneau, Cartwright p.146-148
14. Which of the following is NOT a characteristic of glass ionomer cements?
a. strong in compression but weaker in tension (True)
b. the matrix is formed during the initial set of the cement (Initial?)
c. sets via an ion exchange reaction that continues for at least 24 hours (True)
d. suitable for use as a core build up material in anterior teeth (False)
e. all of the above are correct
correct answer is D
a. Silicate is the strongest of the dental cements. When properly mixed the compressive strength is at least 167 Mpa (24,200 psi). As with all cements, it is considerably weaker when tested in tension.
b. initial set?
c. The high initial solubility (24 hour) is attributed to the rather long time required for the setting reaction to go to completion.
d. There are currently 4 widely used core materials, glass ionomer, resin composite, amalgam and cast metal. Conventional GI materials have the advantage of fluoride release, ease of manipulation, natural color, biocompatibility, corrosion resistance and dimensional stability in wet enviornments. Major disadvantage is low fracture toughness, susceptible to propagation of cracks.
Conventional and silver reinforced glass ionomers can only be recommended for use in posterior teeth in which at least 50% of the natural coronal tooth structure remains.
Fundamental of Operative Dentistry, A Contemporary Approach
Science of Dental Materials 8th edition, Phillips p.372
15. Which statements about the dentinal smear layer are TRUE? c. (2, 4, 5)
1. must be removed prior to the application of bonding agents (False)
2. can be produced by high speed, low speed, or hand instrumentation (True)
3. removal has little effect on increasing dentin permeability (False)
4. effectively removed by sequential treatment of sodium hypochlorite and EDT (True)
5. may contain viable microorganisms (True)
a. 1, 2, 5
b. 2, 3, 4
c. 2, 4, 5
d. 1, 3, 5
e. all of the above
1. this layer, approximately 5-10 um is referred to a s the smear layer. Naturally this debris can prevent bonding of dental adhesive cement but is not an essential procedure for bonding.
2. Instrumentation involved in cutting a cavity preparation produces a tenacious layer of debris (smear layer) particularly on the dentin.
3. Unless this film of debris is removed it may interfere with the physical characteristics of some materials or with the quality of their adaptability or adhesion to cavity walls. Optimum behavior of a dental cement, particularly the polyacrylic acid systems, is markedly influenced by the surface cleanliness of tooth structure at the time of placement.
4. Primary consideration in the selection of a cleansing agent is its biological character. It must cleanse without producing irritation to the pulp. Water will cleanse reasonably well.
If water is not adequate, a solution of 2 or 3% Hydrogen Peroxide may be used on a pellet of cotton, then rinsed and dried. Oil from the handpiece or temporary restorative material can be removed effectively by 10 second swabbing of the surfaces with polycarboxylate cement liquid.
5. Historically it was recommended that the dentin be sterilized before placement of any restorative material to destroy residual microorganisms. Infiltration of microorganisms at the tooth restoration interface can produce microbial activity and acid production.
Textbook of Operative Dentistry 3rd Edition
Baum, Phillips, Lund, pages 7, 132
16. When considering visible light cured composites, which of the following statements is incorrect?
A. An air-inhibited layer is present superficially on the composite.
B. The wavelength of the light which affects the initiator is in the range of 450 to 500 nanometers.
C. All other things equal. The light generally penetrates deeper into a small-particle composite than it does into a microfilled composite.
D. B and C
E. All are true
An air inhibited layer is in fact present on all composite. The oxygen eats up all the free radicals giving soft poorly cured surface layers. Ref. Lecture notes from dental materials.
The wave length that activates the initiator (Camphoquinone) is 450-500 nm. Ref. Lecture notes from dental materials.
The light does penetrate deeper into small particle fills than microfills. The smaller particles absorb more light. Ref. Adept Vol. 2 No. 4 Fall 1991.
17. The clinical advantage of porcelain laminate veneers over composite resin veneers is:
A. Color stability and resistance to abrasion
B. Availability of self-curing or light activated placement
C. Minimal over-contouring of the treated teeth
D. May be used in edge to edge occlusion or Class III relationships.
Color stability and resistance to abrasion - Porcelain is harder than composite and therefore more abrasion resistant. Since the porcelain has no tertiary amines which is the component of composite that discolors it is more color stable. The only color shift in porcelain is form wearing of the external staining. It can be difficult to get the correct color but once cemented they are color stable.
Available of self curing or light activated placement - Yes they are available but so what. It lets you use the porcelain in more areas but I could not call it an advantage over composite.
Minimal overcontouring of the treated teeth - Not necessarily true. Porcelain may be over contoured because of under reduction by the dentist.
May be used in edge to edge relationships or class III relationships. These are contraindications for porcelain veneers. These areas are more likely to fracture because porcelain is not strong in sheer. Listed as a contraindication in the Air Force handout on veneers which references Clark’s Clinical Dentistry, Vol. 4, Chapter 22a, 1990.
18. The ductility of metal is usually expressed in terms of the:
A. Yield strength
B. Per cent elongation
C. Modulus of elasticity
D. Ultimate tensile strength
E. Young’s modulus
Yield strength - The point where the material is no longer elastic.
Percent elongation - The ratio of the increase in length of a material after it is fractured under a tensile load to its length before loading. The most common way of measuring ductility.
Modulus of elasticity - The stiffness of a material. The slope of the stress strain curve.
Ultimate tensile strength - The point on the strength strain curve where the material breaks.
Young’s modulus - Same as Yield strength
Ductility is defined as the ability of a material to withstand permanent deformation under a load with out rupture. .A material that can be drawn in to a wire is said to be ductile.
Reference - Skinner and Phillips 1991 and class notes.
19. In conservative Class II preparations, the likelihood of an amalgam fracture
(isthmus fracture) may be reduced by
a. beveling or rounding the axiopulpal line angles
b. providing undercuts in the occlusal portion of the cavity preparation
c. providing a rounded pulpal floor
d. increasing the faciolingual dimension of the cavity preparation
e. by using a cavity liner prior to placing the amalgam
B. These are for retention of alloy.
C. Reduces stress in alloy to help in alleviating fractures of cuspal walls.
D. Actually can lead to fracture of the tooth or alloy if too much.
E. Cavity liner only used for microleakage during initial set.
Answer: a. The beveling or rounding of the axiopulpal line angles increase the
resistance form of the alloy thus reducing isthmus fracture.
Reference: p 116 fig 7.5 Pickard’s Manual of Operative Dentistry
20. Which of the following would BEST achieve marginal exposure and hemorrhage control after preparation of a Class V cavity located 3mm below the gingival margin?
a. application of retraction cord impregnated with 8% racemic epinephrine
b. application of retraction cord impregnated with 8% zinc chloride solution
c. application of retraction cord impregnated with ferrous sulfate
d. infiltration with local anesthetic containing a vasoconstrictor
e. do a mini-flap procedure and retract the tissue with a rubber dam and retainer to allow placement of the restoration
A. B. C. D. Are all obviously wrong. Predictably achieving hemostasis and adequate marginal exposure to restore a class V cavity prep which extends 3 mm subgingivally would be virtually impossible when using solely retraction cord or anesthetic alone.
E. Is the obvious answer. Perio and Capt Tyler would be proud of us!!
Reference: p 314 Fundamentals of Operative Dentistry
21. When comparing zinc polycarboxylate to zinc phosphate cement, the zinc polycarboxylates
1. have less compressive strength
2. have the same tensile strengths
3. bonds to tooth structure
4. is less irritating to the pulp
a. 1, 2
b. 1, 2, 3
c. 1, 3, 4
d. 2, 3, 4
e. all of the above
2. True (and False p.183 and p 206 from Craig’s Restorative Dental Materials)
Therefore: e. All of the above is the correct answer
Reference: Skinner/Phillips and Craig’s Restorative Dental Materials
22. “Post carve burnishing of amalgam will
a. bring gamma-2 to the surface
b. decrease microporosity
c. force unreacted particles closer together to minimize residual mercury
d. work harden the amalgam
e. eliminate the need to polish the restoration
Gamma-2 is Sn8Hg component--the weakest and most susceptible to corrosion and marginal breakdown--of the low copper alloy. Burnishing has no effect on exuding tin-mercury from the alloy. Baum, 1995. No word on decreasing microporosities. Voids can exist due to insufficient condensation but burnishing in a precarve state has only minimal effect due to the depth/bulk of material. In the post carve phase, burnishing has only a surface effect and will not decrease any microporosities/voids in the amalgam. Two types of burnishing are advocated. The first is “Pre-carve Burnishing” which is a form of condensation and is done when the amalgam is overpacked. Ideally, a burnisher is large enough to reach between the cusp slopes but too large to touch the margins. Precarve achieves denser amalgam at the margins when using high copper amalgams. “Post-carve Burnishing “ is the light rubbing of carved surfaces to achieve a satin but not shiny surface. Post-carve achieves denser amalgam at the margins when using low copper amalgams. Therefore, for conventional low-copper amalgams, doing both a pre and post-burnishing serves as a substitute for conventional polishing. Sturdevant, 3rd ed. 1995 p. 419-20.
23. Proximal root surface caries on posterior teeth
a. are easily detected clinically and radiographically
b. are usually seen in patients under the age of 40
c. may be treated conservatively with a faciolingual type slot
d. usually require electrosurgery for clinical access
e. generally render the tooth non-restorable
The key here is access. Burnout can mask as caries radiographically making detection difficult so ( a. ) is out. Root caries occurs in more patients over age 40 related to gingival recession. Electrosurgery is case specific and depends on pocket depth, amount of attached gingiva, location of the lesion, etc. A miniflap may be more prudent. Root caries can certainly render a tooth non-restorable. So what’s your point? The answer according to the man, Sturdevant, is c. See page 450. Text, 1995 3rd edition under “slot prep for root caries”. He gives 6 paragraphs on technique.
24. The proximal outline of a conservative Class II amalgam preparation is dictated by:
1. location of the caries
2. anatomy of the adjacent tooth
3. amount of demineralized/unsupported enamel present
4. extension for prevention
a. 1, 2
b. 1, 4
c. 1, 2, 3
d. 1, 3, 4
e. all of the above
Schwartz, RS, Summitt, JB and Robbins, JW. Fundamentals of Operative Dentistry: A Contemporary Approach, Quintessence Books, 1996, page 258.
Tooth preparation necessitated by a carious lesion on a proximal surface should, when possible, avoid extension more than is necessary to allow for access to proximal caries (#1) to remove demineralized enamel (#3) and to remove enamel not supported by sound dentin (#3). The proximal surface margins of a Class II amalgam should not be in contact with the adjacent tooth. If to eliminate contact with the adjacent tooth, a significant amount of sound tooth enamel that is supported by sound dentin would have to be cut away, consideration should be given to allowing contact to remain to avoid widening the preparation simply to break contact with the adjacent tooth. (#2)
(#4) is not a factor and is no longer a valid concept. “Prevention of extension” or, as Sigurjons states, “Constriction with Conviction” are the operative phrases in modern cavity preparation.
ref.: Sigurjons, H., “Extension for Prevention: Historical development and current status of G.V. Black’s concepts”’ Oper Dent 8 (2), 1993.
25. When place into sound dentin, a self-threading pin will
1. increase the retention of an amalgam restoration
2. decrease the tensile strength of an amalgam restoration
3. produce less internal stress than a cemented pin
4. produce more internal stress than a cemented pin
a. 1, 2
b. 1, 3
c. 1, 4
d. 1, 2, 3
e. 1, 2, 4
Schartz, R.S., Summitt, J.B. and Robbins, J.W. Fundamentals of Operative Dentistry, A Contemporary Approach. Quintessence Books, 1996 pp. 270.
Study by Dilts and coworkers, self-threading pins were found to be more retentive in dentin than cemented of friction-locked pins.
Standlee, JP, Collard EW Caputo AA. Dentinal defects caused by some twist drills and retentive pins. J Prosthetic Dentistry 1970; 24:185-92.
Threaded pins of the same diameter and the same depth as those of the cemented pins possessed approximately three times greater retention. ( 1 )
“Pins weaken amalgam alloy” (2)
Lecture notes from Dr. Tyler and Schartz, RS, Summitt, JB and Robbins, JW Fundamentals of Operative Dentistry, A Contemporary Approach. Quintessence Books, 1996 pp. 270-274.
Caputo AA, Standlee JP, collard EW. The mechanism of load transfer by retentive pins. J Prosthetic Dentistry 1973;29;442-9.
Friction-lock pins were shown to generate primarily lateral stress, self-threading pins caused primarily apical stresses and no significant stresses were associated with installation of cemented pins. (3,4)
26. Location of the gingival finish lines in crown preparations are influenced by
1. existing restorations
2. crown length available
3. oral hygiene practices
4. periodontal considerations
Crown margins should be apical to other restorative margins on the tooth.
Crown length does influence the placement of crown margins. The longer the crown length the more retentive the crown all other factors remaining equal. So with a short crown you may need a more apical margin than you would on a long tooth.
Nothing directly in the books about this but since the subgingival margin is harder to clean than a supragingival. A patient with substandard oral hygiene practices would be able to clean supragingival easier. So if the option was available you would choose supragingival. You may ask why are you placing gold in a patient that can not clean his teeth - good question but this is pros and they don't seem to worry about that sometimes. Another scenario is a patient that abrades the cervical of his teeth with a toothbrush. A crown margin that covered that area would be indicated.
Periodontal considerations, especially the biologic width, do influence margin placement. Encroaching on the 2 mm biologic width (Gargulio) is contraindicated.
The answer is ALL OF THE ABOVE.
Reference Contemporary Fixed Prosthodontics 1988 Pg. 120.
27. A nonridgid connector:
1. prevents the middle abutment from acting as a fulcrum
2. shouldn't be used in long span fixed partial dentures because teeth can move under normal function.
3. allows different segments of the fixed partial denture to move in different directions
4. allows fixed partial dentures to be made on teeth with different angulation
The nonridgid connector does in fact prevent the abutment from actincg as a fulcrum.
The fact that the teeth move in normal function is the reason that you need a nonridgid connecter.
Moving in different directons sounds weird but is mentioned in Schillenberg.
Teeth of different angulations area prime indication for nonridgid connectors.
Answer B 1,3,4 are correct.
Referance: Shillenberg second edition Pg. 25-29
28. Which of the following are qualities of the tissue-side surface of a properly designed pontic?
1. smooth surface
2. highly polished porcelain
3. minimal tissue contact
4. concave surface
A smooth surface of either highly polished gold or glazed porcelain are the best choices for the tissue contacting area of the pontics. I am assuming that this is a trick question and highly polished does not equal a glazed surface. The book specifies that glazed porcelain should be used.
Minimal tissue contact is desirable as it makes it easier to clean and there is less area to become inflamed.
Concave surface is incorrect the proper surface is convex so there are no inaccessible areas for plaque to hide. What happens when you glaze porcelain? You get sintering at 960º -1000º C with no vacuum. Overglazing causes increased porosity and microfracture of the porcelain. Lower fusing porcelain is used for shoulder
The answer is B.# s 1,3 are correct.
Referance Contemporary Fixed Prosthodontics 1988 Pg. 321
29. Aluminous Porcelain developed by Mclean and Hughes in 1965 is composed of a mixture of low fusing powdered glass and a powdered aluminum oxide (alumina). Its principal use is in the construction of newer porcelain jacket crowns or special jacket -like crowns of porcelain fused to an oxidized tin-plated platinum foil. This foil remains in place as an integral part of the restoration. The technique can produce a cosmetic crown that resembles the classic porcelain jacket, but has greater strength. Alumina is partly soluble in low fusing glass, and its presence strengthens the glass, making it less sensitive to crystallization, and elevating its fusion temperature. Aluminous Porcelain is fired at temperatures up to 200 F (110C) higher than bake-on porcelains and are usually held at maximum temperature for several minutes to allow for densification. They are less susceptible to overfiring and loss of contour than are bake-on porcelains. Aluminous porcelain kits contain opaque body and modifying porcelain powders, which are analogous in purpose to other low-firing porcelains. Rhoads, 1986.
Aluminous porcelain (In-Ceram™)
has twice the compressive strength of feldspathic (& 2.5 X the flexural strength)
has a coefficient of thermal expansion that is comparable to that of glass ceramics p. 505 Skinner, 1982.
has improved strength, which makes it an excellent material for posterior crowns.
Fracture resistance is comparable to metal ceramic restorations. p. 436 Schilling burg
has shown some clinical failures due to cracks originating on the outside surface of the crown
Once found true with early PJC's--pre1965-- but not since nor with In-Ceram--p. 436 Schillingburg--"In evaluating fracture toughness and hardness, alumina was the most effective reinforcing agent". Best w/single unit, but 3unit is max! Alumina has a > modulus of elasticity than feldspathic (quartz)
all of the above
30. The occlusal records used for the functionally generated path technique represent
the movement of the condyles
a "Gothic arch" or arrow point design made by the excursions of a maxillary stamp cusp
the pathways of the opposing cusps within the border movements of the mandible
vertical closure in the intercuspal position
the pathways of the cusps to be restored
The functionally generated path technique is a method of creating occlusal morphology that is shaped by all of the determinants of mandibular movement. The functionally generated path technique employs the use of a tracing made in the mouth to capture pathways traveled by the opposing cusps in mandibular function. Wax is adapted over the occlusal surface of the prepared tooth. The patient occludes the teeth in an intercuspal position and moves the mandible through all excursions. The cusp tips of the opposing teeth carve a recording of the border movements in all mandibular positions. Stone is brushed and poured onto the wax record in the mouth to produce a functional core. The stone core is then utilized in the fabrication of posterior tooth restorations. The prerequisite for the use of this technique for the ideal restoration of a single tooth is the presence of optimal occlusion. The technique perpetuates existing occlusion. Correct anterior guidance must be present with no posterior interferences. p. 355 Schillingburg 3rd ed. 1997.
31. Which of the following has no effect on increasing resistance form of a preparation?
increasing parallelism -both retention and resistance;
one path of draw; decreasd oblique forces
increasing occlusal-gingival length -both retention and resistance; increase surface area; decrease tipping
greater eccentricity of the tooth -anti-rotational
greater circumference of the tooth -increase arc of displacement
all have an effect
Retention (improved by ideally limiting to one path of draw) prevents removal of the restoration along the path of insertion. Resistance prevents dislodgement under occlusal forces-both apical and oblique. As with retention, preparation and geometry play a key role in resistance form. Adequate resistance depends on (1) Magnitude and direction of the dislodging forces (2) Geometry of the tooth preparation (3) Physical properties of the luting agent. As you can imagine, horizontal and oblique forces are much greater (especially in eccentric contact in posterior teeth) than the forces needed to overcome retention.
The tooth preparation must be so shaped that particular areas of the axial wall will prevent rotation of the crown. Hegdahl and Silness analyzed this and demonstrated that increased taper and rounding of axial angles & short tooth preparations with large diameters tend to reduce resistance. Resistance is increased with boxes and grooves and will be greatest if the walls are perpendicular to the direction of the applied force. Grooves provide an anti-rotational feature and thus provide an additional area for luting agent compression. U-shaped grooves are better than V- shaped. Retention and resistance are interrelated and share inseparable qualities. p. 199-22 Schillingburg 3rd ed. 1997; p. 355 Rosenstiel, 2nd ed. '95
32. When mounting diagnostic casts, the use of a face bow transfer will
A. POSITION THE MAXILLARY CAST IN ITS PROPER LOCATION ANTERIOPOSTERIORLY AND MEDIOLATERALLY ON THE ARTICULATOR
b. verify centric relation
c. place the condyles in their most anterior-superior position against the articular eminences
d. verify protrusive relation
e. record the correct musculoskeletal relationship
Shillingburg, HT, Hobo, S, Whitsett, LD, Jacobi, R, Brackett, SE Fundamentals of fixed Prosthodontics 3rd Edition. Pg 29-30.
The facebow is an instrument that records thsoe spatial relationships and is then used for the attacment of the maxillary casts to the articulator. ...used to mount the maxillary cast on the articulator
33. In order to maintain periodontal health, the most ideal position for the gingival margin of a cast gold restoration is
a. just below the crest of the free gingiva
b. at the level of the junctional epithelium
C. ABOVE THE CREST OF THE FREE GINGIVA
d. in the gingival sulcus between the crest and the epithelial attachment
e. 1 mm into gingival sulcus
Shillingburg, HT, Hobo, S, Whitsett, LD, Jacobi, R, Brackett, SE Fundamentals of fixed Prosthodontics 3rd Edition. Pg 132-133.
The best results can be expected from margins that are as smooth as possible and are fully exposed to a cleansing action. ...the finish line should be placed in an area where the margins of the restoration can finished by the dentist and kept clean by the patient. The practice of routinely placing margins subgingivally is no longer acceptable. ...it’s recommended to place the margin supragingival whenever possible. ...subgingival margins are likely to cause gingival inflammation.
34. When using zinc phosphate cement as a luting agent, it is recommended that you
mix quickly on a cold glass slab
MIX SLOWLY OVER A LARGE AREA OF THE GLASS SLAB
PLACE CAVITY VARNISH ON THE TOOTH PRIOR TO CEMENTATION
use when insolubility is a desired property
Shillingburg, HT, Hobo, S, Whitsett, LD, Jacobi, R, Brackett, SE Fundamentals of fixed Prosthodontics 3rd Edition. Pg 406-409.
Partial protection of the pulp can be provided by the application of two thin layers of copal cavity varnish. This patially seals the dentinal tubules and protects the pulp from the phosphoric acid.
Cement is mixed with a circular motion over a wide area. ...glass slap...cooled in tap water and wiped dry. ...must be mixed slowly over a wide area on a cool glass slab to insure that a maximum amount of powder can be incorporated into a mix...
35. Which of the following types of maxillary cantilevered fixed partial dentures would be most destructive to the periodontal supporting tissues of the abutment tooth?
Molar abutment, premolar pontic
B. Canine abutment, lateral incisor pontic
C. Lateral incisor abutment, central incisor pontic
D. Central incisor abutment, central incisor pontic
E. Central incisor abutment, lateral incisor pontic
“Ante’s Law” (Johnston et al): The root surface area of the abutment teeth have to equal or surpass that of the teeth being replaced with pontics.
Ref. Shillingburg, H et al. Fundamentals of Fixed Prosthodontics Third Edition. 89-93, 1997.
36. When a tooth has adequate attached gingiva, which of the following factors is most likely to contribute to gingival recession when a tooth is restored with a ceramometal crown?
A. Overcontouring the facial surface of the crown
B. Impingement of a temporary crown on the gingival attachment for a period of two weeks
C. Using retraction cord containing epinephrine
D. Placing the margin at the epithelial attachment --infringement of biologic width
E. Creating an inadequate proximal contact
Waerhaug: all subgingival margins create pathology
Newcomb: depth of margin related to severity of inflammation
Valderhaug: 30% subgingival margins had recession
Ref. Waerhaug J: Histo considerations which govern where margins of restorations should be located in relation to gingiva. Dent Clin North Am. P161, 1960.
Newcomb GM: The relationship between the location of subgingival crown margins and gingival inflammation. J Periodontol. 45:151, 1974.
Valderhaug J and Birkland: Periodontal conditions in patients 5 years following insertion of fixed prostheses. J Oral Rehabil. 3:237, 1976.
Overcontouring of the crown will provide for a plaque trap. Local factors can cause gingival recession but it is not the most likely contributor compared to other choices.
An assumption is being made that gingival attachment is referring to the entire attachment apparatus (CT attachment + junctional epithelium), whereas the epithelial attachment is referring to the junctional epithelium only. Therefore, impingement on the gingival attachment could implicate injury as far down as the CT attachment. This is more destructive and more invasive of the biologic width than involving just the epithelial attachment.
Placement of retraction cord can cause recession if not used judiciously. The fact that it contains epinephrine doesn’t increase chances of causing recession.
An open contact with concomitant food impaction can cause gingival recession.
** Per conversation with CAPT Horning: They can all cause gingival recession, however, “B” is the better choice compared to other answers.
37. Group function occlusion is most acceptable for
A. A young person with steep cuspal inclines in the posterior teeth
B. A patient whose cuspid is worn and shows no evidence of traumatic occlusion
C. A patient wearing a posterior maxillary free end saddle RPD that does not include the cuspid as an abutment
D. A patient that has experienced mobility in the maxillary premolars due to excursive contacts
E. A patient with a deep overbite, thus preventing anterior teeth contacting in lateral excursions
Group function (also known as unilateral balanced occlusion) had its origin in the work of Schuyler et al who began to observe the destructive nature of tooth contact on the nonworking side (best to eliminate all tooth contact on the nonworking side).
Unilateral balance occlusion calls for all teeth on the working side to be in contact during lateral excursion AND teeth on the nonworking side are to be free of contact.
The group function of the teeth on the working side distributes the occlusal load.
The absence of contact on the nonworking side prevents those teeth from being subjected to the destructive, obliquely directed forces found in nonworking interferences.
A. The anatomic determinants of mandibular movement, condylar and anterior guidance, have a strong influence on the occlusal morphology of teeth being restored. Steep cusps in posterior teeth will require disclusion by anterior teeth (canines) - anterior guidance.
C. Want canine guidance for a distal extension RPD so that lateral forces are taken off RPD, allowing denture bases to be more stable and minimizing detrimental oblique forces on tissue bearing areas.
D. Group function will only exacerbate the lateral forces in excursive movements. Want to eliminate excursive contacts on mobile teeth.
E. If there is too much vertical overlap, the anterior teeth will disclude posteriors. This does not allow for group function. In group function, you want all the teeth on one side to contact in lateral excursion.
Ref. Ref. Shillingburg, H et al. Fundamentals of Fixed Prosthodontics Third Edition. 11-24, 1997
Lecture notes from occlusion class
38. In an ideal ( Class I ) cusp-fossa relationship, the mesiolingual cusp of the maxillary first molar occludes with the
a. Distal fossa of the mandibular second premolar (thus a SEVERE class II)
b. Mesial fossa of the mandibular second molar ( thus a class III bite)
c. Central fossa of the mandibular first molar (correct answer)
d. Distal fossa of the mandibular first molar (thus a class III bite)
e. Mesial fossa of the mandibular first molar (thus a class II bite)
most occlusion books should agree with this
39. The most common error in preparing as anterior tooth for a ceramometal crown is
a. Insufficient facial reduction (Shillingberg p. 143, Rosentiel p. 185 )
b. Insufficient lingual reduction (could cause problems with excursive movements)
c. Insufficient proximal reduction (could cause problems with emergence profiles)
d. Insufficient incisal reduction (cause problems with incisal coloration and porcelain fracture)
e. Improper placement of the margin (a possible answer if it is placed unesthetically or cord packed improperly)
When performing crown lengthening surgery, the dentist should insure that the distance between the anticipated margin of the restoration and the alveolar crest be no less than
a. 2 mm on the interproximal surfaces (not enough for biological width)
b. 3 mm on the buccal and lingual surfaces ( sounds good but what about the interproximals?)
c. 3 mm on the interproximal surfaces (sounds good but forgot the buccal/lingual)
d. 1 mm on all surfaces ( no biological width here either)
e. 3 mm on all surfaces ( Gargiulo and the theory of biological width: 1 mm for connective tissue attachment, 1 mm for junctional epithelium, 1 mm for sulcus)
Which of the following cements is most sensitive to moisture contamination?
a. glass ionomer
b. zinc phosphate
e. zinc oxide
The glass ionomer cement are very sensitive to contact with water during setting. The field must be isolated completely. Once the cement has achieved initial set (about 7 minutes), the cement margins should be coated with coating agent supplied with the cement.
Water contamination of Zinc Phosphate cement will increase film thickness, solubility, and initial activity.
Water contamination of Zinc Phosphate cement will decrease compressive strength and shorten setting time.
REF: Craig , Restorative Dental Materials, Ninth Ed. 1997 pg 181, 193.
A mutually protected (canine protected ) occlusion should be achieved when restoring the natural dentition of a patient who has which of the following occlusal relationships?
Class III occlusal scheme
Class I occlussal scheme
Class II Division I occlusal scheme
Class II Division II occlusal scheme
Mutually protected occlusion is also known as canine protected occlusion or “organic occlusion. According to this concept of occlusion, the anterior teeth bear all of the load and the posterior teeth are disoccluded in any excursive position of the mandible. The desired result is an absence of frictional wear.
The position of maximum intercuspation coincides with the optimal condylar position of the mandible. All posterior teeth are in contact with the forces being directed along their long axes. The anterior teeth either in contact lightly or are very slightly out of contact, relieving them of the obliquely directed forces that would be the result of anterior tooth contact. As a result of the anterior teeth contact protecting the posterior teeth in all mandibular excursions and the posterior teeth protecting the anterior teeth at the intercuspal position, this type of occlusion became known as a mutually protected occlusion. This arrangement of the occlusion is probably the most widely accepted because of its ease of fabrication and greater tolerance by patients.
In order to reconstruct a mouth with mutually protected occlusion, it is necessary to have anterior teeth that are periodontally healthy. In the presence of anterior bone loss or missing canines, the mouth should probably be restored to group function (unilateral balance). The added support of the posterior teeth on the working side will distribute the load that the anterior teeth may not be able to bear.
The use of mutually protected occlusion is dependent upon the orthodontic relationship of opposing arches. In either a Class II or Class III malocclusion (Angle), the mandible cannot be guided by the anterior teeth. A mutually protected occlusion cannot be used in the situation of reverse occlusion, or cross bite, in which the maxillary and mandibular buccal cusps interfere with each other in a working side excursion.
REF. Shillingburg H. T et al. Fundamentals of Fixed Prosthodontics 3rd Ed., Quintessence 1997, p 19-20.
Which of the following are primary reasons for splinting teeth with a fixed prosthesis?
to stabilize loose teeth in a favorable occlusal relationship
to distribute occlusal forces so periodontically weakened teeth do not loosen
to prevent a natural unopposed tooth from migrating
to prevent maxillary central incisors from separating after closure of diastema
all of the above
Splinting is done for three reasons
To protect loose teeth from injury while stabilizing them in a favorable occlussal relationship.
To distribute occlusal forces so that teeth weakened by loss of periodontal support do not become loose.
To prevent a natural opposed tooth from becoming loose and migrating.
REF. Tylman, S. et al. Tylmans Theory and practice of Fixed Prosthodontics 7th Ed. , Mosby 1978, p 81.
Singer, B. A. Intracoronal Esthetic Splinting, Compendium Vol. 17 No.5, May 1996 pp458-468.
44. Most semi-adjustable articulators reproduce with relative accuracy the
1. direction and end point of some condylar movements
2. intermediate track of some condylar movements
3. Bennett side shift
4. tooth arc of closure
a. 1, 2
b. 2, 3
c. 3, 4
d. 1, 4
e. 1, 2, 4
The semiadjustable articulator reproduces the direction and endpoint, but not the intermediate track of some condylar movements. The inclination of the condylar path is reproduced as a straight line on many articulators, when it fact it usually transverses a curved path. On many instruments, the lateral translation, or Bennett movement, is reproduced as a gradually deviating straight line, although several recently introduced semiadjustable articulators d o accommodate the immediate lateral translation.
A semi adjustable articulator is an instrument whose larger size allows a close approximation to the anatomic distance between the axis of rotation and the teeth. If casts are mounted with a facebow using no more than an approximate transverse horizontal axis, the radius of movement produces on the articulator will reproduce the tooth closure arc with relative accuracy, and any resulting error will be slight.
Shillingburg, Herbert T. Fundamentals of Fixed Prosthodontics., 3rd Edition. 1997, p 25.
Lecture notes from Occlusion Seminar and class notes with Capt. Maxwell.
45. Electrosurgery for crown lengthening is contraindicated in
1. an inadequate zone of attached gingiva
2. a fibrous hyperplastic gingiva with pseudopocketing
3. patients who have had radiotherapy of the head and neck region
4. patients with cardiac pacemakers without coaxial shielding
a. 1, 2, 3
b. 2, 3, 4
c. 1, 3, 4
d. 1, 3
e. 2, 4
If the band of attached gingiva is too narrow, it must be made wider with a graft or an alternative restoration must be made for the tooth. Crown lengthening is contraindicated when there is an inadequate zone o f attached gingiva surrounding the tooth. ( Shillingberg, Fundamentals of Fixed Prosthodontics. 3rd Edition, 1997, p269.
Electro surgery has been described for the removal of irritated tissue that has proliferated over the preparation finish lines, and is commonly used for that purpose. ( Patel MG: Electrosurgical management of hyperplastic tissue. J Prosthet Dent 1986; 56: 145-147.)
For reasons of safety, electrosurgery should not be employed on patients with cardiac pacemakers. External electromagnetic interference hinders the pacemakers function. Electrosurgery will alter the normal function of a pacemaker, and it presents a hazard to the patient who wears one. Shielding in recent pacemaker models diminishes the risks from extraneous electromagnetic interference. But the use of electrosurgery is still contraindicated for those patients who wear pacemakers. ( Shillingberg, Fundamantals of Fixed Prosthondontics. 3rd Edition, 1997, p. 277. Stamps, JT, Muth ER : Reducing accidents and injuries in the dental environment. Dent Clin North Am 198; 22: 389-401.
46. Repair of ceramic materials is
1. A temporary solution
2. best accomplished with microabrasion and the use of hydrofluoric acid to etch the
3. best accomplished without a silane coupling as long as the surface is sandblasted
4. a complicated procedure that usually involves bonding to different surfaces.
a. 1, 4
b. 2, 3
c. 1, 3, 4
d. 1, 2, 4
e. all of the above
Porcelain repair relies on several types of retention: chemical (silane), micromechanical, macromechanical and metal adhesion. There are several available systems. Ceramic repair is usually done by etching the porcelain with either hydrofluoric or phosphoric acid for a presribed time, only after air abrading both the metal with 50 micron aluminum oxide. Apply a silane liquid to the etched porcelain for 2 minutes, and then a low viscosity dentin bonding agent and opaquers to the silanated porcelain and the metal. Apply an unfilled bonding agent and hybrid composite resin and adjust the occlusion to minimize contact in excursive movements. I t is a temporary solution and complicated, involving the bonding of several different surfaces. Each product has very specific steps that have to be followed. It behooves the operator to save the instructions .
The term best acomplished is somewhat misleading and nebulous. There are systems which are etch -free and there are systems which do not use HF acid. I could not find evidence to support the statement that any one method was the best procedure. So I guess I’m waffling just a bit, maybe the answer is d. 1, 2, 4 BUT maybe the BEST answer is a. 1,4.
47. The most important dimension to select when matching colors for teeth to receive ceramic restorations is -
e. Metameric compensation
“It is better to select a compromise shade that looks reasonably good under all three types of light
than to choose one that may look near perfect in sunlight, for example, but appear to be badly mis-
matched in the patient’s home or office.” Shillingburg,Hobo,Whitset,Jacobi & Brackett / Fundamentals
of Fixed Prosthodontics, 3rd ed. 1997, pg. 426.
Chroma = strength of a hue
Hue = name of a color
Value = brightness
Saturation = intensity, however this word relates to chroma, i.e. “how blue is the blue ?”
Metameric compensation is the correct answer here. All of the other terms above relate to the shade
of a particular tooth, their descriptive characteristics, but it all means little if it, taken in the whole field of view, looks grossly out of place.
48. Which of the following anatomic determinants of mandibular movement requires a shorter cusp height during fabrication of a fixed prosthesis?
1. Minimum anterior vertical overlap
2. Minimum anterior horizontal overlap
3. Shallow protrusive condylar inclination
4. Increase in the intercondylar width
a. 1, 3
b. 2, 4
c. 1, 2, 3
d. 2, 3, 4
e. All of the above
During fabrication of a fixed prosthesis, cusp height is a primary consideration. In addition, cusp slope
and fossa size are intimately related to CR - MI slide and Immediate and Progressive Side Shift (ISS)
movements. “The intercuspal position contacts are correlated with a specific excursive guidance.”
“The condyles can reach any position in the joint compartment without guidance from the teeth.”
“Post-insertion goals of a restoration are the following:
1. Maintain an appropriate intercuspal position.
2. Provide a joint-tooth stabilization of the mandible in intercuspal position and retruded contact position.
3. Avoid unilateral retrusive interferences.
4. Avoid mediotrusive interferences.
5. Not restrict intercuspal position for eccentric contact movements.
6. Not curtail condylar movement against the articular eminence. “
Malone,Koth,Cavazos,Kaiser & Morgano, Tylman’s THEORY and PRACTICE of FIXED PROSTHO-
DONYICS, 8th ed., 1989, pg. 336
Anterior determinants of mandibular movement include anterior vertical and horizontal overlap. These
need to be respected when considering posterior cusp height. Cusp heights other than shallow would be contraindicated with a minimum vertical or horizontal overlap. Posterior determinants of mandibular movement include condyle-to-fossa relationships. A shallow angle mesial wall of the glenoid fossa
dictates that posterior tooth cusp height be of similar configuration. Increased intercondylar width means a longer arc is functioning than a shorter intercondylar width. As a result, the buccal and lingual
slopes of the posterior cusps must be accordingly accomodating to this longer arc function in lateral disclusions. The answer is e .
49. A fixed partial denture is to be constructed for the mandibular arch of a 35 year-old female. The opposing permanent maxillary first molar is extruded 3mm beyond the plane of occlusion. The best way to correct this situation is to:
a. reduce and reshape occlusal length of the tooth by 3mm.
b. extract the opposing tooth and replace it with a fixed partial denture.
c. restore the maxillary molar to a satisfactory plane of occlusion with a cast restoration.
d. cut the maxillary extruded molar off the working cast, construct a mandibular fixed prosthesis and equilibrate the maxillary molar to the new occlusal plane after the prosthesis is cemented.
e. intrude the tooth to the correct plane of occlusion.
ANSWER: ( c )
a. The thickness of enamel is between 2.5mm at the cusp tips to 2.0mm at the incisal edges. (Fundamentals of Operative Dentistry Schwartz, Summit, Robbins 1996, page2). If we cut the tooth by 3mm, we will have stripped off the enamel and cut down into dentin exposing the tooth to greater sensitivity and making it more susceptible to wear and caries destruction.
b. Some dental common sense: If we extract this tooth, we are left with an edentulous space. Replacing it with a bridge requires us to cut down two unaffected teeth on either side. We then have a bridge which is more of a challenge to maintain. If we reduce and crown only the supererupeted tooth, then we need only treat one tooth, as opposed to three. We also have a single unit crown which is easier to maintain.
c. Sometimes a patient’s occlusion is disrupted by supraerupted teeth…. Often considerable reduction is needed to compensate for the supraeruption…..Sometimes even endodontic treatment is necessary to make enough room. When these teeth are prepared for restoration, the eventual occlusal plane must be carefully analyzed and the teeth reduced accordingly. Under these circumstances an apparent violation of the principles of conservation of tooth structure is preferable to the potential harm from a traumatic occlusal scheme. (Contemporary Fixed Prosthodontics Second Edition,
Rosenstiel, Land, Fujimoto 1995, p.150)
d. By simply adjusting the supraerupted tooth to the new occlusal plane we end up with the same problem that we have in (a). In this procedure we would be creating occlusal discrepancies that then must be corrected. We avoid this by proceeding in the fashion noted in (c).
e. Still looking for data on this one.
50. In what situation might a crown-root ratio of greater than 1:1 be considered adequate for a tooth used as a bridge abutment?
a. when the opposing tooth cusps interdigitate in the central fossa.
b. when the opposing teeth are artificial or periodontally compromised.
c. when the opposing roots are broader buccolingually than mesiodistally.
d. when the opposing roots are broader mesiodistally than buccolingually.
e. when the opposing teeth have a similar crown-root ratio.
ANSWER: ( b )
Crown-Root Ratio: This ratio is a measure of the length of the tooth occlusal to the alveolar crest of bone compared with the length of root embedded in the bone.
Optimum is 2:3… Minimum 1:1
a. Minimum of 1:1 under normal circumstances. (a) is normal circumstances.
b. There are situations in which a crown-root ratio grater than 1:1 might be considered adequate. If the occlusion opposing a proposed fixed partial denture is composed of artificial teeth, occlusal force will be diminished, with less stress on the abutment teeth. The occlusal force against a prosthetic device has been shown…26.0 lb for removable partial dentures and 54.5 lb for fixed partial dentures versus 150.0 lb for natural teeth. For the same reasons, an abutment tooth with a less than desirable crown-root ratio is more likely to successfully support a fixed partial denture if the opposing occlusion is composed of mobile, periodontally involved teeth, than if the opposing teeth are periodontally sound.
c. Abutment teeth that are broader labiolingually than they are mesiodistally are preferable to roots that are round in cross section…..as abutment teeth, not opposing teeth.
d. see ( c)
e. The opposing teeth may have a similar crown-root ratio but they are still natural teeth and able to exert 150.0 lb of pressure on teeth that are compromised because of their abutment status in support of a bridge.
All information for #50 above from: Fundamental of Fixed Prosthodontics, Third Edition,
Shillingburg, Hobo, Whitsett, 1997, p. 89-93
51. In RPD’s, the anatomy of the occlusal`` rest should include all of the following EXCEPT:
a. rounded triangular shape
b. apex nearest the center of the tooth
c. ½ the buccal lingual width of the tooth
d. angle formed with minor connector is less than 90 degrees
e. 1.5 mm of the marginal ridge is usually reduced
ANSWER: C (The buccal lingual width should be 1/3 not ½.)
Reference: Krol Removable Partial Denture Design(Outline Syllabus)1981 page 27, 28.
52. The positioning of a cast to be surveyed for designing a removable partial denture framework is determined by all of the following EXCEPT:
a. parallel guide planes
b. retention areas
c. interferences from soft and hard tissue undercuts
e. tripod marks
ANSWER: E Tripod marks are used to reposition the cast, not for the initial survey.
Reference: Krol Removable Partial Denture Design(Outline Syllabus)1981 page 15.
53. When trying in a removable partial denture framework, what should be reduced when pressure shows through the disclosing wax?
b. indirect retainer
c. guiding plane
d. retentive tip
e. none of the above
Disclosing Wax: Melted disclosing wax is placed on all framework surfaces that will contact teeth. This will help to determine why a framework will not seat properly.
The framework should be carefully removed from the mouth to avoid damaging the surface of the disclosing wax and then examined under magnification. The thickness of wax beneath occlusal rests and indirect retainers reliably indicates the degree to which the framework fails to seat. The inner surface of the framework under the disclosing wax should be examined for “high spots” or areas of metal showthrough that prevent the seating of the casting. The most common points of showthrough that interfere with seating occur above the survey line on the teeth. These areas generally occur under rests, at the shoulder of circumferential clasps, under embrasure clasps and interproximal extension of lingual plating.
The located areas of interference should be relieved by grinding the metal showthrough, which is most efficiently accomplished with a No. 2 round carbide bur in a high-speed handpiece.
The framework fits properly when the disclosing wax is displaced evenly, leaving a thin film of wax under the rests and indirect retainers.
Showthrough on areas below the survey line will not prevent the framework from seating. This will appear as a wipe-away of the disclosing wax, but it should not be relieved because it is beneficial. These areas are the guiding planes that guide the framework to place and prevent the tooth from being rocked each time the partial denture is inserted and withdrawn.
Clinical removable partial prosthodontics: Stewart, Rudd, Kuebker, C. V. Mosby Co. 1983, pp373-377.
54. A partially edentulous arch with teeth # 5,6,7,8,9,10 and 11 missing should be classified as a Kennedy:
a. Class I
b. Class II
c. Class III
d. Class IV
e. Class II, modification I
correct answer : ClassIV
Class I : Bilateral edentulous areas located posterior to the remaining natural teeth.
Class II : A unilateral edentulous area located posterior to the remaining natural teeth.
Class III : A unilateral edentulous area with natural teeth remaining both anterior and posterior to it.
Class IV : A single, but bilateral (crossing the midline), edentulous area located anterior to the remaining
55. Which of the following are the most common characteristics of denture stomatitis?
1. It is commonly a manifestation of oral candidiasis
2. It can occur in acrylic and metal prosthesis
3. The patient is often asymtomatic
4. There is a high rate of recurrence of if the prosthesis is not properly treated.
e. All of the above
correct answer: e all of the above
One of the clinical forms of oral candidiasis is denture stomatitis , also called chronic atrophic candidiasis.
Candidiasis is caused by an infection with a yeast-like fungus, Candida albicans , a relative common inhabitant of the oral cavity, GI tract, and vagina. This disease can occur in acrylic and metal prosthesis, can be asymtomatic and there is a high recurrence if the prosthesis is not also treated. Treatment of the disease should include both treatment of the tissue and the denture.
Fotos, Peter, and Hellstein, John W. , Candida and Candidosis, Epidemiology, Diagnosis and Therapeutic Management. Dental Clinics of North America, Vol. 36, No. 4, October 1992.
56. The most reliable landmark for determining the posterior height of the occlusal plane is a point:
a. Four millimeters below the parotid duct
b. Two millimeters above the resting height of the tongue
c. midway between the tuberosity of the maxilla and the retromolar pad.
D. At the middle of the retromolar pad
e. Three millimeters above the crest of the ridge
correct answer: d . at the middle of the retromolar pad
Rahn, Arthur O., Heartwell, Charles M. Textbook of Complete Dentures, 5th edition, pp. 352.
Complete Dentures, Naval Dental School., the “Toth” book.
Answers (a), (b), (c), (e) are simply not the anatomic landmark classically described as the determinant of the posterior height of the occlusal plane. Answer (a) four millimeters below the parotid duct, more correctly describes the anatomic guidelines used to establish the vertical position of the occlusal surface of the maxillary first molar. This is measured approximately 1/4 inch below the orifice of the duct from the parotid gland (Stensen’s Duct). This measurement is based on averages, which are not always reliable. Answer (b) two millimeters above the resting height of the tongue is a variable position and not a landmark. The actions of the tongue and cheek, along with the esthetics, primarily determine the lateral limits of the posterior teeth. Answer (c) midway between the tuberosity of the maxilla and the retromolar pad is incorrect because this would place the occlusal plane too high. The stress bearing mucosa in the mandibular arch is usually anterior to the stress bearing mucosa of the maxillary arch. If the mandibular residual ridge has a steep ascent toward the anterior border of the ramus of the mandible, the distal of the most distal mandibular tooth is placed anteriorly to the ascent. When a tooth is placed over the ascending ridge, the forces are directed to an inclined plane. Answer (d) three millimeters above the crest of the ridge is not correct because the ridge is not a constant height, being influenced by resorptive processes. The crests of the residual ridges are aids in positioning the artificial teeth if the natural teeth were recently extracted and the cortical plates of bone remain intact. The crests of the ridges do not remain in the same anteroposterior or mediolateral positions. Both arches are resorbed in a vertical and lingual direction. As the resorption of the alveolar ridge progresses, the maxillary arch becomes narrower and the mandibular arch becomes broader.
The occlusal surface of the last mandibular natural molar is on a plane approximately at the bottom of the upper third of the retromolar pad. This vertical position is usually compatible with activities of the tongue and the cheeks.
The retromolar pad is a pear shaped area containing glandular tissue, loose alveolar connective tissue, the lower margin of the pterygomandibular raphe, fibers of the buccinator and superior constrictor muscles, along with fibers from the temporal tendon. The retromolar pad will appear as a pear shaped depression at the distal ends of the alveolar grooves.
57. A patient returns to the dental office for his first post-insertion examination of recently placed
complete dentures. The patient complains of generalized soreness of the denture-supporting tissues.
The most likely cause of soreness would be
a. Incorrect height of occlusal plane
b. Unbalanced occlusion
c. Excessive peripheral seal
d. Overextension of the borders
e. Excessive vertical dimension
Ref: Complete Dentures, NDS 252, CAPT Toth, pg. 69 - Troubleshooting, Item C
“Ridges: generalized soreness , Cause: excessive VDO.
“Treatment: patient remount to lower VDO, or make new CDs.”
Therefore, the answer is e.
58. All of the following are factors that will determine the path of placement and removal of a removable
partial denture EXCEPT
a. Type of major connector used
b. Position of guiding planes
d. Retentive areas
Ref: Essentials of Removable Partial Denture Prosthesis, 3rd ed., Applegate pg. 103
Factors Influencing Choice of Path
“1. Interference to insertion and removal might result from the appliance being built into areas of tooth or mucosa undercut. By comparing different paths, one may be chosen by which the appliance can pass these points of prominence with least resistance.
2. Retention of the appliance against reasonable dislodging forces is desirable. The chosen path, in which the least interference is encountered, should also allow for adequate and equalized clasp retention.
3. Esthetics becomes a factor in choosing the path of insertion where anterior clasps need to be positioned in the least conspicuous areas, and where anterior tooth substitutes must be given pleasing form and alignment. In cases where an anterior tooth is to be replaced, the path of appliance insertion definitely becomes more limited in its deviation to right or left from vertical.
4. Guiding Planes on tooth surfaces should have a sufficient area of parallel relationship to each other so that they may serve to determine positively the direction of appliance movement. Only by forcing the appliance to remove in a definite direction, different from the escape path of the retentive clasp terminal, can retention be made to become a positive force.”
The only factor NOT mentioned by Applegate in his text is ‘Type of Major Connector Used’, therefore
the answer is a.
59. After processing full upper and lower dentures with cusped teeth, selective grinding to correct processing
errors should be performed. What is the correct sequence of grinding procedures?
a. Protrusive, centric, balancing, working
b. Centric, protrusive, balancing, working
c. Centric, working, balancing, protrusive
d. Centric, balancing, working, protrusive
e. Centric, working, protrusive, balancing
Ref: Textbook of Complete Dentures,5th ed. 1993, Rahn, Heartwell, pg. 397
Selective Grinding of Anatomic Teeth
7. “Use the following grinding procedures to ensure balanced occlusion
in the centric and eccentric position.
(B.) If the cusp is high in the centric and not in the eccentric position, deepen the fossae or the marginal ridges.”
8. “-Balanced gliding occlusion-use the following selective grinding procedures:
On the working side, reduce the inner inclines of (a) buccal cusps of the maxillary teeth and
(b) the lingual cusps of the mandibular teeth (Butt Rule).
On the balancing side, reduce the inner inclines of the mandibular cusps.
To achieve balance in protrusive excursion, reduce the distal inclines of the maxillary cusps and the mesial inclines of the mandibular cusps.”
Using the preceding described sequence leads us to answer c.
60. What is the correct sequence in the preparation of abutment teeth for removable partial dentures?
a. occlusal rest, proximal guide planes, buccal and lingual contours, polish
b. buccal and lingual contours, proximal guide planes, occlusal rest, polish
c. proximal guide planes, occlusal rests, buccal and lingual contours, polish
d. proximal guide planes, buccal and lingual contours, occlusal rest, polish
e. proximal guide planes, buccal and lingual contours, polish, occlusal rest
Abutment contours should be altered during mouth preparations in the following sequence: (1) proximal surface is prepared parallel to path of placement to create guiding plane, (2) height of contour on buccal and lingual surfaces is lowered when necessary to permit retentive clasp terminus to be located within gingival third of crown, bracing part of retentive arm at the junction of the mandible, and the gingival third of the crown, and reciprocal clasp arm on opposite side of tooth to be placed no higher than cervical portion of middle third of crown, (3) occlusal rest preparation that will direct occlusal forces along long axis of tooth.
Ref. McCracken’s Removable Partial Prosthodontics Ninth Edition: pp287-288.
61. Which would NOT alter cusp height?
a. greater vertical overlap of anterior teeth
b. increase in incisal guidance
c. increase in condylar angle
d. intercondylar distance increase
e. occlusal plane orientation change
Vertical determinants of occlusal morphology
Taller post cusps
Taller post cusps
Shorter post cusps
Plane of occlusion
More parallel the plane to condylar guidance
shorter post cusps
Curve of Spee
More acute the curve
Shorter most post cusps
Mandibular Lateral Translation
Greater the movement
More superior movement of rotating condyle
Greater the immediate sideshift
Shorter post cusps
Shorter post cusps
Shorter post cusps
Horizontal determinants of occlusal morphology
Distance from rotating condyle
Wider angle between pathways
Distance from midsagittal plane
Wider angle between pathways
Mandibular Lateral Translation
Wider angle between pathways
Ref. Mohl ND, Zarb GA, Carlsson GE, Rugh JD: A Textbook of Occlusion, Quintessence Publishing Co, Inc, 1998.
62. Which of the following materials should be avoided in the construction of a denture
for a patient who has received radiation therapy for oral cancer?
a. rubber base
c. polyvinyl siloxane
e. impression plaster
When dentures are fabricated for irradiated patients, light-body rubber base or reversible hydrocolloid (alginate) diluted to 1½ times its normal impression consistency are usually better tolerated than materials having greater viscosity. ZOE compounds may cause a burning sensation and should be avoided.
Conventional acrylic denture bases are best tolerated by irradiated tissues. Silicone soft liners have proven unsatisfactory because of their rough texture and tendency to support fungal growth.
Denture flanges must not be overextended if mucosal perforation and bone exposure are to be avoided.
Ref. Compend Contin Educ Dent Vol XV, No. 4: pg 450
63. Which of the following muscles aid in the retention and stabilization of complete dentures?
4. Medial pterygoids
5. Orbicularis oris
a. 1, 2, 4
b. 2, 3, 4
c. 1, 3, 5
d. 2, 5
e. 2, 3, 5
Masseters...powerful elevator muscle, if in function or hyperfunction, they can displace the denture if not border molded properly. Should allow for the masseteric notch on the distal buccal flange of the denture base.
Buccinators...aid in food bolus movement and the facial seal of the denture flange is due to the drape of the cheek and not the muscle.
Mylohyoids...borders should be extended in this area as much as the patient can tolerate to aid in retention, a major mistake is to not extend this area for fear of gagging patient.
Medial pterygoids...powerful elevator muscle but should be too distal to influence the flange unless over extended.
Orbicularis oris...major muscle of the labial vestibule, careful border molding is required to allow for hyper-activity, a thick border lends for a better seal than thin.
BEST AS I CAN TELL FROM MY READINGS OF “IMPRESSIONS FOR COMPLETE DENTURES” BY Bernard Levin....the correct answer is “d”.
64. Which of the following is the MOST important factor when making a record of centric relation for complete dentures?
a. The patient should be in a reclined position
b. Accurate and stable recording bases should be used
c. Central bearing plates and a tracing device should be used
d. The patient should be allowed to close in his accustomed position when a wax registration is used.
e. The patient should not wear their dentures for 24 hours prior to recording centric relation.
A. Rahn in his book “Textbook of Complete Dentures” states that you should have the patient in an upright position...Boucher concurs....
B. Cannot take CR without these.
C. A particular technique but not the standard. (Textbook of Complete Dentures)
D. This is CO as by definition (Textbook of Complete Dentures)
E. This has no impact on the taking of occlusion records. (Boucher or Rahn or Levin)
therefore: B is then correct answer
A properly-shaped occlusal or incisal rest for a removable partial denture will provide …
increased retention <rests can also serve as an indirect retainer when in combination with a clasp > p. 57 Krol 4th edition
flexibility to absorb stress < location & design of rests, clasps arms, and the position of minor connectors as they relate to guiding planes control the stress to abutments.> p. 113 McCracken's RPD 8th ed.
resistance to vertical displacement
definitive guidance for the path of insertion < achieved by first surveying. Guide planes control the path of placement and removal.>p. 85 McCracken's RPD 8th ed.
prevent rotation of clasp assembly
"A rest is a rigid extension of a partial denture which contacts a remaining tooth in a prepared rest seat to transmit vertical and horizontal forces. Requirements : (1) should have sufficient thickness of metal to prevent fracture (1.5- 2mm). (2) should be placed only on surfaces that will direct forces along long axes of teeth. Should not be placed on inclined surfaces to ensure axially directed forces. (3) should be extended as close to the center of the tooth (M-D) as feasible to direct axial forces. (4) should be placed in rest seats which demonstrate smooth and rounded internal line angles." p. 59 Krol 4th edition
66. A lingual bar major connector should be…
located 4mm inferior to the gingival margin
at least 4mm in width
considered if more than 8mm exist between the gingival margin and the floor of the mouth <inferior border may be placed at the functional depth of the vestibule
beaded on the inferior border for good tissue contact <the inferior border of the lingual bar is gently rounded to avoid irritation> <AP straps, palatal connectors>p. 172, 514 McCracken's RPD 8th ed.
Lingual bar: p. 59 Krol 4th edition
Indications-- lingual vestibule must be > 7mm; gingival margin should be > 3mm away from superior border of lingual bar
Dimensions-- half pear-shaped in x-section with dimensions 2 mm x 4 mm (anterior-posterior x to superior-inferior)
Answer is a. 1, 2, 3
When constructing complete dentures, which of the following factors is determined solely by the patient’s anatomical characteristics?
the compensating curve
orientation of the occlusal plane
Correct answer is D
Incisal Guidance- Anterior guidance is incisal guidance in complete dentures, as set on the articulator. Vitally important to harmony in denture balance, anterior guidance is selected by the dentist. The horizontal and vertical overlap of the anterior teeth are primarily based upon the esthetic, phonetic, and functional requirements.
Is an end controlling factor is under the control of dentist. Balanced occlusion is virtually impossible when incisal guidance is greater than condylar guidance. This has great impact on esthetics in term of incisal overlap and overjet. Ideally, incisal guidance in complete dentures will allow bilateral posterior contact in all ranges of function.
Centric Relation- The maxillomandibular relation in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior superior position against the slopes of the articular eminences, regardless of any tooth to tooth relationship.
Compensating curve- is created relative to the occlusal plane during the posterior set up and compensates for Christensen’s phenomenon in excursions. ( Christensen’s phenomenon- the creation of space between the posterior teeth bilaterally during protrusion or the balancing side during lateral excursions. Protrusive and laterotrusive interocclusal records register the gap produced by Christensen’s phenomenon. The gap is caused by the incline of the temporal eminence.)
Occlusal plane- is determined by the anterior incisal edges and the retromolar pads and is oriented parallel to the ridges.
Condylar guidance- the pathways of the condyles in the temporomandibular joints. Though primarily related to the shape of the articulating surfaces, condylar guidance is also influence by ligaments and muscles. Condylar guidance is the posterior determinant of mandibular movement, and allows a range of motion limited only by bones, ligaments, and muscles. A rectilinear representation to an articulator using protrusive and lateral interocclusal records. A curvilinear representation of condylar guidance may be recorded by pantographic or stereographic tracing and transferred to a fully adjustable articulator.
Condylar guidance is end controlling factor is measured on patient.
Thielman’s quint = Hanau’s quint
Centric relation is not in this quint but the other listed above are.
CH CC OP
Five factors of balanced occlusion . Also known as Hanau’s quint.
Condylar guidance (CG)
Incisal guidance (IG)
Cusp height (CH)
Compensating Curve (CC)
Occlusal Plane (OP)
If a factor in the numerator is increased (only the IG can be), then one or all of the factors in the denominator must be increased to maintain the balanced occlusion. Further an increase in any one of the denominators requires a decrease in one of the other in the denominators when numerator is constant.
It is important to remember the end controlling factors and their relationship. (IG, CG)
Also important: No matter what posterior tooth form is used balanced occlusion ensures the posterior teeth on both sides of the arch contact harmoniously in any jaw position.
REF: Occlusion Class notes 1996
Toth. Complete Denture 1996. AKA the world according to Toth.
The primary function of the reciprocal clasp (bracing) arm is to
stabilize abutment teeth
act as a direct retainer
act as indirect retainer
guide the partial in its path of insertion
counteract any force transmitted by retentive arm
Correct answer is E.
Reciprocation (reciprocation action)- Resistance to horizontal forces exerted on a tooth by an active retentive element.
1. Provided by rigid bracing components contacting the surface of the tooth opposite the retentive clasp arm
Opposes forces exerted by the retentive clasp arm terminal through its action distance during seating and unseating of partial. This type of reciprocation is relatively unimportant since the force exerted by the retentive terminal during seating and unseating is transient, limited in magnitude and occurs infrequently.
Prevents tooth movement that may result from over adjustment of retentive clasp arms. This type of reciprocation is important.
Only one flexible retentive terminal should be used on each clasp, permitting the rigid component or components on the opposite side of the tooth to provide reciprocation and prevent tooth movement
Rigid components do not engage undercuts unless rotational path of placement is used.
Reciprocating arms are above, but close to height of contour. Reciprocating arms contacts tooth at the same time or before the retentive arm. A retentive clasp must be opposed by reciprocating elements or an element of the framework that encircles at least 180 degrees of the tooth.
They do stabilize the tooth but that is not their primary function.
Direct retainer- A clasp or attachment applied to an abutment tooth for the purpose of retaining a removable partial denture. It is directly responsible for retention of the prosthesis. I.e. clasps
Categories of clasps- cast circumferential (suprabulge), cast bar (infrabulge), combination ( 1. Cast circumferential clasp arm and cast bar clasp arm. 2. Cast clasp arm and wrought wire clasp arm)
Indirect retainer- A component of a removable partial denture, located on the opposite side of the fulcrum line, that assists the direct retainer in preventing displacement of an extension base through mechanical leverage. I.e. rests, minor connectors and proximal plates, lingual plates .
Resists movements of RPD away from tissue base.
Indirect retainer- are rests anterior to fulcrum line.
The effectiveness of indirect retainers is thought to be directly proportional to their distance from the fulcrum line. They are placed as far anterior to the fulcrum line as possible.
Ideally placed perpendicular to fulcrum line.
Fulcrum line-an imaginary line through the most distal abutment (rest) on either side of the arch. Multiple fulcrum lines can exist.
Guide planes- Vertical parallel surfaces of abutment teeth oriented so as to contribute to direction to the path of placement and dislodgment of removable partial denture
REF: RPD class notes 1997
Krol , J. Removable Partial Denture Design, 4th ed. Indent Publisher. 1990 pg. 1,3,47-49.
69. The dual path of insertion concept of removable partial denture design is routinely characterized by
utilization of tooth undercuts adjacent to edentulous areas for retention
utilization of either anterior or posterior edentulous areas
retention gained through minor connectors or proximal plates
utilization of infrabulge flexible retentive components (This statement is false because they are rigid retainers and uses suprabulge clasps)
all of the above
Correct answer is B.
The rotational path design concept uses rigid portion of the framework as the retentive component.
Either a minor connector or proximal plate provides retention through its intimate contact with proximal tooth surface below the height of contour or survey line as indicated at zero degree tilt. These rigid retentive components must gain access to the infrabulge portion of the tooth by rotating into place. A specifically designed rest in conjunction with this retentive component satisfies the basic requirements of clasp design. The effectiveness of the rotational path design is dependent on the one or two conventional clasp assemblies placed on the partial.
Rotational path partials utilize tooth undercuts adjacent to edentulous areas for retention.
Rotational path partials are utilized in anterior or posterior edentulous areas.
With a conventional path of insertion all the rests are seated more or less simultaneously. With a rotational path partial one segment of the removable partial denture is seated first; then the remainder of the prosthesis is rotated into position. The main advantage of rotational path design when compared to conventional RPD is the minimal use of clasps. This enhances esthetics and reduces the tendency toward plaque accumulation.
Types of rotational paths
Anteroposterior (AP)- Anterior segment seated first.
Posteroanterior (PA)- Posterior segment seated first.
Lateral. The edentulous side is seated first, followed by seating the opposite side.
Categories of rotational path designs.
Rotational centers are located at the termini of the extended rests of rigid retainers.
The rotational centers on each side of the arch determine the axis of rotation for placement of partial dentures.
The rotational centers are seated first then the prosthesis is rotated into place.
Includes AP and PA paths of rotation replacing missing posterior teeth, and lateral paths of rotation utilizing proximolingual undercuts.
CATEGORY II ( Sometimes referred to as dual path of placement)
Rotational centers are located at the gingival extensions of the rigid retainers.
The rotational centers on each side of the arch determine the axis of rotation for final placement of the partial denture.
To gain access to rotational centers, the segment with rigid retainers is seated first along the straight path. The prosthesis is rotated into place.
Includes all AP paths of rotation replacing missing anterior teeth and al lateral paths of rotation utilizing proximofacial undercuts.
Advantages of Rotational Paths
Minimizes number of clasps, reducing tooth coverage
May reduce plaque accumulation.
Anterior clasps may often be eliminated, improving esthetics.
May be used in preference to an anterior fixed prosthesis to attain better esthetics.
Minimal tooth preparation when compared to a precision attachment or fixed prosthesis.
May often be used in absence of lingual or facial undercuts.
Distortion of rigid retentive components is unlikely.
May prevent further tipping of abutment teeth contacted by rigid retainer.
Disadvantage of the Rotational Paths
Adjustment of the rigid retentive component is difficult.
Less tolerance for error.
Requires well prepared rest seats.
REF: Jacobsen, T. E. , Krol, A. J. Rotational Path Removable Partial Design. Journal of Prosthetic Dentistry. Vol. 48 No.4 October 1982. p 370-376.
REF: Krol, A. J., Jacobsen, T.E., Removable Partial Denture Design, 4th ed. Indent Publisher. 1990 pg. 69-88.
70. What part of the denture bearing area provides best continuous vertical support to the mandibular denture?
buccal shelf area
crest of ridge
all impression ridge
crest of anterior ridge
Mcgivney, G. P., Castleberry, D.J., McCracken’s Removable Partial Prosthodontics, Ninth edition. Mosby, 1995, 324-325 .
The crest of the bony mandibular residual ridge is most often cancellous in nature. Pressures placed on tissues overlying the crest of the mandibular residual ridge usually result in irritation of these tissues, accompanied by the sequelae of chronic inflammation. The buccal shelf region (bounded by the external oblique line and crest of the alveolar ridge) seems to be better suited for a primary stress-bearing role because it is covered by relatively firm, dense, fibrous connective tissue supported by cortical bone.
71. What are the advantages of the RPI clasp design in removable partial dentures as advocated by Krol?
the I-bar is more esthetic in most instances since it contacts the tooth minimally
the I-bar, proximal plate and mesial minor connector provide adequate encirclement of the tooth by engaging more than 200 degrees
the RPI clasp contacts the tooth minimally and is best used on caries-prone patients
a mesial rest eliminates the potential "pump-handle" effect that a force on the base would provide with a distal rest
all of the above
Krol, AJ, RPI (rest, proximal plate, I bar) clasp retainer and its modifications, Dent Clin North Am 1973;17(4):631-649.
Requirements of a Properly designed clasp retainer.
Support: the resistance to the vertical components of masticatory force which prevent the partial from being displaced toward the soft tissue. It is provided by the occlusal rest.
Bracing (stabilization): the resistance to horizontal components of force. It is provided by the ridge components of the clasp including the occlusal rest and the minor connector.
Retention: the resistance to dislodgment in an occlusal direction. It is provided by the clasp tip engaging the undercut when a dislodging force is applied.
Adequate Encirclement: the clasp assembly must engage more than 180 (more than half the circumference ) to prevent the tooth from moving out of the clasp.
Reciprocation (reciprocal action): each force exerted on a tooth by a clasp arm must be offset by and equal and opposite (compensation) force. This is provided by the reciprocal arm located on the opposite side of the tooth. Normally, the reciprocal arm does not engage and undercut.
Passivity: when the clasp is in place on the tooth, it should be at rest. Its retentive function is activated only when a dislodging force is applied. A force in an occlusal direction causes the retentive arm to engage the undercut from a gingival direction and so retain the partial denture in place. The clasp should never “grip” the tooth.
...both the I bar and the proximal plate disengage the abutment and thereby reduce torquing of the tooth. The mesial rest eliminates the potential “pump handle” effect that a force on the base often endues with a distal rest.
The RPI clasp contacts the tooth minimally and is advantageously used on caries prone patients, and since the I bar itself makes very little contact with the tooth, it is usually more esthetic than most other clasp arms.
72. Which of the following statements are true concerning the altered cast technique?
the initial impression is used to fabricate RPD framework to remaining teeth
allows for the development of a functional type impression
allows selective tissue impression for more ideal distribution of the load on the distal extension ridge area
the second impression is used to capture the relationship of the framework to the soft tissue
all of the above
Mcgivney, G. P., Castleberry, D.J., McCracken’s Removable Partial Prosthodontics, Ninth edition. Mosby, 1995, 336-343 .
Fluid wax function impression method. (Applegate method): ...may be used to make a reline impression or to correct the original master cast. ...there is less danger of over displacement of tissues by the application of vertical forces. ...recording primary stress-bearing areas in their functional form, recording other basal seat or nonbearing areas in their anatomic form, and maximum extension of borders within the physiologic tolerance of bordering structures.
Holmes, JB, the altered cast impression procedure for the distal extension removable partial denture. Dent Clin North Am 1970 Jul;14(3):569-582.
The altered cast procedure described here is a modification of Applegate’s fluid wax functional impression.
The purpose is to obtain a partial denture with comfortable, functional support that will preserve rather than abuse the oral structures.
An error in complete denture construction that frequently causes serious speech interference’s is:
Placing the maxillary anterior teeth too far facially or lingually. Which interferes with production of the “f” sound.
Making the maxillary anteriors too long, which causes the patients’ “f” s to sound like “v” s.
Placing the maxillary anteriors to low, which interferes with the production of the “m” sound
Excessive thickness in the posterior palatal region, which interferes with the production of the “t” sound.
Inadequate interocclusal space, thus causing “Th” and “T” sounds to be indistinct.
Errors in placing the maxillary teeth create problems in the "F" and "V" sounds.
Excessive thickness in the posterior palate causes difficulty in swallowing.
Errors in “T” and “DTH” sounds are caused by inadequate interocclusal space. Ref. The Toth book
Cross-tooth. Cross-arch balance is indicated in
restoring a natural dentition.
using non-anatomical teeth on a flat ridge.
Mandibular Kennedy class 3 RPD’s opposing natural dentition.
using anatomic teeth on a prominent ridge with a broad thick base.
mandibular class 1 RPD’s opposing natural dentition.
Cross tooth, cross arch balance does not normally exist in the natural dentition. Nonworking contacts are normally considered not good in the natural dentition.
With nonanatomic teeth you can not get cross arch balance. You need only to look at Hanau quint CG IG / CH OP CC = balanced occlusion to see that cusp height at 0 degrees will not work.
One of the major purposes of cross arch balance is to stabilize the dentures in eccentric movements. With a class 3 partial that stabilization is not needed since the RPD is tooth borne.
A thick prominent ridge is the indication for anatomic teeth along with repeatable centric, and healthy tissue.
A class 1 mandibular RPD bilateral eccentric contacts of the teeth are not needed to stabilize the denture. In the class 1 maxillary RPD balanced occlusion is desirable to compensate for the unfavorable position of the teeth in relation to the ridge. McCracken Pg. 346-347
Which of the following statements concerning lingualized occlusion for RPD’s is correct?
Results in the placement of the mandibular teeth lingual to the ridge crest.
Uses anatomical teeth for the max denture .
Cannot be used effectively when a complete denture opposes a RPD.
Used to compensate for prognathism and resorbed maxillary arches, resulting in the maxillary teeth being set lingual to the mandibular teeth.
Concentrates forces of occlusion on lingual cusps of the upper posterior teeth and vertical forces are centralized on the mandibular teeth.
contraindicated for patients with flat ridges that are unable to resist lateral forces.
In lingualized occlusion the teeth are over the ridge. It is neutrocentric occlusion where the teeth are lingual to the ridge.
Lingualized occlusion uses a cusped tooth for esthetics and food penetrating ability against a flat or a shallow cusped tooth.
There is no reason why lingualized occlusion could not be used with a CD/RPD combo
Lingualized gets its name from the fact that the lingual cusps of the maxillary are the major functioning occlusal element.
Although reduced the lateral forces are still present so if those forces can not be tolerated the it is contraindicated.
76. Serial extraction is a method of orthodontic treatment. which of the following conditions meets an ideal serial extraction case?
1. is indicated more frequently in Class II than in Class I malocclusions.
2. is used only to solve problems of insufficient arch length.
3. is commonly restricted to the primary teeth.
4. a patient with Class I canine and molar relationship with
6mm tooth-mass/arch-size discrepancy per quadrant and a
normal skeletal growth pattern.
5. normal extraction sequence is d's, c's and 4's.
6. treatment results in increased VO, lower lingual holding arch required to prevent dumping of incisors.
Dentistry for the Child and Adolescent Forth Edition, McDonald, Avery 1983 p 609-614.
Serial Extraction: A procedure that involves the orderly removal of selected primary and permanent teeth in a predetermined sequence. Its use is indicated only in the dental arches that are structurally inadequate for the developing teeth and when there is little or no hope of ever attaining a normal size and proportion.
If the discrepancy is less than 7mm throughout the arch the dentition should be allowed to develop past the serial extraction stage and until all first premolars have erupted.
Serial extraction is indicated primarily in severe Class I malocclusion in the mixed dentition that has insufficient arch length for the amount of tooth material. Many dentists have unrealistically believed that serial extraction would solve all Class I occlusion problems. Too often they have been disillusioned to learn that serial extraction in itself rarely creates an acceptable occlusal relationship and that certain adverse reactions will result if the procedure is not followed by adequate orthodontic treatment.
It is generally agreed that a malocclusion for which serial extraction may be considered is characterized by: Severe crowding of the anterior teeth, Premature loss of one or more of the primary canines, Midline deviations, Impacted or displaced lateral incisors, and Gross deficiency in arch length.
The primary canine is removed first in the serial extraction procedure, then the first primary molar, and finally the first premolar. The interval between extractions varies: 6 to 15 months.
Dewel advocates an alternative extraction sequence; extract the first primary molar then 6 to 12 months later extract the primary canine. If growth exceeds expectations, as it usually does, there will be no need to extract the first premolar.
A passive lingual arch should be used to maintain the position of the mandibular first permanent molars and to prevent the incisors from tipping lingually. A Hawley is the maintainer of choice in the maxillary arch.
77. An 8 year old boy presents with a small Ellis Class III fracture of #9 that occurred 1 hour ago, the treatment of choice would be:
a. formocresol pulpotomy
b. pulp cap
d. pulpectomy technique
Dentistry for the Child and Adolescent Forth Edition, McDonald, Avery 1983 p 433.
Ellis Classification of crown fracture:
Class I - Simple fracture of the crown involving little or no dentin.
Class II - Extensive fracture of the crown involving considerable dentin but not the dental pulp
Class III Extensive fracture of the crown with an exposure of the dental pulp
Class IV Loss of the entire crown
Dentistry for the Child and Adolescent Forth Edition, McDonald, Avery 1983 p 440-446.
In the treatment of vital pulp exposure there are at least three choices of treatment- direct pulp therapy (pulp capping), pulpotomy, and pulpectomy with endodontic therapy.
Direct Pulp therapy (pulp capping)- if the patient is seen within an hour or two after the injury, if the vital exposure is small, and if sufficient crown remains to retain a temporary restoration to support the capping material and prevent the ingress of oral fluids, the treatment of choice is direct pulp therapy. If the final restoration of the tooth will require the utilization of the pulp chamber or the pulp canal for a post, a pulpotomy or a pulpectomy is the treatment of choice.
Even though the pulp at the exposure site has been exposed to oral fluids for a period of time, the tooth should be isolated with a rubber dam, and the treatment completed in a surgically clean environment. It has long been assumed that the health pulp will survive and will repair small injuries, even in the presence of a few bacteria, the same as any other connective tissue.
A dressing of calcium hydroxide is currently the material of choice as a pulp capping agent. The prime requisite of pulpal healing is an adequate seal against oral fluids. Therefore a restoration should be placed immediately that will protect the pulp-capping material.
Puplotomy- if the pulp exposure in the traumatized immature permanent (open apex) tooth is large, if the patient did not seek treatment until several hours or days after the injury, or if there is insufficient crown remaining to hold a temporary restoration, the immediate treatment of choice is calcium hydroxide pulpotomy. The successful pulpotomy allows the pulp in the root to
maintain its vitality an allow the apical portion to continue to develop (apexigenesis).
Pulpectomy- The trauma may have caused a very small pulp exposure that was overlooked, or the pulp may have been devitalized as a result of injury or actual severing of the apical vessels. Apexification is the procedure to create a calcific bridge to close the open apex of a nonvital tooth.
78. Which of the following statements is true about X-rays?
1. Kinetic energy varies directly with kvp
2. Filtration is intended to block low level energy waves
3. X-ray beam intensity varies inversely with ma
4. Collimation restricts the cross section of the beam
e. all of the above
X-Rays in Dentistry, Eastman Kodak Company1977, p 2-12.
Increasing the Kilovoltage increases the overall intensity pattern of transmitted x-rays. New more penetrating x-rays are produced.
Filtration absorbs the longer wavelength (lower energy), less penetrating rays, which would otherwise be absorbed by the patient’s skin.
X-ray intensities will increase as the quantity of X-ray radiation increases. Increasing ma will increase the quantity of x-rays.
The aperture diaphragm (collimation) in the cone restricts the beam to that part of the patient to be examined thereby reducing scattered radiation.
79. How should a restorable primary second molar with a necrotic pulp be treated in a five year old?
a. allow it to remain unless it becomes painful.
b. allow it to remain but treat with a fromocresol pulpotomy
c. treat tooth endodontically
d. drain tooth through an opening in the crown but retain as a space maintainer
e. extract to prevent damage to surrounding tissue and developing succedaneous tooth.
a. answer is incorrect because the tooth is still a source of infection and simply leaving it until it hurts is not good dentistry. It is unwise to maintain untreated primary infected teeth in the mouth.
b. a formocresol pulpotomy is indicated for vital teeth with no evidence of irreversible inflammation in the apical pulp.
c. correct choice the tooth should be treated endodontically Endodontic procedures for the treatment of primary teeth with necrotic pulps are indicated if the canals are accessible and if there is evidence of essentially normal supporting bone. The morphology of the root canals in primary teeth ( thinness of root walls and pulpal floor, curved roots) makes endodontic treatment difficult and often impractical. If the root canal cannot be properly cleansed of necrotic material, sterilized and adequately filled, endodontic therapy is not indicated. The correct endodontic therapy involves the use of gutta percha when there is no succeeding tooth and ZOE, pure, not IRM or other reinforced cement, when there is a succadaneous tooth. It is essential that 100% of the root be present and there is apical closure.
d. Although these teeth can be opened for drainage and often remain asymtomatic for an indefinite period of time, they are a source of infection and should be treated or removed.
e. Extraction of the tooth presents a space maintenance problem, being that the first permanent molar is probably not fully erupted into position. Early loss of the tooth would necessitate the use of a distal shoe ( not very kind to gingival tissue) or possibly the use of a band and loop ads eruption of the first permanent molar allows. Retention of the natural dentition is preferred.
Dentistry for the Child and Adolescent. McDonald, Ralph, E. ,Avery, David R., Sixth Edition, pp. 442-444. Class note from Dr. Bookwalter
80. Bone or tooth fractures are best visualized when the x-ray beam is directed ____________ to the line of fracture.
c. Parallel is the correct answer
If the central ray of the x-ray beam lies in the plane of the fracture, the fracture may be visible as a radiolucent line on the radiograph. Usually, however, radiographs are not useful in identifying vertical root fractures in their early stages. When the orientation of the x-ray beam is parallel with the plane of a root fracture, the fracture appears as a sharp radiolucent line between the fragments. If, however, the orientation of the beam is not directly through the fracture but some of the tooth structure is superimposed over the fracture, the image of the fracture appears as a more poorly defined gray shadow. Most nondisplaced root fractures are usually difficult to demonstrate radiographically, and several views may be necessary.
Oral Radiology, Principles and Interpretion. Goaz and White. 3rd Edition. 1994.
81. Assuming the sealant to be intact, the most probable outcome of a sealant being placed over an existing carious lesion is tat the
a. microbiology of the caries process is altered and usually spreads more laterally
b. microbiology of the caries process is unaltered and continues, but at a slower rate.
c. carious lesion becomes bacteriologically more active but spreads at a much slower rate.
d. carious lesion becomes bacteriologically inactive and the process stops.
e. carious lesion remains active but process spreads laterally rather than pulpally.
d. correct answer The cariostatic properties of sealants are attributed to the physical obstruction of the pits and grooves. This prevents the penetration of fermentable carbohydrates, and so the remaining bacteria cannot produce acid in cariogenic concentration. The carious lesion becomes bacteriologically inactive and the process stops.
The bacteriologic process is altered but there is no evidence that the process spreads more laterally. (#1)
The bacteriologic process is definitely altered and thus choice # 2 is incorrect. The bacteriologic process is not more active following sealant application, but actually a 2000-fold decrease in the cultivable microorganisms has been reported. ( # c)
I could find no reference that addressed the lateral spread of carious lesions. (#E).
Going (1984) reported that after the results of many well-documented studies, the fear of sealing incipient pits and fissures is not warranted. Sufficient studies of scientific merit reported negative or low bacterial concentrations after several years of sealing teeth.
Dentistry for the Child and the Adolescent. 6th Edition. McDonald, Ralph E. , and Avery, David. 1994.
82. In teeth affected by active periodontal disease, orthodontic procedures
a. are slower to achieve movement than are in teeth not affected by periodontal disease.
b. are contraindicated where approximately half of the supporting bone has been lost.
c. should not be attempted in patient older than 40.
d. usually do not require post-movement retention.
e. must be delayed until marginal inflammation and active periodontal disease is under control.
Periodontal problems are rarely a major concern during orthodontic treatment of children and adolescents,
both because periodontal disease usually does not arise at an early age and because tissue resistance to the irritation produced by orthodontic appliances is higher in younger patients.
The odds are that any patient over the age of 35 has some periodontal problems that could affect orthodontic treatment. There is no contraindication to treating adult patients who have periodontal disease, as long as the disease has been brought under control.
Minimal Periodontal Involvement- Wherever the amount of attached gingiva is inadequate, there is a risk that the soft tissue attachment will strip away from the tooth. Orthodontic treatment accentuates this tendancy. A gingival graft might be indicated prior to orthodontic treatment.
Moderate Periodontal Involvement- Unless a patient can maintain periodontal health after initial therapy, orthodontic treatment is potentially damaging rather than beneficial. A period of observation should follow preliminary treatment before orthodontics.
Severe Periodontal Involvement- Periodontal maintenance should be scheduled at more frequent intervals.
Every 3-4 weeks orthodontic forces must be kept to a minimum because of the reduced area of periodontal ligament following bone loss.
Ref: Proffit, William R., Contemporary Orthodontics 1986, p508-511
In selecting a case for molar uprighting, caution must be exercised when
the molar is tipped more than 30 degrees
the patient is over 40 years old
the patient has an acceptable occlusal plane
there are spaces between the maxillary anterior teeth
the patient presents with a steep mandibular plane angle
Correct answer is e
A steep mandibular plane angle has a skeletal pattern that will make the patient naturally want to open. There may already be a minimal anterior guidance. If you upright the molar you can open the bite even more.
The degree of the tip is not a big concern. The more tipped the, the more of a challenge it will be to upright the molar, but it can be done.
Age is not a factor.
Spacing between maxillary anterior teeth will not effect the uprighting of the molar.
An acceptable occlusion is a indication for molar uprighting.
Class Notes Maskeroni 1996
Vanarsdall, R. Molar Uprighting. Ormco Corporation, 1997. Page 5.
What is the recommended daily fluoride supplement for a 2 year old child who resides in an area where public water supply contains less than .3ppm fluoride?
no supplement needed for this age
Correct answer is b
Fluoride supplementation as accepted by the ADA council on scientific Affairs.
Fluoride ion concentration in drinking water
AGE <0. 3 ppm 0. 3-0. 6 ppm >0. 6 ppm
Birth-6 months None None None
6 months- 3 years 0.25 mg/day None None
3-6 years 0.50 mg/day 0.25mg/day None
6-16 years 1.00 mg/day 0.50mg /day None
REF: Fluoride update. JADA, Vol 126, December 1995 page 1622
A dark radiographic film may be the result of
long development time
short development time
developer concentration high
temperature too high
Correct answer is d.
Developing - Film is developed in a certain amount of time at a certain temperature within a limited range of temperature. The action of developing agents on an exposed silver halide crystal is to continue the process of precipitating the silver in the entire crystal until all of the silver is deposited at the site of the crystal and the bromine is released into developing solution. The unexposed crystals, or those not containing the silver specks or latent image, are not affected by the developing solution .
More than one developing agent is present in the developer solution, and one of them hydroquinone is sensitive to changes in temperature. This results in overactivity of Elon at temperatures that are too low and corresponding relative overactivity of hydroquinone at temperatures that are too high. These two developing contrast differently; thus the temperature of the developing solution affects radiographic contrast. The higher the temperature, the shorter the time needed to develop the film.
HYDROQUINONE- brings out sharp contrast. Hydorquinone is inactive at low temperature (developing low contrast. Hydroquinone is very active at high temperatures (developing high contrast)
ELON brings out gray shades
ELON or METOL - Brings out images quickly but produces low contrast. Not effected by temperature. Less active then hydroquinone.
HYDROQUINONE- builds up contrast slowly during entire development period. (is sensitive to temperature)
SODIUM SULFITE-prevents oxidation of developer
(Alkali)SODIUM CARBONATE- Governs activity of developing agents; provides necessary alkaline medium and softens gelatin of allow developing agents to reach silver bromide crystals
POTASSIUM BROMIDE- controls activity of developing agents and prevents chemical fog
-decreases the rate of development of unexposed crystals (fog)
After it is developed, the film is rinsed in water for at least 30 seconds and then placed in fixing solution. Rinsing is done to remove the alkaline developer on the surface of the film an film rack and to prevent its being carried over to the acid fixer, where it would deteriorate the fixing solution. The developed film is left in the fixer for a total of 10 to 15 minutes but the radiograph can be used prior to total fixing. The fixer solution removes all of the unexposed or underdeveloped silver halide crystals and rehardens the emulsion, which softened during the developing process.
Failure to properly fix a films permits any residual silver halide crystals in the emulsion to give the film a fogged appearance. In addition, sufficient time is necessary to harden the emulsion.
SODIUM THIOSULFATE- Removes unexposed silver bromide crystals from solution by forming stable, water soluble complexes.
SODIUM SULFITE- prevents deterioration of hypo and precipitation of sulfur.
Prevents the oxidation of any developer which may have contaminated the fixer.
Complexed with the colored oxidized developer and removes it from the fixer before it can stain the film.
POTASSIUM ALUM- Shrinks and hardens gelatin.( Incorporates with gelatin to become more resistant to abrasion. Decreases the swelling of gelatin.)
ACETIC ACID- Provides necessary acid medium. Neutralizes developer, thereby, stops development thus reduces potential for fog. Prevents contamination of fixer.
After fixing, the film is washed in running water for 20-30 minutes. The time varies with the rate of water flow Washing removes the chemicals of the fixing solution from emulsion. Failure to wash a film properly will result in chemical stains producing a brown discoloration after a period of time.
DARK FILM (High Density)- Too long exposure, kVp too high for exposure time, too short o source to film distance, mA too high for exposure time, developing time too long, developer temperature too high, developer strength too high .
LIGHT FILM (low density)- Too short exposure, too great source to film distance, too low kVp. Too low mA reversed film packet. Development time too short. Low development temperature, exhausted or diluted developing solutions.
High contrast film (darks too dark and lights too light)- low penetration (kVp too low), over development, too long exposure.
Low contrast (all gray ones)- Excess penetration (kVp too high) under development, excess scatter fog , under exposure.
REF: Dental Radiology course 1-5 for common errors, ORAL MEDICINE DEPARTMENT BETHESDA. 1997
REF: Wuerhmann, A, DENTAL RADIOLOGY 4th edition, pages 30-33. 1977
An isolated cross-bite of a permanent maxillary incisor in the mixed dentition is most often associated with
prolonged retention of a primary tooth
an abnormal labial frenum
skeletal growth problems
Correct answer is a.
In the mixed dentition period, both permanent and primary teeth are present in the mouth. The early phase or stage 1 is the period when four permanent first molars erupt distal to the second primary molars and eight permanent incisors erupt after primary incisors are shed. This usually occurs in a variable sequence from 5 to 8 years of age. Most children experience these events around age 6-8 years of age. Age of eruption is not as important as the location of eruption. Normally the permanent first molars erupt end to end or Angle Class I.
Dental development is a function of tooth formation and not chronologic age or skeletal development. Teeth usually erupt with the root one-half to three quarters formed. If more than three quarters of the root is completed and the tooth is not erupted, methods to assist eruption are indicated. This usually involves surgery to remove such obstacles as over retained primary teeth or roots, fibrous gingiva.
Permanent incisors that erupt before the loss of primary successor may be deflected to the lingual. (or the presence of a supernumerary tooth or idiopathic lack of space in the dental space. When the maxillary incisors are involved, this can results in lingual crossbites. This condition should be treated as soon as observed . Prolonged retention of the primary tooth is the most common.
The second stage is the transition from mixed dentition to permanent dentition commonly occurs from ages 9-13. The primary cuspid and first and second molars are replaced by permanent cuspid and the first and second bicuspids. In addition the permanent second molar also erupts during this time.
Thumb sucking or finger sucking is the habit that frequently produces anterior open bite. thumb sucking is a spontaneous activity that develops soon after birth. Between birth and 3 months of age, its intensity increases until age 7 months and then usually decrease with the development of other sensory and motor activities. An open bite in most cases is associated with unbroken, constant thumb sucking habit resulting in displacement of anterior alveolus and teeth.
Tongue thrusting is when the tongue takes an abnormal anterior position during swallowing. It may cause protrusion and diastema formation to maxillary teeth. in more severe cases the tongue protrudes between the maxillary and mandibular anterior teeth during swallowing. (producing anterior open bite).
this is difficult to treat.
Abnormal Labial frenum - The maxillary labial frenum is frequently believed responsible for midline diastemas . The frenum does normally appear lower with growth patterns demonstrating less vertical dentolaveolar growth. Cutting or removal of the fibrous frenum does not ensure space closure. Space closure should be delayed until after cuspid eruption because space closure often occurs spontaneously at that time.
Skeletal Growth problems- anterior crossbite may be associated with a skeletal discrepancy and is caused by a true class III malocclusion. It may be an acquired muscular reflex pattern of mandibular closure to a pseudo-class III malocclusion. This is usually not a isolated tooth.
REF: Wei HY., Pediatric Dentistry Total Patient Care . Lea & Febiger Publishing Co. 1988 471-481.
The leeway space in the mandible is greater than that in the maxilla by approximately half a tooth. This difference allows the permanent mandibular first molar to drift mesially from a flush terminal plane to a Class I relationship.
Both statements are TRUE.
Both statements are FALSE.
The first statement is TRUE, the second is FALSE.
The first statement is FALSE, the second is TRUE.
Best answer is a
Leeway space s described by Nance in 1947, is defined as the difference between the sum of the mesial distal width of C, D, and E in succeeding permanent teeth (#,4, and 5’s). The maxillary provides 0.9mm/side and the mandibular arch provides 1.7mm /side. The second statement therefore is also true.
Class Notes PEDO Notes from Capt. Bookwalter 1997. 455.
88. After orthodontically extruding a tooth, how long do you hold it in retention before prosthetically restoring the tooth?
a. 3-4 weeks
b. 8-10 weeks
c. 4 months
d. 6 months
e. 1 year
Several authors disagree on this:
Simon et al: JADA vol. 97 7/78 p. 17 say 8-12 weeks
ortho notes from CDR Masceroni say 8-12 weeks ortho notes 240.7 page 1
Nappen: Journal Pros Dent vol 61 5/89 p. 549 12 weeks
Oesterle: JADA vol 122 7/91 p. 193 8 weeks
Zyskind et al: Quintes. Vol 23 number 6 1992 p. 398 6 months
Johnson: JADA vol 121 10/90 p. 476 6 months
As usual your guess is as good as mine: the typical misguided answers that we’ve seen through out this test.!!
89. Premature loss of primary canines leads to:
a. Mesial drift of posterior teeth
b. Distal drift of the incisors
c. Root resorption
d. Supraeruption of opposing tooth
e. Any of the above
According to our Pedo notes “SPACE MAINTENACE NDS 222” page 1
A. 2. e) (2) premature loss of mandibular cuspids (regardless how) will result in lingual collapse of mandibular incisors
B. 2. Canine Space
a) Premature loss of primary canines (mandible) may cause deepening of bite and midline shift and super eruption of anterior segment.
B) May allow posterior segment to move mesially.
According to my tally that leaves : a, d, and possibly b as answers depending on how you read “distal drift”.....
That makes the answer “E” by default!!!
Gotta love those “clever test makers...eh!!??
90. Incisor liability in the maxillary arch is_____ mm and ____mm in the mandibular arch.
a. 6.0, 7.6
b. 6.7, 6.0
c. 7.6, 6.0 by definition from pedo notes p. 5 incisor liability (Black)
d. 7.2, 6.7
e. 7.6, 6.4
91. Which is used to assess skeletal imbalance between the maxilla and mandible?
Definition: Angle formed by the intersection of the Frankfort horizontal and the mandibular planes.
Use: Another measure of mandibular growth direction. As the FMA increases, the amount of vertical growth exceeds horizontal growth and the chin is more posterior and vice versa.
Definition: Angle formed by the intersection of planes sella-nasion and nasion-pt A.
Use: Measures the relative anteroposterior relationship of the maxilla to the anterior cranial base.
Definition: Angle formed by the intersection of sella-nasion and nasion-pt B.
Use: Measures the anteroposterior relationship of the mandible to the anterior cranial base.
Definition: Angle formed by the intersection of pt A and pt B planes.
Use: This angle relates the maxilla to the mandible anteroposteriorly. A high value indicates a maxilla which is forward, or a mandible which is retrognathic or a combination of both.
Definition: Angle formed by the intersection of the sella-nasion plane and the mandibular plane.
Use: Angle is a means of assessing mandibular growth direction. High values result from a short ramus, a long anterior face, are associated with anterior open bites and vertically growing facial patterns. Low, or flat values result from a long ramus, a short anterior face, are associated with deep anterior overbites and horizontal growth patterns.
Ref. Cephalometrics from Orthodontic Manual given out by Dr. Maskeroni
92. The fixing process removes the unexposed and undeveloped silver bromide crystals from the film emulsion and is activated by the:
a. alkali agent and sodium sulfite
b. acetic acid and ammonium thiosulfate
c. reducing agent and acetic acid
d. acidic agent and potassium bromide
e. bromic acid and hydroquinone
Developer: amplifies latent image
Fixer: removes unexposed/undeveloped silver bromide crystals from film emulsion
Hydroquinone - reducing agent
Thiosulfate (sodium or ammonium) - clearing agent
Sodium Sulfite - preservative
Sodium Sulfite - preservative
Potassium Bromide - anti fog
Potassium alum - hardener
Sodium carbonate - alkali
Ref. Class notes
93. BW X-rays reveal 2 new interproximal carious lesions to be restored in a 21 year old female patient. ADA recommends that the next exam with BWs should be in ____months.
Primary dentition (before 1st permanent molars)
Transitional dentition (after 1st permanent molar)
Clinical caries or high risk factors for caries
6 months or until no caries evident
6 months or until no caries
Ref. American Academy of Pediatric Dentistry Reference Manual 1993
A boy who is 7 years 10 months old and who has an otherwise normal occlusion has the upper right central incisor in complete lingual relation to the lower incisors. The upper left lateral incisor is just beginning to erupt. Which of the following should you do?
a. Wait until full eruption of both lateral incisors before treating.
b. Wait until eruption of all permanent teeth before treating.
c. Delay treatment because the condition may correct itself.
d. Correct the lingually malposed central incisor immediately
e. Extract the upper deciduous lateral incisors immediately
An untreated inlocked or lingually related maxillary central will result in loss of arch length, and eventual stripping of the tissue and pocket formation. Complete anterior x-bite in the primary dentition may indicate a skeletal growth problem and a developing Class III malocclusion. Anterior x-bite of one or more of the permanent incisors may be evidence of a localized discrepancy, which should be treated in the mixed dentition state as soon as it is discovered. Delayed treatment can lead to serious complications such as loss of arch length. Unsightly wear facets may also develop on the incisal and labial surfaces of the involved maxillary incisors. Anterior x-bite may result from labially positioned supernumerary teeth creating lingual deflection of an incisor. Other deflections include retained primary teeth (pulpless primary teeth do not always undergo normal root resorption), trauma to primary teeth (with displacement of the permanent successor), & arch length deficiency (esp in maxillary lateral incisor area). When insufficient space exists, consultation with an orthodontist may be required prior to treatment. McDonald & Avery, 6th ed pp. 745-47
95. With the Angle Class II Division II occlusion, which of the following best applies to the maxillary central incisors?
a. normal inclination, the laterals are in linguoversion
b. normal inclination, but bodily forward of the mandibular incisors
c. normal inclination, but bodily behind the mandibular incisors
d. in labioversion
e. slightly in linguoversion
Class II, Division I
The mesiobuccal cusp tip of the maxillary first molar is positioned anterior to the buccal groove of the mandibular first molar. The sagittal molar relationship of these patients is referred to as a disto-occlusion as opposed to a neutro-occlusion for Class I patients. This type of malocclusion is often characterized by excessive overjet in the anterior region. Unlike Class I patients, these patients often exhibit downward growth, abnormal muscle pressure, and a convex--soft and hard-- tissue profile.
Class II, Division II
The molar position is similar to Class II, Div I except the excessive overjet is not seen. The anterior relationship is characterized by lingual tipping of the central incisors and labial flaring of the lateral incisors. Whereas the CL II Div I pt shows a weak chin, these pts tend to have a square jaw, skeletal deep bite, and a short lower facial height.
McDonald & Avery, 6th ed pp. 694-5.
96. One hour ago a three year old child fell and intruded (AKA # E & # F. How would you manage this situation?
a. Extract E & F to protect the permanent teeth and place a space maintainer.
b. Reposition E & F place an acid etch splint and maintain it for 3-4 weeks.
c. Reposition E & F, place a nonrigid (nylon line/ resin) splint and maintain it for 10-14 days.
d. Observe and wait for re-eruption within 6 weeks.
e. Reposition E & F and keep patient on soft foods for 10 days.
The intrusion by forceful implication of maxillary anterior primary teeth is a common occurrence in children under 3. Frequent falls and striking the teeth on hard objects may force the teeth into the alveolar process to the extent that the entire clinical crown beomes buried in bone and soft tissue. Although there is a difference of opinion regarding treatment of injuries of this type, it is generally agreed that immediate attention is given to soft tissue damage and intruded primary teeth should be observed & with few exceptions, no attempts made to reposition them after an accident. Normally the developing permanent incisor tooth buds lie lingual to the roots of primary central incisors. If intrusion occurs labially, confirmation with a lateral radiograph with extraction is required.
McDonald & Avery, 6th Ed pp. 538-42.
97. Which of the following are considered to be disadvantages of sterilization with ethylene oxide?
1. Lack of dependability
2. Corrosion of instruments
3. Length of time required for sterilization
4. Ventilation is required
a. 1 and 3
b. 1 and 4
c. 3 and 4
d. 2,3 and 4
Dentists’ Desk Reference: Materials, Instruments, And Equipment, 2nd Edition, American Dental Association, 1983, pg 396. Almost any material, including any handpiece, can be sterilized with ethylene oxide. The cycles of 2 to 8 hours are long for routine use but it serves as a good backup. Some plastics are degraded on repeated exposure. The Ethylene oxide sterilized must be operated outside or where air is evacuated to the outside and not recirculated
98. The major disadvantage of computerized tomography is
a. production of excess radiation.
b. inability of patient to remain still.
c. difficulty of interpretation.
d. informational limitations.
e. little definition of soft tissues.
Goaz, PW, White, SC, Oral Radiology, 3rd Edition, Copyright 1994, Mosby-Year Book, Inc., 276-279.
There are several advantages to CT over conventional film radiography and film tomography. First, CT completely eliminates the superimposition of images of structures superficial or deep to the area of interest within the patient. Second, because of the inherent high contrast resolution of CT, differences may be distinguished between tissues that differ in physical density by less than 1%; a 10% difference in physical density is required to distinguish between tissues by conventional radiography. Third, data from a single CT imaging procedure consisting of multiple contiguous scans of a patient may be viewed as images in the axial, coronal, or sagittal planes depending on the diagnostic task, referred to a multiplanar imaging.
These images, however, remain two-dimensional and require a certain degree of mental integration by the viewer for interpretation, which limitation has led to the development of computer programs to reformat date acquired form axial CT scans into three-dimensional images (3D-CT).
99. Primary teeth begin to calcify between the ________ and ________months in utero.
McDonald states that calcification of the primary teeth beginning at approximately 14 weeks.
100. Tetracycline ceases to result in aesthetically significant dental discoloration after ______ years of age.
The primary teeth begin to calcify at approximately 14 weeks in utero. Since TCN crosses the placenta the primary teeth can be affected by administration of the drug. By the age of 9 the permant teeth excluding the second and third molars are formed so the esthetic teeth would no onger be affected.
1. is the sequential re-entry and reuse of previously employed instruments within the canal
2. permits the gradual smoothing and tapering of the prepared canal
3. eliminates the possibility of dentin mud from being packed into the end of the canal
4. maintains the patency of the apical foramen
e. all of the above
Recapitulation- The follow-up cleaning action of returning full length with a smaller sized instrument to remove the dentinal debris that forms as the body of the canal is being shaped with larger instruments.
……….returning frequently with the first instrument to break up and remove any chips or debris forming in the apical curve.
The advantages of this technique are: (1)less possibility of perforation or ledging, (2)uniform enlargement of irregularly shaped canals, (3)better debridement, (4)savings in operator time, and (5)obturation with gutta percha in severly curved canals, with the exaggerated taper permitting greater compressipon of the gutta percha in the apical portion of the canal.
Copious irrigation should accompany the filing, as should recapitulation with the smaller apical instrument, to ensure that the cavity is not clogged with debris.
Ref: Endodontics, Ingle & Beveridge, 2nd Edition 1976, p. 199-204
102. Internal resorption is most likely the result of:
a. a necrotic pulp
b. an acute pulpitis
c. a reversible pulpitis
d. an irreversible chronic pulpitis
e. a hyperplastic pulpitis
The following information was collected from a handout provided by CDR J Pastor 31 Oct 96.
Irreversible Pulpitis: Localized areas of necrosis that cannot be repaired or walled off. It spreads throughout the pulp by causing inflammation in adjacent areas.
Probably caused by trauma
Can be transient or progressive; transient form is shallow and selflimiting
Progressive form continues after loss of odontoblasts and predentin
Requires continued stimulation by bacteria provided by infected, necrotic pulp tissue coronal to resorptive lesion
Perforation can occur, and communication with the PDL space
Wedenberg Studies on Internal Resorption
An excellent series of four articles were written by Wedenberg regarding the mechanisms involved in internal resorption. Two of these were of particular interest:
Wedenberg C, Lindskog S. Experimental internal resorption in monkey teeth. Endod Dent Traumatol 1985; 1: 221-7.
* Pulps were exposed mechanically. Half were injected with an antigenic agent and sealed; half remained open to salivary contamination.
* Histological evaluations 1 to 10 wk later revealed sealed teeth had no bacteria. Inflammation decreased after 6 wks. Transient resorptive activity, with early healing evident
* Unsealed teeth were loaded with bacteria in dentinal tubules. Macrophage-like cells attached and spreading over dentin surface, with progressively increasing inflammatory changes noted. Chemical markers showed resorptive activity.
* Suggests that progressive internal resorption requires continuous stimulation bv infection.
Wedenberg C, Zetterqvist L. Internal resorption in human teeth - a histological, scanning electron microscopic, and enzyme histochemical study. J Endodon 1987; 13: 255-9.
* Human primary and permanent teeth, extracted because of progressive internal resorption, were studied under light microscopy, SEM, and histochemically.
* Trauma and infection were included in hx of all teeth.
* All but two contained bacteria in dentin tubules or coronal pulp space.
* Mineralized tissue resembling bone or cellular cementum outlined pulp cavity.
* Connective tissue had replaced pulp, and resembled the PDL tissue it was contiguous with.
* Internal resorption characterized by large multinucleated dentinoclasts in resorption lacunae on the pulpal dentinal surface, with chemical markers indicating resorptive activity.
* Suggested that internal resorption cannot take place unless normal pulp tissue is replaced by periodontal-like tissue.
Diagnosis of Internal Resorption
Discovery is primarily by radiographic means
Symptoms are inconsistent; may not be painful
"Pink spot" may occur with resorption involving the crown
Radiographic appearance: sharp outline, with outline of root canal lost in lesion; remains centrally located with changes in horizontal angulation
Root canal therapy will interrupt process
Perforating lesion may require surgical repair or orthodontic extrusion
*Stamos DE, Stamos DG. A new treatment modality for internal resorption. J Endodon 1986; 12: 315-19.
Combination of ultrasonic instrumentation and injection-molded thermoplasticized GP with additional vertical condensation shown to be an effective method for treatment of internal resorption defects.
103. Thermoplasticized gutta-percha:
a. requires heating the filling material to 180C
b. uses needle sizes of 18 gauge and larger
c. can be used to backfill canals filled at the apex by other canal filling techniques
d. rarely causes overfilling
e. is the most reliable method for obtaining apical seal
The following information was collected from CAPT T.L. Walker’s handout of 23 October 1996, titled Obturation of the Root Canal System
Thermoplasticized Gutta-Percha Technique
1. Obtura System
High temperature (160 C)
** Obtura II -- Texceed Corporation
Yee, et. al. J Endodon 1977
Three dimensional obturation of the root canal using
injection-molded, thermoplasticized dental guttapercha
- Control unit
- Delivery unit
- Applicator tip
c) Clinical application
- Internal resorption
- Severe root curvature
- Periapical surgery
Flath and Hicks
J Endodon 1987
Retrograde instrumentation and obturation with new
2. Ultrafil System
Low temperature (70 C)
Michanowicz and Czonstkowsky J Endodon 1984
Sealing properties of an injection-thermoplasticized low temperature (70 C) gutta-percha: a preliminary study.
- Gutta-percha cannules
c) Gutta-percha cannule
- reservoir of gutta-percha
- 22 gauge needle
f) Clinical application
LaCombe, Campbell, Hicks, and Pelleu
A comparison of the apical seal produced by two
thermoplasticized injectable gutta-percha techniques
J Endodon 1988
"Lateral condensation resulted in less linear dye leakage than either low- or high-temperature thermoplasticized injectable g.p. and resulted in fewer overextensions than the low-temperature thermoplasticized injectable g.p. technique."
104. The microorganisms most likely to be present in greater numbers in a symptomatic infected rooot canal are:
Correct answer is D. Bacteroides
A summary of a series of bacteriological studies of endodontic infections was presented in the article Bacteroides spp.in dental root canal infections, Endodontic Dental Traumatol 1989; 5: 1-10. All infections were mixed infections dominated by usually by anaerobic bacteria. Four to six diferent species werre present in most canals. Species of the genus Bacteroides were found more frequently than species of any other genus
Aerobic organisms dominate the non-infected root canal. (Staphylococci).
Streptococci (facultative aerobe) is commonly found in odontogenic infections. With long term infection in the tissues Actinomyces is frequently found.
105. The most effective cutting action of Hedstrom files is recommended with which motion?
a. penetration only
b. penetration and rotation
c. rotation and retraction
d. retraction only
e. rotation only
correct answer is` d, retraction only
The various files used for endodontic treatment are:
Reamer (K-type) - twisted from square or triangular blank
0.8. to 0.28 flutes/mm
used with reaming and counter-rotational motion
File (K -type) - twisted from square blank
1.97 to 0.88 flutes/mm
used with a rasping motion
File (H-type or Hedstrom) made by machine grinding
helical angle near 90 degrees
used with a pulling motion (circumferentail filing)
Design improvements - cross-sectional design -triangular or rhomboid
H-type hybrids - Unifile, S-file, Flex-R, Flex-O
Endodontic classnotes with ADA Specification No. 28 which established standards for the !. diameter and taper of instruments
2. Incremental size increases between instruments
3. Numbering systems for instruments
106. Which of the following mandibular teeth most frequently has multiple canals?
c. first bicuspids
d. second bicuspids
correct answer is b. incisors 40 % incidence of 2 canals
a. cuspids incidence of 2 canals 6%
c. first bicuspids incidence of 2 canals 6.5%
d. second bicuspids incidence of 2 canals 1.5
1. Involves burring through the cortex and cancellous bone apical to the suspected root end.
2. Is indicated when drainage can not be obtained through the pulp system.
3. Required the use of antibiotics.
4. Is need when a soft fluctuant mass is present.
5. Tooth still requires obturation of the root canal system
The entry point can be either apical to the root end or as Gutman and Harrison recommend in the midroot in interdental bone and access the periapical area with a # 45 K type file. This eliminates the worry about hitting the tooth root with a bur.
Cortical trephination is indicated when a patient presents with moderate to severe pain, but with no intraoral or extraoral swelling and an inability to accomplish apical trephination. Possible reasons would be broken instrument posts ledged or severely curved canals.
Antibiotic therapy for the medically uncompromised patient is not indicated. Pain is the problem not infection. Any infection is a local problem not a systemic one note the indications -No Swelling.
Wait about one week before completing definitive endo therapy which would be standard NSRCT.
Reference - Gutman and Harison Surgical Endodontics
108. The following is true concerning pulpal innervation:
a. thermal testing relies mainly on the fast conducting A-delat fibers
b. proprioception in the pulp is conducted by A-beta fibers
c. the lingering, throbbing pain of pulpitis is due mainly to the stimulation of the C fibers
d. a and c
e. all of the above
speed of impulse, m/sec
Afferent fibers for touch, pressure, proprioception, vibration (mechanoceptors)
Afferent fibers for pain and temperature
Sharp, pricking and unpleasant but bearable (fast and momentary)
Visceral afferent fibers; preganglionic visceral efferent fibers
Afferent fibers for pain and temperature; postganglionic visceral efferent fibers
Throbbing, aching and less bearable; lingering and extremely unpleasant sensation
Ref. Weine FS. Endodontic Therapy Fourth Edition
109. The Weine classification of a root canal system having two canals which combine to one canal exiting periapically is:
a. Type I
b. Type II
c. Type III
d. Type IV
e. Type V
The following information was provided by the Long Course in Endodotics:
CLASSIFICATION OF THE ROOT CANAL SYSTEM -(WEINE)
1. Type 1: single canal from the pulp chamber to apex (one orifice, one canal, one foramen)
2. Type II: two canals leaving the chamber and merging to form a single canal short of the apex (two orifices, two canals, one foramen)
3. Type III: two separate and distinct canals from chamber to apex (two orifices, two canals, two foramen)
4. Type IV: one canal leaving the chamber and dividing into separate and distinct canals (one orifice, two canals, two formaen)
110. The “Balanced Force” technique. Advocated by Roane, includes all of the
a. Flex-R files used sequentially
b. instrumentation to the periodontal ligament
c. clockwise/counter-clockwise filing motion
d. essentially a step-back preparation technique
e. flaring of canals with Gates-Glidden drills is recommended
Correct answer is d
Balanced force concept using Flex-R-Files. After 12 years of experimentation , Roane and Sabala introduced their Balanced Force concept of root canal preparation. The concept came to fruition, they claim, with the introduction of new K-type file design the Flex-R-File (Rhomboid). Initially, the authors developed a reaming action using clockwise insertion followed by counterclockwise action.
Essentially the whole preparation is a step-down technique ( not a step-back preparation) in nature beginning with flaring of the coronal and mid-thirds of the canal with Gates Glidden drills sizes 1 through 6 ( I would not use a 1 because the y have a tendency to separate). This essentially increases the radius and decreases the arc or closure of the canal, thus making it straighter and more accessible to reaming instruments.
At this point, the balanced force instrumentation begins. It involves placement, cutting and removal using only rotary motions. Insertion is done with half-turn clockwise motion with slight apical pressure. “Cutting is accomplished using counterclockwise
rotation,” again with apical pressure “ adjusted to match the file’s strength, i.e. very light for fine instruments and heavy for large instruments. Clockwise which “sets” instrument, should never exceed 180 degrees; otherwise the instrument will start to unwind. Counterclockwise rotation, with apical pressure, is 120 degrees or greater. This “rewinds the instrument and enlarges the canal to the full instrument diameter, a size that was established by the counterclockwise twisting during manufacture. In this way ( clockwise insertion and counterclockwise cutting and removal), the instruments advance toward the apex. Continuing this technique, the clinician enlarges the canal by advancing up the scale of larger and larger instruments
The noncutting tip and first blades of the Flex-R-Files prevents the instruments from gouging into the curved walls allowing the file to hug the inside of the curve and prevent tip transport toward the external curve.
When enlargement has been accomplished, a final clockwise cleaning rotation is used to load canal debris into flutes and to elevate that debris away from apical foramen. Irrigation follows
Roane firmly believes in enlarging the apical area to sizes larger than generally recommended- up to size 80 in a single canal, for example and size 45 for multiple canal teeth. These sizes are not absolute, of course, and final sizing depends upon root bulk and/or fragility, or the extreme curvature of a canal . He also believes in carrying the preparation through to full length,” the radiographic apex of the root. He purposely violates the apical area and rarely gets flareups. For examples, the No. 30 instrument is carried to full root length and larger instruments are stepped back from that -No 40 at 0.5 mm back, No 45, at 1.0 mm back and back up the canal until the Gates Glidden preparation is reached. NaOCl irrigation is used.
Step back or Step down
Step back starts at the apex with fine instruments and working one’s way back up the canal with progressively larger instruments- the serial or step back technique; or the opposite- starting at the cervical orifice with larger instruments and gradually progressing toward the apex with smaller and smaller instruments- the step down technique, also called “crown down” filing.
REF: Ingle, JI and Bakland, LK; ENDODONTICS , 4th ed, Williams and Wilkins, pp 208-209. 199.
111. The formation of cysts around nonvital teeth is usually the result of
a. the overgrowth of pulp
b. the stimulation of the epithelial cell rests
c. the overgrowth of the epithelium from marrow spaces
d. traumatically induced intermedullary hemorrhage
e. stimulation from pulpal fibroblasts
Correct answer is b.
Formation of cysts
One of the normal components of the lateral and apical periodontal ligaments is the epithelial rest of Malassez. The term rests is misleading in that it evokes a vision of discrete islands of epithelial cells. It has been shown that these rests are actually fishnet-like, three dimensional network of epithelial cells . in many periapical lesion the epithelium is not present and is presumed to been destroyed. If these rest remain, they may respond to stimulus by proliferating in an attempt to wall off the irritants.
The epithelium is surrounded by chronic inflammation, and this lesion is termed an epitheliated granuloma ( a granuloma containing epithelium);. The epithelium continues to proliferate in an attempt to wall off the source of irritation ( i.e. bacteria and products from the apical foramen). The term bay cyst has been coined for the microscopic representation of this situation. This chronic inflammation lesion that has epithelium lining the lumen, but the lumen has a direct communication with the root canal system. It is not a true cyst, because a true cyst, is a three dimensional , epithelium-lined cavity with no communication between the lumen and the canal system.
When periapical lesions are studied in relation to the root canal, completely epithelial lined cavities are found. These are termed true cysts. There has been some
confusion in the diagnosis when lesions are studied only on curetted biopsy material. Since the tooth is not attached to the lesion, orientation to the apex is lost. Therefore the criterion used for diagnosis of a cyst is “strip of epithelium that appears to be lining a cavity. It appears that curreting the bay cyst and a true cyst could give the same microscopic diagnosis: a bay cyst could be sectioned in such a way that it could resemble or give the appearance to a true cyst.
The distinction between a bay and a true cyst is important from standpoint of healing. Endodontists state that they heal some cyst with nonsurgical root canal treatment, whereas surgeons state that cyst have to be surgically excised. It may be that true cysts have to be surgically removed, but bay cysts that communicate with the root canal system may heal with non-surgical root canal therapy. Since the root canal therapy can directly affect the lumen of the bay cyst, the enviromental change may bring about a resolution of this lesion. The true cyst is independent of the root canal system, so conventional therapy may have no effect on it. This would explain the discrepancy between the endodontic and surgical opinions on treatment of cysts. The formation of cysts and its progression from a bay cyst to a true cyst occurs over time. Vaulderhaung showed in monkeys that no cysts were formed until at least 6 months after the canal contents became necrotic. Thus the longer a lesion has been present the greater the chance of becoming a true cyst. The prevalence of true cysts is probably less than 10%.
REF: Pathways of the Pulp , Cohen, S, and Burns R C; Mosby Publishing Co. Sixth edition page 352.
112. Agents used within the pulp chamber to bleach endodontically treated teeth include
1. Superoxol (30% hydrogen peroxide)
2. sodium hypochlorite
3. sodium perborate
4. hydrochloric acid
a. 1 and 2
b. 1 and 3
c. 1 and 4
d. 2 and 3
e. 3 and 4
Correct answer is b.
Agents and techniques for bleaching discolored teeth have changed little in the last 30 years. The two bleaching agents most commonly used are Superoxol ( 30 to 35 percent hydrogen peroxide) and sodium perborate. Both are oxidizing agents. Superoxol has about twice the available oxygen as sodium perborate. This property makes it more reactive during bleaching and likely to burn soft tissue.
Superoxol is heated directly within the pulp chamber in the thermocatalytic bleach or mixed with sodium perborate and sealed in the pulp chamber to form the walking bleach. Sodium perborate may be mixed with water as a less reactive type of walking bleach.
RESORPTION- Harrington and Natkin were the first to report a possible relationship between intracoronal bleaching of pulpless teeth and external cervical root resorption . Other studies found from 0 to 6.9%. it could occur in as many as one of every 12 teeth bleached.
Originally it appeared that the combination of Superoxol and heat was initiating the resorption. However, in case reports subsequently published, two different characteristics were found in every instance of resorption. One, the teeth became pulpless before the patient reached age 25. Two no barrier had been placed between the endodontic filling material and the pulp chamber. Therefore, it appears that the age of the patient at the time the tooth became pulpless and the presence of a barrier may be as important as the type of bleaching agent and the use of heat during bleaching.
In ten percent of all teeth, dentinal tubules communicate between the root canal system and the periodontal membrane space through defects at the cementoenamel junction (CEJ). If the patient is young when the tooth becomes pulpless, the tubules will remain patent since formation of sclerotic dentin halts. These open tubules represent a conduit for bleach solution to reach the periodontal ligament from the root canal system.
Since the dentinal tubules are orientated incisally clinicians have advocated bleaching agents be placed apical to the labial CEJ to bleach the cervical third of the crown. Three factors, bleach placed apical to the CEJ, patent dentinal tubules in young pulpless teeth, and a defect in the CEJ may combine to allow the bleaching agent to diffuse into the periodontal ligament. An inflammatory reaction be initiated, resulting in external cervical root resorption.
Clinicians have no control over the patient’s age when tooth becomes pulpless. They do have control over location, shape and material of a bleach barrier between filling material
and the pulp chamber. The labial CEJ has been suggested as the guide to determine the barrier location. The CEJ is not level but rather curves in an incisal direction on the proximal sides of the tooth. If a flat barrier is placed, the proximal tubules are unprotected by the barrier material. This critical proximal area is where cervical root resorption begins.
In preliminary studies IRM, zinc oxyphosphate, and dentin sealants failed to create satisfactory barriers. However, Cavit and light cured glass ionomer cements may offer promise future barrier materials. More research is being cone to determine the best barrier material.
REF: Pathways of the Pulp , Cohen, S, and Burns R C; Mosby Publishing Co. Sixth edition page 593-595
113. A 20 year old patient presents two weeks after sustaining a traumatic blow to a maxillary central incisor. The tooth is asymptomatic and gives a normal vital response to heat, cold and electrical pulp testing. A radiograph shows a horizontal fracture on the apical third of the root with segments in close apposition. The tooth exhibits Class II mobility. The initial treatment is to:
a. relieve the occlusion and evaluate in one month
b. initiate endodontic therapy using calcium hydroxide in the canal system
c. relieve the occlusion and stabilize the tooth
d. perform endodontic therapy and remove the root fragment
e. no treatment indicated unless crown becomes discolored
The first response is close but only addresses the occlusion portion of the problem. The tooth still needs to be stabilized. The second answer would be a possibility if there were a radioluscency at the apex or the tooth tested non-vital to all tests and had a radioluscency. Although it must be noted that teeth with root fractures may not exhibit the “normal” responses expected on vitality tests. The fourth answer would be a possibility if the criteria mentioned above was met along with the distal root segment not being in close approximation to the remainder of the root. Then a surgical approach would warrant an apicoectomy to remove the affected segment. The last answer would be OK if the tooth were not mobile and had no occlusion opposing it and had no way of placing any pressure on it.
C is the correct answer as from 20 -40% become non-vital after a root fracture. More often than not, with the proper treatment (answer C), the tooth with heal without incident by either : calcific, connective tissue, combination bone and connective tissue, or non-union with granulation tissue, approximating the two pieces of root tip.
PATHWAYS OF THE PULP : Cohen and Burns, 5th edition, 1991, pp462-470
PRACTICAL ENDODONTICS, A CLINICAL ATLAS : Besner, Michanowicz, A., and Michanowicz, J. , Mosby, 1994, pp267-269.
114. A patient presents with severe spontaneous pain of 36 hours duration from the maxillary right first molar. The tooth was restored 3 days ago with a large MOD amalgam and a calcium hydroxide base. The tooth gives a positive response to the electric pulp tester and is not sensitive to heat. Based on this evidence, the most probable diagnosis would be:
a. acute apical periodontitis
c. irreversible pulpitis
d. reversible pulpitis
e. acute periradicular periodontitis.
After much research, I came to the conclusion that “a and e” were essentially the same answer and therefore could not be correct. Besides, this is a periradicular diagnosis and would probably involve some sort of percussion sensitivity, which is not even addressed in this question. Hyperocclusion would also be diagnosed by percussion sensitivity, but would not have any other symptoms associated with it as far as irreversible/reversible pulpitis. Which leads us to irreversible pulpitis, “Seltzer believes that the most definitive factor in irreversible pulpitis is the presence of an intrapulpal abscess. This diagnosis is based on a history of previous pain (moderate to severe), no response to pulp tests, or vitalometer tests differing markedly from those of the control teeth. In addition, the presence of spontaneous severe pain or a prolonged response after thermal testing usually indicates irreversible pulpitis.”
Gutmann says that, “pulpal pain is common after restorative procedures.” That after several weeks the pain should reside, if not then to reconsider the diagnosis as irreversible pulpitis.
Therefore, the correct answer is “d” based on the criteria for irreversible pulpitis. If the question were worded that the patient had previous pain in the same tooth, or had negative results to the pulpal tests, than irreversible pulpitis would be correct.
PATHWAYS TO THE PULP : Cohen and Burns, 5th edition, Mosby, 1991, pp361-362
Seltzer, S: Classification of pulpal pathosis , Oral Surgery 34:269, 1972.
PROBLEM SOLVING IN ENDODONTICS (prevention, identification, and management) : Gutmann, Dumsha, and Lovdahl, Year Book Medical Publishers, 1988, pp 124-127. 115. For which of the following complications may an apicoectomy become the treatment of
1. When the anatomy of the canal system is intricate and complex
2. When an iatrogenic perforation occurs in the apical 1/3 of the root
3. When there is external root resorption near the apex
4. When there is an irremovable canal obstruction
a. 1, 3
b. 2, 4
c. 1, 2, 3
d. 2, 3, 4
e. All of the above
**(according to Dr. Robert Gregg’s rules of test taking, “if a number appears several times in your choices for answers, than it is probably in the correct choice”, and since 2 and 3 appear the most, but do not have a correct answer as such, then “d” becomes the correct answer)**
According to : Besner, & Michanowicz(x2), PRACTICAL ENDODONTICS A CLINICAL ATLAS, Mosby, 1994, page 227:
“ Indications for apicoectomy:
1. Calcified canals with lesions.
2. Teeth with constant discomfort and persistent drainage.
3. Teeth with post and cores that cannot be treated nonsurgically.
4. Perforations and teeth that were ledged and unmanageable with conventional endodontics.
5. Teeth with curved roots, i.e., S-shaped root apices not negotiable with conventional
6. Incomplete apical formation that will not respond to apexification.
7. Root resorption-external resorption that altered the root canal, chamber, or apex.
8. Excess overfilling of the root canal apex with persistent exacerbation.
9. Root fractures associated with periapical lesions.”
Therefore answer “1” suggests that the canals are intricate and complex but not necessarily non-treatable by NSRCT...you know much our T-2 ENDO resident brothers and sisters “love “ to do those third molars!! So that leaves 2, 3, 4 as the answers, as per the above criteria.
116. Which of the following are true concerning ultrasonic endodontic instrumentation?
1. enhance debridement and disinfection of canals due to mechanical, chemical and physical effects of process
2. works particularly well in small curved canals due to efficient irrigant flow
3. can be used to assist in retrieval of broken instruments, silver points and foreign objects
4. should be used in combination with hand instruments when used properly
5. recommended for use in treating teeth with wide open apexes
a. 1, 3, 4
b. 1, 2, 4, 5
c. 1, 2, 4
d. 3, 4, 5
e. all of the above
Ultrasonic vibration is unparalled in its ability to enhance cleaning with irrigants. Because the cleaning effects of ultrasonics are most ideal when the energized instrument is loose in the canal, it is probably best used after canal shaping is completed.
Ultrasonics are most effective in apical third of canal because of the greater amplitudes of vibratory movement at the file tip.
Does not work well in small curved canals due to restriction to the apical third and confined space.
If used in wide open apexes, will not be confined to canal space and will cause damage and increased inflammation to periapical tissues.
Ref. Cohen S Burns RC Pathways of the Pulp Fifth Edition
117. The standardization of root canal instruments provides that:
1. instruments #10 to #60 are uniformly color coded and the numbers advance by units of five
2. the file number represents the diameter of the file in hundredths of a millimeter at the tip
3. the length of the working blades of files are available in 21, 25 and 30 mm lengths
4. the diameter at the tip of a #30 file is .30 mm .02 mm
5. starting with file #10 to #45, the color code is purple, white, yellow, red, green, blue, black and white
a. 1, 2, 3, 4
b. 2, 3, 4, 5
c. 1, 3, 4, 5
d. 1, 2, 4
e. all of above
(Insert Fig 13-7 and Table 3-1 from notes)
Ref. Endo class notes
118. The rationale for using Ca(OH)2 to repair perforating internal resorption is that:
It reduces the inflammatory response in an oral fluid environment
it promotes osteoblastic activity, stimulating repair
its alkaline pH spreads through the dentin after placement in
an acid pH environment is created causing hard tissue deposition
Used first by BW Hermann in 1930, Ca (OH) 2 exact mode of action is unknown. In apexification, healing results from the stimulation of undifferentiated mesenchymal cells in the apical PDL. In a pulpotomy, it stimulates vital pulp tissue cells to produce reparative dentin. As long as there is no communication with oral fluids, Ca (OH) 2 will reduce inflammation and promote healing. Due to its high pH, it is antibacterial and it makes osteoclastic activity impossible. The alkalinity spreads through the dentin and once in the pulp chamber, reverses the acidic enzymatic resorptive reaction and allows the deposition of hard tissue. Cohen's Pathways of the Pulp 5th ed. p. 512.
119. Which of the following mechanical objectives in shaping the root canal are correct?
to make the canal narrow apically with the narrowest cross sectional diameter at its terminus p. 179 Cohen
to have the conical canal preparation exist in many planes
to obtain direct line access to apical foramen p. 183, Cohen Schilder technique
to leave the apical foramen as small as possible p. 184 Cohen
to develop a continuously parallel form in the canal preparation
all of the above
120. Irrigation during hand instrumentation with NaOCl is helpful because it
keeps the files from becoming too hot
aids in canal disinfection by washing bacteria and substrate from the canal
dissolves soft tissue and lubricates the canal p. 178, 411 Cohen
prevents the tooth from dehydrating and fracturing under the rubber dam
adds moisture to soften dentin and makes it easier to cut
all of the above
121. The most frequent cause of the loss of an endodontically treated tooth is
poor apical seal
a fractured root
failure to provide an adequate restoration
failure to obturate a lateral canal
undetected perforation of the root canal
Abbott PV, ANNALS OF THE ROYAL AUSTRALASIAN COLLEGE OF DENTAL SURGEONS, 1996 Apr; 13:79-98. Failures, Disasters And Catastrophes—A Hypothetical Endodontics.
... now points to endodontic failures being largely a consequence of failures of the coral restoration rather than being due to the root canal filling itself.
Cohen, S, Burns, RC, Pathways Of The Pulp, Sixth Edition, 1994, pg 692-693. When teeth are extracted because of persisting pain after endodontic therapy the cause is usually treatment failure, but occasionally it may be the result of crown or root fractures
122. Paste filling materials may prove useful in filling root canals of:
routine endodontic cases
maxillary third molars
immature teeth with open apices
all of the above
Cohen, S, Burns, RC, Pathways Of The Pulp, Sixth Edition, 1994, pg 221, 265, Paste-type filling materials include zinc oxide-eugenol cements with various additives, zinc oxide, and synthetic resins (cavit), epoxy resins (AH-226), acrylic, polyethylene, and polyvinyl resins (Diaket), polycarboxylate cements, and silicone rubber. Sometimes a solvent-altered gutta-percha paste has been used ad the sole canal-filing material.
Pg. 265 One instance in which pastes, despite their low density and their tendency to be easily forced out beyond the apical foramen, may prove useful is in the filling root canals of primary teeth.
Pg. 662 Many techniques have been advocated to manage the pulpless permanent tooth with a incompletely developed apex. The canals are cleaned and filled with a temporary past to stimulate the formation of calcified tissue at the apex. The temporary paste is later removed after radiographic evidence of apical closure has be obtained and a permanent filling of gutta-percha is placed in the canal. The term apexification is used to describe this procedure. The use of calcium hydroxide for this was first reported by Kaiser in 1964.
123. In cases of vital extirpation, endodontically treated teeth are much more comfortable to the patient if the root canal is filled
to the radiographic apex
1 mm short of the radiographic apex
2 mm short of the radiographic apex
to the anatomic apex
just beyond the apex
Cohen, S, Burns, RC, Pathways Of The Pulp, Sixth Edition, 1994, pg 268, Gross excess of filling materials beyond the apical foramen is an unnecessary invasion of the attachment apparatus, resulting needless postfilling pain and discomfort. The most desirable vertical extent of the root canal filling is a homogeneously dense filling extending 0.5 to 1 mm short of the radiographic
124. The principle process by which debridement occurs during ultrasonic instrumentation is:
a. Acoustical streaming
e. By creating bubbles
The mechanism by which ultrasonics accomplish their cleaning were described initially as being implosion or cavitation. This was defined as the creation of a vacuum in the center of the unwanted cell that collapsed the cell inwardly. Further investigations have led to still another theory - acoustic streaming. This is defined as creating rapid movement of particles of fluid around a vibrating object, such as an endodontic file, with a vortex like motion. In endodontics this caused the liquid irrigant to run up and down very close to the file in an irregular eddy-like motion, most rapidly at the tip.
Implosion and cavitation then are essentially the same thing. Effervescence and bubbles are the same thing so the answer is acoustical streaming. Reference - Endodontic Therapy
125. In the management of odontogenic infections, Flagyl:
1. Is bactericidal against strict anaerobes in chronic infections
2. Is bactericidal against facultative anaerobes in cellulitis stand of infections
3. Has the side effect of gastrointestinal upset which can be exacerbated with alcohol consumption.
4. Should be used in combination with PCN or cephalosporin in serious infections.
5. Is most effective when used as a solitary antibiotic agent in managing chronic infections.
Flagyl or metronidozole is active only against obligate anaerobic bacteria.
Flagyl does have an antibuse like quality.
Since flagyl is effective against only obligate anaerobes and most infections are mixed it should be combined with another drug which is most commonly PCN or clindomycin. Reference. Pharmacology and Therapeutics for Dentistry by Neidle and Yagiela.
Another unrelated tidbit - Flagyl is the drug used to treat psudomembranous colitis caused by Clostridium difficile.
126. Which of the following require antibiotic prophylaxis?
1. organic heart murmur
2. cardiac pacemakers
3. isolated secundum atrial septal detect
4. previous history of endocarditis
5. most artificial joint patients
e. all of the above
ENDOCARDITIS PROPHYLALXIS RECOMMENDED
-Prosthetic heart valves, including bioprosthetic and homograft valves
-Previous bacterial endocarditis
-Complex cyanotic congenital heart disease (e.g., single ventricle states, transposition of the great
tetralogy of Fallot)
-Surgically constructed systemic pulmonary shuts or conduits
-Most other congenital cardiac malformations (other than above or below)
-Acquired valvar dysfunction (e.g., rheumatic heart disease)
-Mitral valve prolapse with valvar regurgitation and or thickened leaflets
ENDOCARDITIS PROPHYLAXIS NOT RECOMMENDED
-Isolated secundum atrial septal defects
-Surgical repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus (without
residua beyond 6 months)
-Previous coronary artery biopsy graft surgery
-Mitral valve prolapse without valvar regurgitation
-Physiologic, functional, or innocent heart murmurs
-Previous Kawasaki disease without valvar dysfunction
-Previous rheumatic fever without valvar dysfunction
-Cardiac pacemakers (intravascular and epicardial) and implanted defibrillators
Ref: Commander M. A. Huber, DC, USN, REVIEW OF ANTIMICROBIAL PROPHYLAXIS, Clinical Update - July 1997,
127. A patient has general sensation of the anterior 2/3 of the tongue, but due to lack of taste perception, does not enjoy his meals. Which nerve is involved?
d. Chorda Tympani
Note: The Chorda Tympani is a branch off of the facial nerve.
128. A patient has sustained bilateral fractures in the region of the mandibular condylar necks. There are no other injuries. Clinical signs will include:
a. inability to protrude the mandible
b. inability to contact the molar teeth
c. anterior closed bite
d. gross unilateral deviation of the mandible on excursion attempts
e. mental nerve anesthesia
The lateral pterygoid muscles attached to the condyles are not able to properly perform the function of mandibular protrusion/ excursion. Since the condyles are fractured bilaterally the there would not be a
deviation to one side over the other. When this type of fracture occurs there is a collapse of the posterior segment allowing the posterior teeth to come into contact but also creating an anterior open bite in the process. There would not be any mental nerve anesthesia because as noted there have been no other injuries and the mandibular/ mental nerve enters the mandible at a level inferior to the condylar necks.
Ref: Kruger, Oral and Maxillofacial Surgery, 6th edition, p378-385.
129. The two areas most vulnerable to fracture in the mandible (incidence sites) are:
a. Mental foramen and coronoid process
b. Symphysis and angle of mandible
c. Angle and condyle area
d. Molar region and cuspid area
e. Across ascending ramus and molar region
Answer C. Angle and condyle area
The incidence of fractures is as follows :
Condyle = 29.1%
Angle = 24.5%
Symphysis = 22%
Body = 16%
Ramus = 1.7%
Coronoid process = 1.3%
(Contemporary Oral and Maxillofacial Surgery Peterson, et.al. p. 595)
130. Treatment of fractures of the condyle requires:
a. Immobilization of the mandible for 6-8 weeks
b. Open reduction and pinning
c. Condylectomy later, if the fracture is intracapsular
d. Early mobilization of the mandible to avoid TMJ dysfunction or ankylosis
e. Early open procedures when the condyle is displaced into the infratemporal fossa.
Answer D. Early mobilization of the mandible to avoid TMJ dysfunction or ankylosis
Intermaxillary fixation (IMF) is used for a maximum of 2-3 weeks in adults and 10-14 days in children, followed by a period of aggressive functional rehabilitation to avoid TMJ dysfunction or ankylosis.
Contemporary Oral and Maxillofacial Surgery. Peterson, et.al. 1993 p. 602
Because of trauma to the joint structures, an ever-present danger exists of ankylosis of the condyle to the glenoid fossa. Early manipulation during healing will create movement in the joint rather than in the fracture if it is done carefully, and primary healing of the fractures parts will occur with no ankylosis in the joint. Textbook of Oral and Maxillofacial Surgery. Kruger, 6th edition, 1984.
Closed reduction - treatment of the fracture using only IMF , does not involve direct opening, exposure, and manipulation of the fractured area.
Open reduction - direct exosure and reduction of the fracture through a surgical incision
131. What is the most important factor involved in controlling post surgical bleeding?
A. Requesting PT and PTT prior to surgery
b. Administer local anesthetic with epinephrine
c. Good visualization of the hemorrhaging area
d. Expert surgical closure technique
e. Applying pressure tooth area of hemorrhage
Answer C good visualization of the hemorrhaging area
Even after primary hemostasis has been achieved, patients occasionally return to the dentist with bleeding from the extraction site, so-called secondary bleeding. ( I am interpreting post surgical bleeding with secondary bleeding) The surgeon must have an orderly, planned regimen to control this bleeding. The patient should be positioned in the dental chair, and all blood, saliva, and fluids should be suctioned from the mouth. The surgeon should visualize the bleeding site carefully with good light to determine the precise source of bleeding. If it clearly seen to be a generalized oozing,, the bleeding site is covered with a folded, damp 2 - by 2 inch sponge held in place with firm pressure for at least 5 minutes. This measure is sufficient to control most bleeding. The reason for bleeding is usually some secondary trauma that is potentiated by the patient’s continuing to suck on the area or spit blood from the mouth instead of continuing to apply pressure with a gauze.
If 5 minutes of this treatment does not control the bleeding, the surgeon must administer a local anesthetic so that the socket can be treated more aggessively. Block techniques are to be encouraged instead of local infiltration techniques. Infiltration with solutions containing epinephrine cause vasoconstriction and may control the bleeding temporarily. However, when the effects of the epinephrine dissipate, the may be rebound hemorrhage with recurrent bleeding.
Once local anesthesia has been achieved, the surgeon should gently curette out the tooth extraction socket and suction all areas of old blood clot. The same measures described for control of primary bleeding should be employed. The surgeon should decide if a hemostatic agent should be inserted into the bony socket. The use of an absorbable gelatin sponge with topical thrombin held in position with a figure eight stitch and reinforced with application of firm pressure from a small, damp gauze is standard for local control of secondary bleeding.
If hemostasis is not achieved by any of the local measures, the surgeon should consider performing additional laboratory screening tests to determine if the patient has a hemostatic defect.
Contemporary Oral and Maxillofacial Surgery. Peterson, 1993, p. 282-286.
Which of the following techniques should be followed when planning a mucoperiosteal flap?
The flap should be as small as possible to promote better healing
The flap should be wider than the bone cavity
The base should be wider than free margins.
The operative site should be adequately exposed.
Best answer is e.
Basically the indication for surgical flaps is inability to remove the structure or tissue without traumatizing the surrounding tissues. If a closed procedure fails , adequate visualization and access are obtained by means of an open procedure. Operations requiring a surgical flap are called open procedures. The operative site should be adequately exposed.
Principles. Healing should take place without complication if basic surgical principles are followed. The incision should be designed so that blood supply of the flap is adequate. If the free end of the flap is wide and the base containing the blood supply is narrow, nutrition to the flap may be inadequate. The flap should contain all the structures overlying bone, including mucosa, submucosa, and periosteum, with special care given to include the periosteum in the flap. The flap should be sufficiently large that adequate vision and space for removal of bone are present without damaging the soft tissues edges. The incision should always be made over bone that will not be removed, so that the sutured incisions are supported by bone. Incision made in tissues that harbor uncontrolled infection may cause rapid spread of infection.
REF: Kruger, G.O., Oral and Maxillofacial Surgery Sixth edition 1984 p. 69.
Which of the following conditions is a contraindication to nitrous oxide analgesia?
Chronic obstructive pulmonary disease
Best answer is c.
COPD represents a relative contraindication to inhalation sedation, not because of the nitrous oxide, but because the gas mixture is enriched with oxygen. Patients with COPD have lost their ability to respond to elevated carbon dioxide levels in the blood as their primary stimulus to breath. Instead they respond to decreased blood oxygen content. Theoretically these patients should experience apnea when given nitrous oxide/ oxygen sedation. This does not occur in the conscious individual since voluntary control over breathing is possible.
Nitrous oxide is not metabolized by the liver or excreted through the kidneys, therefore hepatic and renal disease do not contraindicate its use.
Nitrous oxide/oxygen sedation is actually the preferred method of sedation for patients with a history of cerebral vascular accident because of the increased oxygen levels that are provided.
In our litigious society , the performance of any elective dental treatment or administration of any pharmacological agent to a pregnant patient may be legally contraindicated. However, there is no medical reason against using nitrous oxide/oxygen sedation after the first trimester.
Ref: Malamed, emergency in the Dental Office pp. 175-176.
Allen, p 267.
A patient is taking coumadin: Which blood study do you use to determine his status for surgery?
WBC and differential
e. both b and c
Best answer is c.
White Blood Cell count (4,500-11,000cells/mm3) normal range.
The white blood cell count expresses the number of WBCs per cubic millimeter of whole blood. WBCs (leukocytes) are classified as either granulocytes (neutrophils, eosinohils, basophils) or non-granulocutyes (lymphocytes, monocytes).
Increased WBCs- extreme temperature, pregnancy, infectious disease (the most common cause for increase), Leukemia.
Decreased WBCs- pernicious anemia (vitamin B12 deficiency), Aplastic anemia (no cell’s produced in the bone marrow), Bone marrow depression secondary to chemo/radiotherapy, Malignant neutropenia or myeloproliferative syndrome (chronic leukemia, polycythemia, thrombocytopenia).
Differential White Cell Count
To identify the various types of leukocytes and their relative amounts in sample, a differential count can be performed. Many labs now use automation to perform this test. The white cells are screened on the basis of 3 sizes: small (normal lymphocytes), middle (monocytes, eosinophils, large lymphocytes variants), and large (neutrophils (stabs & bands)). If one of these cell population fall outside the reference range, the sample is placed on a slide and microscopic differential is performed by a lab technician.
Platelet Count: This test provides a quantitative evaluation of platelet number. Normal counts range from 140,000 to 400,000 platelets/mm3. In most cases, clinical bleeding problems are associated with platelet counts of less than 50,000 platelets/mm3. The average life span of a platelet is 9 to 12 days.
Bleeding Time (BT): This test an assessment of the adequacy of platelet count and function. It is a measure of how long it takes a standardized skin incision to stop bleeding. Depending on the test used, a normal bleeding time ranges from 1 to 6 minutes. Elevated bleeding times are seen with platelet abnormalities.
Prothrombin Time (PT): This test measures the effectiveness of extrinsic coagulation pathway. It is performed by measuring the time it takes to form a clot when calcium and a tissue factor are added to the patient’s plasma. A normal PT indicates normal levels of Factor VII and those factors common to both the intrinsic and extrinsic pathways (V,X, prthrombin and fibrinogen) A normal PT typically ranges from 10 to 15 seconds, and is usually compared to a daily control value. A prolonged PT can be associated with abnormal postoperative coagulation and bleeding. Prolongation of less than one half times the control value is usually associated with mild bleeding disorders, while further prolongation indicates a more severe bleeding disorder. The PT is often used to monitor oral anticoagulant therapy i.e. coumadin.
Coumarin is a vitamin K antagonist. Vitamin K is necessary for final activation of factors II(prothrombin), VII, IX, and X.
International Normalized Ratio (INR) For patients on chronic oral anticoagulants, i.e. coumarin, the INR is now gaining acceptance for the reporting of prothombin time ratio
(PTR), that is the patient’s PT compared to the lab’s PT. The INR allows comparison from one hospital to another, especially in the studies of the ideal therapeutic range of PTR. By using an international sensitivity index (ISI) which is determined for each batch of reagent and is specific to the lab’s particular equipment, the calculation of INR = (patient PT/normal PT) ISI. For most conditions that require ongoing anticoagulation therapy, the American Heart Association has recommended INR levels between 2.0 and 3.0.
Partial Thromboplastin Time (PTT): This test measure the effectiveness of the intrinsic coagulation pathway. It test all factors except Factor VII. The test is performed by measuring the time it takes to form a clot after addition of kaolin, a surface acting cephalin (a substitute for platelet factor), to the patient’s plasma. A normal value typically ranges from 25 to 35 seconds, and is usually compared with a daily control.
PTT values 5 to 10 seconds above the upper limit of normal may be associated with mild bleeding abnormalities, while higher values are associated with significant bleeding risks. PTT is often used to monitor heparin therapy.
Thrombin Time (TT): This test measures the time it takes thrombin to convert fibrinogen to fibrin, which constitutes the essential components of a blood clot. The TT is a fairly good test to identify fibrinolysis disorders. Normal TT values range from 9 to 13 seconds and are compared with a laboratory control. Results in excess of 16 to 18 seconds are considered prolonged.
REF: Oral Diagnosis Class 1996 LECTURE HAND OUTS Laboratory Studies Hematolgic Screening and Evaluation of Hemostasis.
135. The most effective local anesthetic employed in an inflamed area would be
a. Bupivicaine because of low lipid solubility
b. Lidocaine because of high dissociation constant, pKa
c. Mepivicaine because of low dissociation constant, pKa
d. Mepivicaine because of high protein binding
e. Bupivicaine because of high potency
“Those anesthetic agents that have a high pKa will have few molecules present as the free base (lipid-soluble form) at normal tissue pH (7.3 to 7.4). Therefore the anesthetic quality will be poor since an insufficient number of free-base molecules are present.
Conversely those anesthetic agents with a very low pKa provide a large number of free-base molecules to diffuse through the neural sheath. However, this agent, too, would be relatively ineffective since very few base molecules would dissociate to the cationic form, the one necessary for attachment to the specific receptor site.....
In contrast to alkaline conditions, a low tissue pH, as found in infected areas (pus has a pH of 5.5 to 5.6), may interfere with the development of adequate anesthesia by preventing deprotonization and liberation of the free base.
The potential action of all local anesthetics depends on the ability of the anesthetic salt to liberate the free alkaloid base....”
pKa’s of local anesthtics:
“a” is incorrect as bupivicaine actually has a HIGH lipid solubility
“b” is incorrect as lidocaine has an average--to low dissociation constant
“d” is incorrect as mepivicaine has average protein binding when compared to the other anesthetic agents
“ e” is incorrect as high potency has to do with protein binding and not pKa or pH.
Monheim’s Local Anesthesia and Pain Control in Dental Practice, Bennet C. Richard, Seventh Edition, 1984, pp.125-159
(Remember that... IOCAINE POWDER .....comes from Australia and is odorless, colorless, and tasteless!!)
136. Which of the following is NOT correct regarding the placement of dental implants?
a. It is desirable for the implant to reach the inferior cortex of the mandible for stabilization
b. With low mandibular height, the inferior cortical bone may be intentionally perforated
c. Sites of failed implants can be revised for another fixture after one year
d. Osseointegration occurs more rapidly in the maxilla than the mandible due to better blood
e. Recommended waiting at least 4 months in the mandible and 6 months in the maxilla prior to
beginning stage two
“a” is a correct statement “ The apical portion of the implant should be within the cortical bone of the inferior border.” (P. 399)
“b” is a correct statement: “In the severely atrophic mandible, the shortest implant may be longer than the available bone. Implants may be placed purposefully perforating the inferior cortex.” (P.403)
“c” is a correct statement “If mobility is detected, the implant should be removed at that time. The failed site is allowed to heal (at least 12 months) and another implant can be placed at a later time.” (P. 374)
“d” is an incorrect statement. “...since the maxilla is primarily cancellous bone, osteointegration requires a longer healing period.” (P. 373)
“e” is a correct statement as per the table provided on page 392 ( table 15.2...minimum integration times)
Contemporary Oral and Maxillofacial Surgery, Petterson, Ellis, Hupp, Tucker, second edition. 1993.
137. When applying forceps to extract maxillary posterior teeth, the initial direction of the force applied to the tooth is
As per illustration on page 175 of Contemporary Oral and Maxillofacial Surgery, Petterson , et al, 1993, the initial forces used to extract a maxillary posterior tooth is apical, then followed by palatal, and buccal, then finally occlusal to remove it. Cannot use rotational forces because of the multiple and divergent root systems. Cannot usually move teeth in the mesial-distal direction because of surrounding teeth, also the forceps are not designed to provide this motion adequately.
Normally, the clinician would NOT biopsy in which of the following situations?
suspicious recent biopsy site, with negative findings
recent trauma-induced lesion
1 month old leukoplakia lesion
1 month old erythoplakia lesion
suspected vascular lesion
1, 2, 5
2, 3, 5
3, 4, 5
1, 3, 4
Ref. OS classnotes. Conraindications to Biopsy:
1. Normal anatomic structure
2. Developmental variant
3. Trauma-induced lesion
4. Pulsatile lesion
5. Clinical experience
Indications for Biopsy:
1. Confirm diagnosis
2. Fails to heal
3. Suspected neoplasm
4. Verify metabolic disorders
5. Stage/ Prognosis
6. Hyperkeratotic lesion
139. The maximum dosage of epinephrine _____ / levonordefrin (neo-cobefrin) _____ that should be administered to a normal healthy adult during any one dental procedure is
0.018 mg / 0.8 mg
0.2 mg / 0.5 mg
1.8 mg / 0.2 mg
0.2 mg / 1.8 mg
0.04 mg / 0.4 mg
The New York Heart Association recommends that for any one session no more than 0.2 mg (11.1 carpules @ 1:100,000) epinephrine and 0.5 mg levonordefrin be given to a healthy adult. Patients with organic heart disease should not receive more than 0.04 mg (2.2 carpules @ 1:100,00) epinephrine and 0.2 mg levonordefrin.
Ref. Clinical Pharmacology in Dental Practice. Holroyd, Wynn and Requa-Clark. Mosby, 1988.
140. If a fever develops 48 to 72 hours after tooth extraction, the problem may result from
1, 2, 4
1, 2, 5
1, 3, 5
2, 4, 5
e. any of the above
Beyond the first 48 hours, persistent postoperative fever may be due to bacterial infections of the surgical wound. Adverse drug reactions should be considered in the differential diagnosis of both early and late postoperative fever, even when there has been no new agent introduced. Altered drug therapy or elimination of medications may be necessary after infectious etiologies have been ruled out. Postoperative infection is usually due to debris which is left under the mucoperiosteal flap and may progress to an acute subperiosteal cellulitis of which one symptom is elevated temperature along with swelling, pain and trismus.
The onset of endocarditis is often insidious and the patient is often unable to pinpoint when the disease first started. The process of colonization of the platelet-fibrin thrombus on the endocardium usually takes 1-4 weeks. Symptoms include weakness, weight loss, fatigue, fever, chills, night sweats, anorexia and arthralgia.
Ref. Contemporary Oral and Maxillofacial Surgery, Second Edition, 1993. Peterson, , Hupp and Tucker.
Impacted Teeth, 1993. Alling, CC, Helfrick, JF, Alling, RD
Textbook of Oral and Maxillofacial Surgery, Sixth Edition, 1984. Kruger, GO.
Fever after the first 24 hours: Anesthesia, transfusion reactions, IV complications, hematoma, lung infection, urinary tract infection, wound infection, fat emboli.
Ref. Oral and Maxillofacial Surgery, Volume One, 1980. Laskin, D.
141. A small accidental opening into the maxillary sinus results from the removal of a maxillary first molar, but the sinus membrane shows no perforation. The preferred initial treatment is to
a. elevate a buccal sliding flap and cover the entire
b. rotate a pedicle flap from the palate over the socket and
suture tightly with nonresorbable sutures.
c. have the patient perform the Valsalva maneuver until
bubbles can be seen in the socket.
d. pack the socket with antibiotic-saturated iodoform gauze.
e. perform routine postoperative care to assure the formation
and organization of a blood clot.
An opening may be made into the maxillary sinus when teeth are removed and occasionally as a result of trauma. This happens particularly when a maxillary molar with widely divergent roots that is adjacent to edentulous spaces requires extraction. In this instance the sinus is likely to become pneumatized into the edentulous alveolar process.surrounding the tooth, weakening the entire alveolus and bringing the tooth apices into a closer relationship with the sinus cavity. Other causes of perforation into the sinus include destruction of a portion of the sinus floor by periapical lesions, perforation of the floor and sinus membrane with injudicious use of instruments, forcing a root or tooth into the sinus during attempted removal, and reim0val of large cystic lesions that encroach on the sinus cavity.
The treatment of oroantral communications is accomplished either immediately, when the opening is created, or later as in the instance of a long-standing fistula or failure of an attempted primary closure.
The best treatment of a potential sinus exposure is avoiding the problem through careful observation and treatment planning. Evaluation of high-quality radiographs before surgery begins usually reveals the presence or abscence of an excessively pneumatized sinus or widely divergent or dilacerated roots, which have the potential of having a communication with the sinus or causing fractures in the bony floor of the antrum during removal. If this observation is made, surgery may be altered to section the tooth and remove it.
When exposure and perforation of the antrum result, the least invasive therapy is indicated initially. If the opening to the sinus is small and the sinus is disease free, efforts should be made to establish a blood clot in the extraction site and preserve it in place. Additional soft tissue flap elevation is not required. Sutures are placed to reposition the soft tissues, and a gauze pack is placed over the surgical site for 1 to 2 hours. The patient is instructed to use nasal precautions for 10 to 14 days. These include avoiding nose blowing, opening the mouth while sneezing, not sucking on a straw or cigarettes, and avoiding any other situation that may produce pressure changes between the nasal passages and oral cavity. The patient is placed on (AAA): an antibiotic, usually penicillin or Augmentin; an antihistamine (Actifed); and a systemic decongestant (Afrin) for 7 to 10 days to prevent infection, to shrink mucous membranes, and to lessen nasal and sinus secretions. The patient is seen postoperatively at 48 to 72-hour intervals and is instructed to return if an oroantral communication becomes evident by leakage of air into the mouth or fluid into the nose or if symptoms of maxillary sinusitis appear. The majority of patients treated in this manner heal uneventfully if there was no evidence of preexisting sinus disease.
Contemporary Oral and Maxillofacial Surgery Petersen et. al. 1988 p. 445
142. The most definite clinical sign indicating extension of an odontogenic infection into the masticator space is
a. swelling of the submandibular area
c. difficulty swallowing
e. elevated body temperature above 101 degrees F
Secondary fascial spaces
The group of spaces when taken as a group, the masseteric, pterygomandibular, and temporal spaces are known as the masticator space, because they are bounded by the muscles and fascia of mastication. These spaces communicate freely with one another, so when one becomes involved the others may also. The term masticator space does have some general clinical usefulness, but it lacks specificity and is therefore less useful than specific space designations.
The primary spaces are immediately adjacent to the tooth-bearing portions of the maxilla and mandible. If proper treatment is not received for infections of the primary spaces, the infections may extend posteriorly to involve the secondary fascial spaces. When this occurs, the infections frequently become more severe, causing greater complications and greater morbidity, and more difficult to treat. Because these spaces are surrounded by connective tissue fascia, which has a poor blood supply, infections involving these spaces are difficult to treat without surgical intervention to drain the purulent exudate.
The masseteric space exists between the lateral aspect of the mandible and the medial boundary of the masseter muscle . It is involved by infection most commonly as the result of spread from the buccal space or from soft tissue infection around the mandibular third molar. When the masseteric space is involved, the area overlying the angle of the jaw and ramus becomes swollen. Because of the involvement of the masseter muscle, the patient will also have moderate to severe trismus caused by inflammation of the masseter muscle.
The pterygomandibular space lies medial to the mandible and lateral to the roedial pterygoid muscle. This is the space into which local anesthetic solution is injected when an inferior alveolar nerve block is performed. Infections of this space spread primarily from the sublingual and submandibular spaces. When the pterygomandibular space alone is involved, there is little or no facial swelling, but the patient almost always has significant trismus. Therefore trismus without swelling is a valuable diagnostic clue for pterygomandibular space infection. The most common occurrence of this clinical picture is caused by needle tract infection from a manbidular block.
The temporal space is posterior and superior to the masseteric and pterygomandibular spaces . It is divided into two portions by the temporalis muscle--a superficial portion that extends to the temporal fascia and a deep portion that is continuous with the infratemporal space. The superficial and deep temporal spaces are secondarily involved rarely and usually only in severe infections. When these spaces are involved, the swelling that occurs is evident in the temporal area, superior to the zygomatic arch and posterior to the lateral orbital rim.
Contemporary Oral and Maxillofacial Surgery Petersen et. al. 1988 p. 415
143. For the treatment of a patient who has a high risk of contracting bacterial endocarditis, prophylaxis is recommended for which type of anesthetic injection?
a. Inferior alveolar block
b. Second division block
c. Periodontal ligament injection
d. Buccal infiltration
All of the above
See JADA July 1997 p.1005, Incidence Stratification of Bacteremic Dental Procedures Intraligamentary local anesthetics injections occur at a higher incidence.
144. The safest drugs to administer during pregnancy are:
ASA, phenacetin, valium, lidocaine
acetaminophen, codeine, erythromycin, lidocaine
ASA, tetracycline, codeine, mepivicaine
acetaminophen, codeine, strepomycin, mepivicaine
ibuprophen, codeine, penicillin, lidocaine
Peterson, LJ, Ellis, E III, Hupp, JR, Tucker, MR, Contemporary Oral And Maxillofacial Surgery 2nd Edition, Mosby-Year Book, Inc., pg 20-21.
“For purposes of oral surgery the following drugs are believed least likely to harm a fetus when used in moderate amounts: Lidocaine, bupivacaine, acetaminophen, codeine, penicillin, and erythromycin. Although aspirin is otherwise safe to use, it should not be given late the third trimester because of its anticoagulant property. All sedative drugs are best avoided in pregnant patients. Nitrous oxide would not be used during the first trimester but if necessary can be used in the second and third trimesters as long as it is delivered with at least 50% oxygen.”
Little, JW, Falace, DA, Miller, CS, Rhodus, NL, Dental Management Of The Medically Compromised Patient., 5th Edition Mosby-Year Book, Inc., Pg. 438.
Food and Drug Administration categorization of prescription drugs for pregnant patients.
Controlled studies in humans have failed to demostrate a risk to the fetus, and the possibility of fetal harm appears remote.
Animal studies have not indicated fetal risk, and there are no human studies; or animal studies have shown a risk, but controlled human studies have not.
Animal studies have shown a risk, but there are no controlled human studies; or no studies are available in humans or animals
Positive evidence of human fetal risk exists, but in certain situations the drug may be used despite its risks.
Evidence of fetal abnormalities and/or fetal risk exists based on human experience, and the risk outweighs any possible benefit of use during pregnancy.
145. Which of the following are TRUE of a cavernous sinus thrombosis?
1. spreads via facial veins
2. slow, gradual onset, with increased pressure in the eye
3. spreads via facial or angular artery
4. inability to gaze laterally
5. impaired vision, proptosis, and ptosis
6. paralysis of lateral rectus muscle
7. increased lacrimation
8. first cranial nerves to be affected are the oculomotor and trochlear nerves
Topzian, RG, Goldberg, MH, Oral And Maxillofacial Infections, 2nd Edition, W.B.Saunders Co., 1987; 174-175.
Cavernous Sinus Thrombosis...valveless anterior and posterior facial veins...patient presenting with proptosis, fever, obtunded state of consciousness, ophthalmoplegia, or paresis of the oculomotor, trochlear, and abducens nerves, following maxillary infections and exodontia.
Bates, B, Bickley, LS, Hoekelman, RA, A Guide To Physical Examination And History Taking. J.B.Lippincott Co., 6th edition; 1995;494..
pupillary constriction, opening the eye, and most extraocular movements.
Downward, inward movement of the eye.
Lateral deviation of the eye
146. With all external parameters kept constant, list the following surgical techniques in order from most rapid healing to slowest healing.
Liboon, J, Funkhouser, W, Terris DJ, A Comparison Of Mucosal Incisions Made By Scalpel, CO2 Laser, Electrocautery, And Constant-Voltage Electocautery., Otolaryngol Head Neck Surg 1997 Mar; 116(3):379-385.
Histologic damage was least with a scalpel. The extent of epithelial damage lateral to the woulnd edge and the extent of collagen denaturation were the lowest the scalpel followed by constant-voltage electrosurgery. ...constant-voltage electrosurgery wounds had significantly more granulation tissue in later weeks, suggesting wound healing may be delayed.
147. Immunohistochemical studies of a biopsy should be considered when a clinician suspects
1. Lichen planus
2. Lupus erythematosis
3. Bullous pemphigoid
All can be identified by immunofluorescence. Reference: Class notes Oral Pathology 16 Mar 97
148. What is the best radiograph to view the subcondyler area?
1. Water’s view Best for the maxillary sinus
2. Submental vertex (Jug handle) Best for the zygomatic arches
3. Modified Towne’s Best view of the condyler neck
4. Lateral oblique Best view of the body, ramus and coronoid process
5. A-P view of the skull Best for frontal sinus and superior and inferior orbital ridges
Reference: Oral and Maxillofacial surgery
149. Dental treatment is best performed on a hemodialysis patient
a. Immediately before hemodialysis
b. Immediately after hemodialysis
c. 1 day after hemodialysis
d. 1 day before hemodialysis
e. 2 or 3 days after hemodialysis
The dialysis patient should be treated on the day after their dialysis. Dialysis is usually done every 2-3 days. The day after the patients blood is clean and they feel the best. As the time for another session approaches the patient fells worse. The sessions take 3-5 hours and leave the patient feeling somewhat drained. (No pun intended) The dialysis destroys the platelets and alters their aggregation so the patients bleeding time should be monitored prior the surgery. Dosages of drugs that are eliminated in the kidneys may need to be modified. Aspirin, Tylenol, motrin, PCN, valium, TCN. Reference: Little and Falace
150. A fluctuant sublingual space infection persists following removal of an infected tooth. Follow-up treatment should include
a. Antibiotics and intra oral incision and drainage if the swelling bulges downward.
b. Antibiotics and intra oral incision and drainage if the swelling bulges upward
c. Antibiotics and extra oral incision and drainage if the swelling bulges upward
d. Antibiotics without I&D
e. Antibiotics, curettage of the extraction site and antimicrobial rinses twice a day for 10 days.
A sublingual space infection usually results form infection of a posterior tooth whose apex is above the mylohyoid muscle, the premolars or first molar. It will bulge upward under the tongue not downward. The submandibular infection bulges downward. The indications for an I&D are either cellulitis or a fluctuant abscess. Classically you waited for the swelling to become fluctuant before draining it. Today the thought is to drain early whether there is pus present or not. Besides removing necrotic gunk it decompresses the tissues, restores blood flow and changes the flora with the introduction of oxygen to the area. Reference Dr. Barrett and oral and Maxillofacial surgery.
ORAL PATHOLOGY / ORAL MEDICINE QUESTIONS
151. An 8-year-old male presents with an expansile, multilocular radiolucency involving the posterior mandible and associated with impacted #30. The lesion is biopsied and the pathologist's report describes multinucleated giant cell and dilated vascular spaces.The most likely diagnosis would be:
aneurysmal bone cyst
Oral Pathology, Lee, 1985
Descriptions: Ameloblastic Fibroma- usually in the mandible, especially in the premolar/molar area. Slow growing, and causes painless expansion of the jaw. Radiographically presents as well-defined area that may be either uniloclear or multiloclear. Odontogenic Keratocyst- (primordial cysts) 70-80 in the mandible and about 50% of those at the angle. More common in males. Peak incidence in the second and third decades. Expansile and teeth may be displaced. Some cysts appear to surround the crown of an unerupted tooth. Histological characteristic is the structure of the epithelial lining. Aneurysmal Bone Cyst - Blood containing intrabony lesions. Rare in the jaws but the mandible is affected twice as often as the maxilla. The majority of the patients are under 20 years of age. Typically painless swelling. May be migration of the teeth. Uniloclear or multiloclear. Macroscopically the lesion has a thin shell of subperiosteal new bone and soft tissue containing blood filled spaces. Multinucleated giant cells may be numerous. Dentigerous Cyst- Surrounds the crown and is attached to the neck of an unerupted tooth. Twice as common in men. Most seen in the second and fourth decade of life. Uniloclear well defined area.
Ameloblastoma- Slow growing painless expansion usually in patients between 20 and 50. Most commonly multiloclear cystic radiolucency with a distinct radiopaque margin. May contain an unerupted tooth.
152. Which of the following statements concerning the process of differentiating oral ulcerations is true?
a. The ulcers of recurrent aphthous stomatitis arise most frequently in keratinized mucosa that is tightly bound to the periosteum.
b. The ulcers of recurrent intraoral herpes simplex are usually not surrounded by an erythematous halo.
c. The ulcers of recurrent intraoral herpes simplex commonly occur on freely movable, non-keratinized mucosa.
d. Early lesions of aphthous stomatitis show ballooning degeneration and intranuclear inclusions.
e. The ulcers of recurrent intraoral herpes simplex usually occur singularly.
(Oral Path Class notes)
Recurrent ulcerative mucosal lesions which heal with periodicity (time period can be variable from one patient to another) , almost always are due to recurrent aphthae or herpes. Recurrent herpetic and aphthous lesions can be differentiated on the anatomic location of the lesions. Recurrent herpetic lesions occur on keratinized mucosal surfaces (hard palate, attached gingiva, lips, dorsum of the tongue and epidermis). Recurrent herpetic lesions also usually recur in the same anatomic location innervated by the involved sensory nerve. Aphthous ulcers occur on non keratinized mucosal surfaces with a random distribution.
Recurrent herpes is usually first noted as a cluster of individual small vesicles either on the hard palate or the attached labial gingiva.
Clinical photographs of the intraoral herpes simplex lesions show the red halo effect.
153. A 58 year old female presents with a history of xerostomia, parotid gland swelling, dry eyes and rheumatoid arthritis. The most likely diagnosis would be:
a. Gardner's syndrome
b. Treacher-Collins syndrome
c. Marfan’s Syndrome
d. Sjogren's Syndrome
e. Mikulicz's Disease
Basic Pathology, Robbins, Angell, Kumar, third edition 1981
multiple supernumery teeth
delayed tooth eruption
Treacher- Collins Syndrome (A textbook of Oral Pathology, Shafer, 4th edition)
hypoplasia of facial bones
deficiency of eyelashes
malformation of the external ear
atypical hair growth
spider like fingers
high arched palate
defective heart valves
Sjogren's syndrome is a clinicopathologic entity secondary to an autoimmune disorder often involving rheumatoid arthritis and is then termed sicca syndrome. clinically the patient will present with dry eyes and dry mouth do to the destruction of the lacrimal and salivary glands by the immune system. Other immunologic disorders are also associated with the process and regarded as a secondary form although the overall pathogenesis is similar with the destruction of glands by infiltrating lymphocytes.
a. Bilateral swelling (BLEL)
d. Rheumatoid factors
e. 90% female 40 - 60 age group
Combined uveitis and parotitis due to sarcoidosis is known as Mikulicz Syndrome
154. With sickle cell anemia
a. Radiographs may show a lace-like trabecular pattern.
B. Nitrous oxide use in the treatment of patients contraindicated.
C. A crisis may be precipitated by odontogenic infections.
D. Prophylactic antibiotic coverage is indicated.
E. The oral mucosa appears hemorrrhagic and early eruption patterns are often seen.
Answer C. A crisis may be precipitated by odontogenic infections.
Dental management of the patient with sickle cell anemia must include good dental repair and prevention. An oral infection can precipitate a crisis.
Radiographs may appear as a “step-ladder” due to compensatory marrow expansion. The lamina dura may appear more dense and distinct. Patients often have delayed eruption of teeth and dental hypoplasia.
Patients with sickle cell anemia also may show pallor and evidence of jaundice in the oral tissues.
The use of nitrous oxide is not contraindicated. It is recommended to use 50% oxygen with a high flow rate. There is no indication for prophylactic antibiotic coverage.
Dental Management of the Medically Compromised Patient, Little and Fallace, 5th Edition , 1997.
155. Which of the following oral complications can occur following radiation therapy of 6000rads to the head and neck area:
4. rampant caries
5. Muscle trismus
d. 1 and 4 only
e. all of the above
The correct answer is e all of the above
Little and Fallace lists the complications associated with radiation therapy of 6000 rads to the head and neck in Table 25-19 on page 536 of the 5th edition of Dental Management of the Medically Compromised Patient. These include:
3. radiation caries
5. muscle trismus
During radiotherapy, the patient often will develop a mucositis. Breakdown of the oral mucosa begins about the second week and usually subsides a few weeks following the completion of treatment. The mucositis results in ulceration, pain, dysphagia , loss of tastes, and difficulty. If the major salivary glands have been irradiated, xerostomia will follow the initial onset of mucositis.
During radiation and postradiation therapy patients will be prone to secondary infection. Due to a decrease in actual salivary flow, as well as compositional alterations in saliva, there are several organisms that can easily opportunistically infect the oral cavity. In most patients, the ability to taste will return in 3 to 4 months following completion of radiotherapy. To minimize the effects of radiation on the muscles around the face and the muscles of mastication, a mouth block should be placed when the patient is receiving external beam irradiation; the patient should also be given a number of tongue blades to place in the mouth several times each day. These procedures will minimize muscle contracture and allow for more normal function and access to the oral cavity.
156. Which of the following types of hepatitis is most likely to be contacted through a blood transfusion.?
a. Hepatitis A
b. Hepatitis B
c. Hepatitis C
d. Hepatitis D
e. none of the above
The correct answer is Hepatitis C
Hepatitis A - almost exclusively transmitted by fecal contamination of food or water. Transmission is enhanced by poor personal hygiene, which places school-age youngsters, food handlers, daycare workers and travelers to developing countries at greater risk.
Hepatitis B - Transmission occurs through:
(1) percutaneous inoculation or transfusion of infective blood or blood products.
(2) indirect percutaneous introduction of infective serum or plasma, such as through minute skin abrasions
(3) absorption of infective serum or plasma, such as through mucosal surfaces of the mouth or eye.
(4) absorption of infective secretions, such as saliva or semen through mucosal surfaces
(5) transfer of infective serum or plasma via inanimate environmental surfaces or possibly vectors.
The risk of infection is directly proportional too exposure to blood.
Hepatitis C - Transmission is primarily by blood and blood and blood products. It is the major etiologic agent of posttransfusion hepatitis, accounting for 90% of the cases. Previously known as Non A Non B Hepatitis..High carrier rate as well as high rate of liver cancer in affected patients. Patients at risk include illicit drug users; healthcare worker exposed to blood, hemodialysis patients; and recipients of whole blood, blood cellular components, or plasma.
Hepatitis D - Occurs only as a coinfection with acute hepatitis B or as a superinfection in carriers of Hepatitis B and therefore is transmitted parenterally via infected blood or blood products. It is seen primarily in drug addicts and hemophiliacs.
Hepatitis E - (non-A non-B) resembles hepatitis A and is transmitted via fecal-oral contamination. The disease is endemic in India, Asia, Africa and Central America.
(Little and Fallace, Dental Management of the Medically Compromised Patient. 5th edition, 1997.
An ameloblastoma is most likely to develop from the epithelial lining of which of the following cyst?
Correct answer is b.
Periradicular cyst-Most common of all oral cysts. Practically all apical cysts originate from a pre-existing granuloma.
Epithelial cell rests of Malassez are stimulated to proliferate by pulpal inflammatory or necrotic irritants.
A true cyst; fluid filled epithelium lined.
The epithelium is surrounded by connective tissue that contains all the elements found in apical granuloma. The radicular cyst is an inflammatory lesion or a “cyst within a granuloma”.
The radicular cyst typically develops at the apex of a non-vital tooth, usually asymptomatic occasionally causing a painless bony expansion.
Radiographically it appears as a round or pear shaped radiolucency less than 1 cm in diameter, although some apical cysts have enlarged to 10 cm, causing displacement o the roots of adjacent teeth. the borders are well defined and may not be corticated.
Radiographically the apical cyst and periapical granuloma are indistinguishable.
Dentigerous Cyst- Most common pathological pericoronal radiolucency in the jaws.
They develop when fluid accumulates between the reduced epithelium and the crown of an unerupted tooth.
Commonly found with third molar (especially mandibular) or maxillary canine. They are most frequently seen in patients between 10-30 years of age, with a slight male predilection and higher prevalence in whites than blacks.
Typically a unilocular radiolucency associated with the crown of an unerupted tooth with well defined sclerotic borders.
Dentigerous cyst may displaced the involved tooth and in 50% of the cases can cause root resorption of adjacent erupted teeth.
Treatment of consists of careful enucleation of the cyst and removal of the unerupted tooth, recurrence is seldom noted.
The cyst lining may give rise to mucoepidermoid carcinoma, a mural amelobalstoma, and very rarely squamous cell carcinoma.
Residual periradicular cyst- term frequently applied to an apical periodontal cyst (radicular cyst) which remain after extraction of an infected tooth, or any cyst of the jaw that remains after surgery.
1. Usually a round radiolucency with well defined borders in edentulous area.
Lateral peridontal cyst- an uncommon developmental cyst; most often asymptomatic and detected coincidentally on routine radiographs.
Results from proliferation or rest cells from dental lamina. (Rests of Serres)
The lesion is associated with root surface of the tooth and is most commonly seen in the mandibular canine-premolar region. The less common maxillary examples are usually seen in the lateral incisor region.
Radiographically the cyst is a well circumscribed radiolucency lateral to the rots of vital teeth. Most are less than 1 cm in diameter. The radiographic feature are not diagnostic and the differential diagnosis should also include OKC and inflammatory radicular cysts.
They are usually found in patients older than 30 and there is a male predilection.
Occasionally these cyst may have a multilocular appearance and is termed a botryoid odontogenic cyst.
Treatment of choice is enucleation.
Odontogenic keratocyst- a distinctive form of developmental odontogenic cyst that arises from cell rests of dental lamina.
Usually occurs in the mandibular molar ramus region(60-80%), with a peak frequency of 2nd and 3rd decades and slight male prevalence.
Mandibular OKCs tend to enlarge and fill the entire ramus. Large OKCs may be associated with pain, swelling, and drainage. OKCs tend to grow in an anterior-posterior direction without causing obvious expansion of bone; while dentigerous cyst and radicular cysts of comparable size are usually associated with bony expansion.
3. Radiographically the lesion may be unilocular or multilocular, with margins that are sclerotic with scalloped outline. The lumen may be cloudy due to keratin present in the lumen. Although developing teeth may be displaced, the OKC usually doesn’t resorb adjacent teeth
Lesions recur frequently, although the orthokeratinizing variant does not recur as frequently as those producing parakeratin.
Treatment consist of enucleation and curettage. Due to the high recurrence rate, long term follow up is necessary. Only a few examples of malignant transformation have been reported
Basal cell nevus syndrome (Gorlin-Golz)is characterized by multiple OKCs, multiple basal cell caricinomas, palmar and planter pitting, and calcification of the falx cerebri. The multiple BCCs are often present on non exposed areas but are most commonly seen in mid-face region.
REF: Naval Dental School Oral & Maxillofacial Radiology 1997 Notes.
Lichen planus may exhibit which of the following manifestations?
White thread-like papules
Smooth red atrophic areas
all of the above
Correct answer is e.
Lichen planus is a relatively common condition affecting the skin and oral tissues in adult patients. The classic lesions of oral lichen planus are characterized by white linear and annular papules, primarily affecting the buccal mucosa. The lips, tongue and palate can also be involved. Other less common forms of the idsease have been identified. Terms such as Bullous, erosive, atrophic and hypertrophic have been used to describe the clinical appearance of the lesion. Because of the varied appearance of the disease , a diagnosis of lichen planus can only be confirmed with biopsy and histologic evaluation.
REF: Shafer, Hine, Levy. Oral Patholgy pp 809-12.
Which of the following conditions can result in enamel hypoplasia?
Advanced Paget’s disease
Correct answer is a.
During enamel formation, ameloblasts may be subjected to local and systemic influences that later affect teeth. Enamel of normal hardness, but lacking in quantity is known as enamel hypoplaia, while normal amounts of hypomineralization enamel is known as enamel hypocalcification. Childhood infections , such as congenital syphilis , and nutrition defects such as rickets, may lead to enamel hypoplasia and hypomineralization.
Patients with cleidocranial dysplasia do not have enamel defects, but demonstrate supernumerary teeth and delayed eruption of the permanent dentition.
The clinical features of Paget’s disease include enlargement of the jaws and “cotton wool” radiographic appearance of the bone
Patients with acromegaly may also have enlargement of the mandible and maxilla, with secondary separation of the teeth due to alveolar growth. The teeth themselves are unaffected in both Paget’s disease and acromegaly.
Cherubism- manifests itself in early childhood, often by the age of three or four years. The patient exhibits a progressive, painless, symmetric swelling of jaws, mandible or maxilla, producing a typical chubby face. The deciduous dentition may be spontaneously shed prematurely, beginning as early, as three years of age. The permanent dentition is often defective, with absence of numerous teeth and displacement and lack of eruption of those present. The oral mucosa is intact and of normal color.
Radiographic appearance- extensive bilateral destruction of bone of one or both jaws with expansion and severe thinning of the cortical plates. Numerous unerupted and displaced teeth are commonly seen, some of which may appear to be floating in cystlike spaces.
REF: Shafer , Hine and Levy, Oral Pathology, p. 641, 701.
Regizi, Sciubba, p.474
The etiology of recurrent herpes labialis is a virus residing in the
Correct answer is c.
Recurrent herpes infection of the mouth occurs in patients who have experienced a previous herpes simplex infection and who have serum antibody protection against another exogenous primary infection. In otherwise healthy individuals, the recurrent infection is confined to a localized portion of the skin or mucous membranes.
Recurrent herpes is not a reinfection but a reactivation of virus that remains latent in nerve tissue between episodes in a non-replicating state. Herpes simplex has been cultured from trigeminal ganglion (which is the gasserian ganglion) of human cadavers, and recurrent herpes lesions commonly appear after surgery involving the ganglion. Recurrent herpes may be caused by trauma to lips, fever sunburn, dental extractions, and menstruation. The virus travels down the nerve trunk to infect epithelial cells spreading from cell to cell to cause a lesion.
Studies have suggested several mechanisms for reactivation of latent HSV, including low serum IgA, decreased cell-mediated immunity, decreased salivary antiherpes activity, and depressed ADCC (antibody dependent cellular cytotoxicity) and interlukin-2 caused by prostaglandin release in the skin.
Geniculate ganglion is associated with the facial nerve.
REF: Burket’s Oral Medicine, J.B. Lippincott, 1994. pp30-31.
161. The most common location for the Adenomatoid Odontogenic Tumor (AOT) is:
a. anterior maxilla
b. posterior maxilla
c. anterior mandible
d. posterior mandible
e. midline of the mandible
“The adenomatoid odontogenic tumor (AOT) is uncommon, benign, and noninvasive and makes up approximately 3% of all odontogenic tumors. The origin is uncertain, but thought to arise from residual odontogenic epithelium... the AOT must be distinguished from the ameloblastoma because these two lesions differ radically in clinical, radiographic, and microscopic features and behavior. The AOT is a slow-growing tumor that does not infiltrate bone. These tumors are inclined to displace teeth rather than cause root resorption....it is almost twice as common in women and usually occurs in the second decade of life (teens), the average age being 17 y/o. At least 73% of these tumors occur in association with unerupted teeth or in the walls of dentigerous cysts. Approximately 90% have occurred in the anterior portions of the jaws: they are about 1 1/2 times more frequent in the maxilla than in the mandible.
The AOT is best treated by enucleation, since it separates easily and cleanly from its bony defect and does not show a tendency to recur....”
DIFFERENTIAL DIAGNOSIS of ORAL and MAXILLOFACIAL LESIONS: Norman K. Wood and Paul W. Goaz, 5th edition, chap 17, p. 289, 1997.
162. Hypercementosis is normally associated with
1. osteitis deformans (Padget’s disease)
2. occlusal trauma
a. only 1
b. 1, 2
c. 1, 3
d. 2, 3
e. all the above
“ Hypercementosis (cemental hyperplasia) has been defined by Stafne as ‘excessive formation of cementum on the surface of the root of the tooth.’ The early stages are only microscopically detectable, but as additional layers of cementum are added, the accumulation becomes apparent on the radiograph. The etiology of hypercementosis is not well understood, but repeated observations seem to indicate that this lesion is sometimes associated with the development of periapical inflammatory conditions, PCOD, occlusal trauma, and systemic disease (such as Paget’s disease, acromegaly, and gigantism, periapical granuloma )...”
DIFFERENTIAL DIAGNOSIS of ORAL and MAXILLOFACIAL LESIONS: Norman K. Wood and Paul W. Goaz, 5th edition, chap 27, p.466, 1997.
163. The vast majority of salivary calculi are found in the duct of which of the following glands?
d. minor salivary gland
e. equally in a and c
“ Sialoliths (Salivary Gland Calculi)... are calcareous (radiopaque) deposits in the ducts of the major salivary glands or within the glands themselves. They are thought to form from a slowly calcifying nidus of tissue or bacterial debris (organic matrix)... occurs mainly in the submandibular gland (80% to 90%) and to a lesser degree in the parotid gland (5% to 20%). Predilection for the submandibular gland and duct may result from gravity and the fact that the oral terminus is superior to the gland. The sublingual gland is involved in less than 1% of cases.”
DIFFERENTIAL DIAGNOSIS of ORAL and MAXILLOFACIAL LESIONS: Norman K. Wood and Paul W. Goaz, 5th edition, chap 27, p. 471, 1997.
164. Which of the following factors may predispose to the onset of candidiasis?
1. Alterations of normal oral flora by prolonged antibiotic therapy
2. Lowered host resistance resulting from disease or drugs
4. Long term anticoagulant therapy
a. 1, 3
b. 2, 4
c. 1, 2, 3
d. 1, 3, 4
e. All of the above
Candida albicans , a yeastlike fungus. Candida is an opportunistic organism that tends to proliferate with the use of broad-spectrum antibiotics, corticosteroids, medicines that reduce salivary output, and cytotoxic agents. Conditions that contribute to candidiasis include xerostomia, diabetes mellitus, poor oral hygiene, prosthetic appliances, and suppression of the immune system (i.e. AIDS or the side effects of some medications). It is important to determine the predisposing factors.
Ref. Little, JW. Dental Management of the Medically Compromised Patient. Fifth Edition, 1997, pg 628.
165. An erythrocyte count of less than two million per cubic mm would suggest that the patient has
e. Erythema multiforme
RBC Count: Male 4.6 - 6.2 million/cubic mm
Female 4.2 - 5.4 million/cubic mm
Anemia: A reduction in the oxygen-carrying capacity of the blood and usually is related to a decrease in the number of circulating red blood cells or to an abnormality in the hemoglobin contained within the red blood cells. Anemia is not a disease but rather a symptom complex that may result from decreased production of red blood cells (from Fe deficiency, pernicious anemia, folate deficiency), blood loss, or increased rate of destruction of circulating red blood cells.
Leukopenia: A lack of sufficient leukocytes (white blood cells).
Agranulocytosis: A reduction of or lack of neutrophils is the hallmark of agranulocytosis. Like many blood dyscrasias the decrease of granulocytes can manifest as primary (unknown etiology) or secondary (usually as a reaction to a drug or chemical compound).
Thrombocytopenia: Decrease in the number of circulating platelets. The primary form (idiopathic purpura) is conjectured to be of autoimmune etiology with an antiplatelet globulin identified in some but not all cases. The secondary form is precipitated by numerous agents among which are ionizing radiation, a wide spectrum of drugs, congenital disorders, infectious viruses and marrow replacing diseases.
Erythema multiforme: An acute dermatitis of unknown etiology but thought to perhaps be caused by antigen-antibody complexes in small superficial blood vessels. It is precipitated by numerous agents including HSV I, HSV II, sulfonamides, tuberculosis, histoplasmosis, barbiturates, vaccination. More commonly seen in young adult males, Classic “bull’s eye” lesions are seen most often on extremities. Orally, bullae quickly become superficial ulcers crusting with hemorrhagic slough.
Ref. Shafer, Hine, Levy. A Textbook of Oral Pathology, Fourth Edition, 1983.
Oral Pathology Class Notes, 1996.
166. A radiopaque periphery encircling a radiolucency is suggestive of a lesion that is
a. Slowly growing
b. Rapidly growing
c. Beginning to heal
d. Traumatically induced
e. Recently developed
A well-circumscribed, round roentgenolucency with a roentgenopaque border usually indicates that the lesion is slow growing or arrested; while an irregular, poorly demarcated area without an opaque lining suggests more rapid growth of an osteolytic lesion.
Ref. Mitchell DF, Standish SM, Fast TB. Oral Diagnosis, Oral Medicine, 1969.
Which of the following symptoms are associated with barbiturate overdose?
1, 2, 3
2, 3, 4
1 and 3
2 and 4
2 and 3
The barbiturates are safe and effective drugs when administered in hypnotic doses to normal persons. Untoward effects may arise in an occasional person as unexplained idiosyncrasies or in all persons as a result of acute or chronic overdosage. A few persons, particularly elderly persons, may exhibit idiosyncratic excitement instead of depression following the use of the barbiturates. A few may also show skin reactions, vague pains and aches, and gastrointestinal symptoms. The incidence of these unusual responses is extraordinarily low. Behind narcotics, barbiturate poisoning is one of the most common problems in toxicology. The cause of death in acute, overwhelming barbiturate poisoning is undoubtedly cessation of respiration as a consequence of depression of the respiratory center. If the ingested dose is not quite lethal or absorption from the gastrointestinal tract is delayed, the individual may survive for many hours or days. Under these conditions he will often be comatose, with respiration slow, skin and mucous membranes cyanotic, and various reflexes diminished or absent. Body temperature will be low, blood pressure may be diminished, and pupils may be somewhat constricted and may or may not respond to light.
Maintenance of adequate respiration and circulation should be the most important objectives in the treatment of acute poisoning. Medical Pharmacology, A. Goth, 1981, 10th ed. p. 311
168. A 34-year-old male presents for treatment of a painful infected tooth. He is asthmatic and takes 500 mg of Theophylline, BID. What medications should NOT be prescribed or recommended?
Erythromycin: macrolide antibiotic
Anacin: aspirin product
Excedrin PM: 500mg of acetominophen; 38 mg diphenhydramine citrate, an antihistamine
a. 1, 2, 3
b. 2, 3, 4
c. 2 and 3
d. 1 and 4
e. all of the above
Administration of aspirin-containing medication or other NSAIDs to patients with asthma is not advisable because aspirin ingestion is associated with precipitating asthma attacks in a small percentage of patients. Likewise, barbiturates and narcotics are best avoided as they also may precipitate an asthma attack, and these drugs should not be prescribed. Antihistamines should be used cautiously because of their drying effect. Patients taking theophylline preparations should not be given macrolide antibiotics (i.e., erythromycin and azithromycin) or ciprofloxacin hydrochloride, because this may result in a toxic blood level of theophylline. Dental Management of the medically compromised patient, Little, 5th ed. 1997. p.
Examples of Type IV allergic hypersensitivity reactions are:
extrinsic bronchial asthma
systemic Arthus reaction-- Type III
tuberculosis (Postive PPD test)
answer is (a), contact dermatitis and tuberculosis.
TABLE 22-17, Dental Management of the medically compromised patient, Little, 5th ed. 1997, p. 450
Type IV Hypersensitivity
1. Mediated by T lymphocytes
2. Antibodies not involved
3. Also called delayed-type hypersensitivity
a. Response not seen until about 2 days following antigenic exposure
a. Contact dermatitis
b. Graft rejection
c. Graft-versus-host reaction
d. Some types of drug hypersensitivity
e. Some types of autoimmune disease
Based on Thomson NC, Kirkwood EM, Lever RS: In Thomson
NC et al, editors: Handbook of Clinical Allergy, Oxford, 1990,
Blackwell Scientific, pp 1-36.
Type IV Hypersensitivity Reaction (Contact Dermatitis)
1. Allergen is usually a small chemical
a. Remains in skin 18 to 24 hours
b. Acts as hapten (most couple with protein)
2. Hapten-protein complex is processed by dendritic cells
3. Langerhans cells also involved as antigen presenting cells
a. Migrate to local lymph nodes
b. Processed antigen presented to undifferentiated T lymphocytes
c. Differentiation and proliferation produce
(1) T-effector cells
(2) T-memory cells
4. T-effector and T-memory cells recirculate
a. Patrol skin
b. Reaction occurs if some antigen still present or when antigen is presented again; inflammatory mediators released
5. Clinical features of reaction
b. Papulovesicular eruption
c. Vesiculation and weeping
Based on Thomson NC. Kirkwood EM, Lever RS: In Thomson
NC el al, editors: Handhook ~1" clinical allergy, Oxford, 1990,
Blackwell Scientificú pp 194-219.
170. The steroid with the highest potency is
Little, JW, Falace, DA, Miller, CS, Rhodus, NL, Dental Management Of The Medically Compromised Patient. 5th edition. Mosby-Year Book, Inc., pg 412.
Glucocorticoids and Their Relative Potency
Approximate equivalent dose (mg)
Short-acting (<12 hours)
Intermediate-acting (12 to 36 hours)
Long-acting (>36 hours)
171. Which of the following are associated with pernicious anemia?
Early onset in puberty
all of the above
Little, JW, Falace, DA, Miller, CS, Rhodus, NL, Dental Management Of The Medically Compromised Patient. 5th edition. Mosby-Year Book, Inc., pg 496.
Pernicious anemia is due to a deficiency of intrinsic factor, the substance secreted by the parietal cells of the stomach that is necessary for the absorption of vitamin B12, which is needed for the maturation of red blood cells.
…is usually a disease of late adult life. …most often occurs in 40-year-old to 70-year-old northern Europeans of fair complexion, with one notable exception. (early onset in black American women <40 years old)
…Early symptoms include weakness, fatigue, palpitations, syncope, tingling of the fingers and toes (paresthesias), numbness, uncoordination, and muscular weakness.
172. A 62 year-old woman is referred to you from her family physician because of painful, red, eroded gingiva that has not responded to supplemental vitamins and iron therapy. Your examination reveals several areas of erythematous gingiva as well as similar appearing lesions on her soft palate and cheeks. A white film is easily rubbed from the surface of some of the lesions. She has no skin lesions. Your differential diagnosis may include:
erosive lichen planus, hyperkeratosis, candidiasis
desquamative gingivitis, pemphigoid, erosive lichen planus, candidiasis, pemphigus vulgaris
lupus erythematosis, pemphigus vulgaris, angioneurotic edema, actinic keratosis
desquamative gingivitis, pemphigoid erosive lichen planus, chronic atrophic candidiasis, pemphigus vulgaris
erosive lichen planus, lupus erythematosis, pemphigus vulgaris, candidiasis
answer is (b).
Bhaskar, SN, Synopsis of Oral Pathology 5th edition, C. V. Mosby, 1977: pg 398.
Benign mucous membrane pemphigus (pemphigoid)
Notes from Oral Pathology
Age/Sex: Postmenopausal female
Clinical Features: Usually multiple areas of gray mucosa that are necrotic and peel off, leaving superficial ulcers; some cases have red raw appearance
Microscopic: Non specific superficial ulceration
Treatment: Lesions refractory to treatment, but disease does not endanger life; cortisone, estrogens, vitamin B complex have been tried.
173. Which of the following conditions is NOT a consideration in the “clinical staging” of a lesion?
A. Size and extent of primary lesion
b. Degree of infiltration by the primary lesion
c. Whether or not the nodes are fixed
d. Age of the patient at the time of the biopsy
e. Clinically palpable lymph node involvement
In the TNM method of staging lesions the following things are considered.
T-1 tumor less than 2 cm
T-2 tumor between 2 and 4 cm
T-3 tumor greater than 4 cm
N-Regional lymph nodes
N-0 nonpalpable nodes no mets expected
N-1 palpable homolateral nonfixed nodes mets suspected
N-2 palpable contralateral nonfixed nodes mets suspected
N-3 fixed nodes mets suspected
M-0 No distant metastasis
M-1 Evidence of metastasis to other than cervical nodes
Referance: Oral Pathology notes; Oral Cancer, Silverman, ed. 1981, p 76.
174. Successful Hepatitis B immunization is demonstrated by the production of
a. Hepatitis B core antibody
b. Hepatitis B surface antibody
c. Hepatitis B surface antigen
d. Hepatitis B e antigen
e. Hepatitis B core antigen
The Anti-HBc is positive in all acute and chronic cased and in carriers: a marker for infection not protective
Anti-HBs shows previous exposure to HBV: previous vaccination: recent HBIG prophalaxis. Usually indicates protection. When present with the HbsAG, indicates chronic hepatitis.
HBsAg indicates acute or chronic infection
HBeAG Transiently positive is acute hepatitis and is some chronic carriers. Not protective, reflection of low infectivity.
Reference: Oral Medicine handout; Harrison’s Principles of Internal Medicine, 12th ed, p 1333.
175. A patient on therapeutic doses of aspirin can best be screened for a potential bleeding problem by an evaluation of the
a. Bleeding time
b. Platelet count
c. Coagulation time
d. Prothrombin time
e. Partial thromboplastin time
Aspirin affects the platelets by rendering them “not sticky” for the life of the platelet. The average platelet is circulating for 8-12 days before it is destroyed. The effect of aspirin is measured by a bleeding time test. The platelet count measures the number of circulating platelets only it does not assess the function. A patient on aspirin would have a normal number of platelets but the function would be impaired. Prothrombin time is used to check the extrinsic pathway it has nothing to do with aspirin. PTT is used to monitor the intrinsic pathway and again has no relationship to aspirin.
Ref: Sonis, Fazio, and Fang: Principles and Practice of Oral Medicine, W. B. Saunders Co, 1984, p. 298-304, 318.
176. Comparing the use of ultrasonics vs. hand scalers in initial preparation, studies have shown that both are equally effective:
1. in removing calculus
2. in planing the root
3. in removing endotoxin
a) 1 only
b) 2 only
c) 1 and 2
d) 1 and 3
e) all of the above
1. Recent scientific evidence provides credible evidence for using power driven instrumentation. (PDI)
as part of a non-surgical therapeutic regimen.
2. Power driven instrumentation is as effective as traditional hand instrumentation in removing supra- and subgingival calculus.
3. Literature demonstrates that ultrasonic activity is antimicrobial in nature and can remove bacterial endotoxin lodged in root surfaces.
Ultrasonic debridement was significantly more effective than hand scaling in Class II and Class III furcations; Why? The angulation is difficult to attain with hand instruments.
Advantages of Using Ultrasonics
-Size and shape of the tips
-Effectiveness on all surfaces with any stroke
-Use with a light touch, does not require a firm finger rest
-Causes less soft tissue trauma and distention
-Pocket irrigation, washed field, visibility, and possible bacteriociodal effect
-Increased patient comfort and acceptance
-Requires less time
-Less tiring for the operator
Disadvantages of Using Ultrasonics
- Less tactile sense of the root surface
-Produces micrscopic rippling of the root surface
-Requires high speed evacuation
-Produces contaminated aerosol
-Wear not only a mask but a shield and pre-rinse every patient with chlorhexidine
- Possible risk to patients with pacemakers
- Less readily portable (equip each hygiene operatory with one!)
HOW TO PUT ULTRASONICS INTO YOUR PRACTICE
I would never use a scaler again for gross scaling. A large P-10 ultrasonic tip is recommended.
I would use modified P-10 straight R and L’s, but for anything over 4mm I would use a thin Gracey
If you are deplaquing, 90% of cases could be treated with modified ultrasonic tips. If I felt uncomfortable with certain areas, I might go over those areas with thin Gracey instrumentation.
Ref: Low, Samuel B., DDS, MS, MEd, University of Florida, College of Dentistry, Periodontal Disease Management, A Conference for the Dental Team, Boston, Massachusetts, July 1993, p. 303-310
177. The histological base of a periodontal pocket may be defined as the
a) apical level of the periodontal fibers
b) apical level of the junctional epithelium
c) coronal level of the periodontal fibers
d) coronal level of the junctional epithelium
e) apical to the junctional epithelium
The periodontal probe is used primarily to measure the pocket depth and probing attachment level.
Probing pocket depth is the distance between the gingival margin and the apical depth of the periodontal probe tip penetration.
Periodontal pocketing is a consequence of the late established and the advanced lesions and is caused by destruction of the coronal end of the junctional epithelium and collagen fiber attachment to the root surface at the apical end of the junctional epithelium.. this allows apical migration of the junctional epikthelium, and deepening of the periodontal pocket.
The anatomic(histologically determined) gingival sulcus (pocket) extend from the gingival margin to the coronal end of the junctional epithelium.
Ref: Caton, Jack, Periodontal Diagnosis and Diagnostic Aids, Proceedings of the World Workshop in Clinical Periodontics, July 23-27, 1989,p. I-6
178. A furcal involvement of which of the following teeth has the LEAST favorable prognosis for successful periodontal treatment?
a) maxillary first molar
b) maxillary second molar
c) maxillary first premolar
d) mandibular first molar
e) mandibular second molar
Reference: Perio Lit Rev. 1996, Pg 83
Prognosis for teeth with furcation invasions depends on:
1. Extent of bone destruction horizontally and vertically in the interradicular space.
2. Number of roots and their morphology.
3. Morphology of the interradicular space. A) Width. b) Depth.
4. Condition of the periodontal attachment as determined by clinical mobility tests and percussion.
5. Access for surgical correction of the deformity.
6. Patient’s access for oral hygiene after therapy.
Mandibular molars with furca invasions usually have a more favorable prognosis than maxillary molars with furca invasions because of better access for oral hygiene. If root anatomy is favorable, that is, if there is adequate length and divergence, mandibular molars can be cleaned through the furca when septal bone loss is extreme. The complicated anatomy of a maxillary molar trifurcation makes prognosis poor when septal bone loss extends through the interfurca from one surface to another.
Mandibular second molars with furcation invasions usually have a less favorable prognosis than first molars since their roots are shorter and the interradicular space is constricted
Maxillary first bicuspids usually have a single root but may have a buccal and a lingual root. Invasion of periodontal disease in the furcation of these teeth causes a poor prognosis because of the inaccessibility of the furca for oral hygienic measures. Furcation is so low on root, 7.9 mm is average CEJ to furcation. Average CEJ to furcation for maxillary molars is 3.6, 4.2 and 4.8 mm on mesial, facial and distal surfaces. (Ref Periodontal Lit Review, AAP 1996, page 83)
Maxillary first molars with furca invasions usually have a favorable prognosis if septal bone is still present in the interfurca. Furcation invasions on the mesial aspect or on the buccal aspect have a favorable prognosis since they are accessible for surgical resculpturing that makes adequate oral hygiene possible. Furca invasions on the distal aspect of these teeth are generally hopeless because of the inaccessibility to oral hygiene. However if the tooth is the terminal one in the arch and the patient practices scrupulous oral hygiene, a distal surface furcation may have a favorable prognosis.
Pronosis for the maxillary second molar with a furca invasion is less favorable than for a similar invasion of the first molar because of the second molar’s smaller root structure, restricted interradicular space, and more distal position in the arch.
However, these statements do not constitute rules: prognosis must be determined individually for each tooth.
Ref: Prichard, John F., Advanced Periodontal Disease, Surgical and Prosthetic Management,
W.B.Saunders Company 1972, p.262-273
179. The positive correlation between the presence of calculus and the presence of gingivitis is greater than the correlation between plaque and gingivitis. The surface plaque on calculus is thought to be the principle irritant in the periodontal pocket, not the calculus itself.
A. Both statements are TRUE
B. Both statements are FALSE
C. The first statement is TRUE, the second is FALSE
D. The first statement is FALSE, the second is TRUE
Plaque is more important than calculus in the etiology of gingival and periodontal disease. Gingivitis occurs in the absence of calculus and the formation of plaque leads to gingivitis which disappears when the plaque is removed.* It is difficult to separate the effects of calculus and plaque upon the gingiva, because calculus is always covered with a nonmineralized layer f plaque. There is a positive correlation between calculus and the prevalence of gingivitis, but it is not as high as between plaque and gingivitis.
Glickman, Clinical Periodontology, 4th Edition, 1972, p308.
(Classic question - classic answer)
* The most recent edition of Glickman, ( 7th) does not specifically address this question as well, but it does address a newer important concept. Gingivitis is not just a consequence of plaque accumulation per se but requires a sequential process with colonization of additional species ( good plaque/ bad plaque). This question is actually somewhat outdated.
180. Loss of gingival attachment may be associated with which of the following conditions?
2. A periodontal pocket extending apically beyond the mucogingival line
3. Superficial, heavy accumulation of calculus
4. Tension from frenal and muscular attachments
Reduced or absent attached gingiva may be due to several factors:
1. The base of the periodontal pocket being apical or close to the mucogingival line
2. Frenal and muscle attachments that encroach upon periodontal pockets and pull them away from the tooth surface. Tension from attachments (a) distends the gingival sulcus and fosters the accumulation of irritants that lead to gingivitis and pocket formation, and (b) aggravates the progression of periodontal pockets and causes their recurrence after treatment.
3. Recession causing denudation of root surfaces and creating a functional as well as an esthetic problem.
Glickman, Clinical Periodontology, 7 edition, 1990, p.878-879.
181. Bleeding associated with chronic marginal gingivitis occurs because:
1. A lack of vitamin C affects capillary permeability
2. The periodontium is easily injured by tooth brushing
3. The epithelium of the lateral wall of the gingival sulcus contains microulcerations
4. The epithelial attachment is destroyed and vessels from the periodontal ligament are injured
5. Plaque induced inflammation increases the permeability of the sulcus epithelium by degrading intercellular cement substance.
In gingival inflammation, the following histopathologic alterations result in abnormal gingival bleeding: dilation and engorgement of the capillaries and thinning or ulceration of the sulcular epithelium. Because the capillaries re engorged and closer t the surface and the thinned, degenerated epithelium is less protective, stimuli that are ordinarily innocuous cause rupture of the capillaries and gingival bleeding.
Analysis of the literature indicates that patients with acute or chronic vitamin C - deficient states and no plaque accumulation show minimal, if any, changes in their gingival status. Gingivitis is not caused by Vitamin C deficiency per se.
Glickman states on page 436 the possible etiologic relationships of Vitamin C and periodontal disease. Vitamin C deficiency results on defective formation and maintenance of collagen, retardation or cessation of osteiod formation and impaired osteoblastic function. Vitamin C deficiency is also characterized by increased capillary permeability, susceptibility to traumatic hemorrhages, hyporeactivity of the contractile elements of the peripheral blood vessels, and sluggishness of blood flow. Because the question reflects a causal relationship between Vitamin C deficiency and bleeding I am tempted to include (1) as a correct answer.
The question specifically addresses the bleeding associated with chronic marginal gingivitis and while laceration of the gingiva by toothbrush bristles can cause bleeding they are not part of the gingivitis, per se.
The destruction of the epithelial attachment and resultant injury of the vessels of the periodontal ligament is a description of periodontitis not gingivitis.
A maxillary canine that requires a crown has insufficient zone of attached gingiva for the planned treatment. The best preposthetic treatment would be
a localized gingivectomy
a free gingival autograft
curretage and root planing
apically repositioned flap
a regenerative surgical procedure with DFDBA
Correct answer is b.
Gingivectomy- is the excision of the soft tissue wall of the periodontal pocket which may be accomplished by either an external or internal bevel. This surgical procedure which is aimed at “pocket elimination” was usually combined with recontouring of diseased gingiva to restore physiological form.
page 399 Lindhe.
Free gingival graft- (autogenous gingival graft)- Free grafts of gingiva or palatal mucosa and subepithelial connective tissue grafts are utilized to increase the zone of gingiva at the buccal or lingual aspects of a single tooth or a group of teeth. In addition, free grafts of gingiva or palatal mucosa are used to cover gingival recessions when these are relatively narrow and there is no acceptable donor tissue present in adjacent areas. Page 442 Lindhe
Indications for a free gingival graft to increase the band of attached gingiva. The strengths of free gingival grafts to increase the band of attached gingiva are that it can be done for a single tooth or groups of teeth with very high predictability of success. There is a relatively limitless source of donor tissue as compared with that for pedicle grafts. It can be done prophylactically with exceedingly little chance of failure. It has the disadvantage of requiring two surgical sites (e.g. donor and receptor ) when compared to pedicle grafts, and it is limited by its usefulness in esthetically important areas by the need for color and texture match between donor and receptor sites. WWP 1989
Defintion of success. A successful free gingival graft to create an adequate band of attached gingiva does exactly that. It is not a numerically measurable amount of attached gingiva but enough , in the individual clinicians opinion, to permit completion of the desired treatment plan without jeopardizing the attachment level on tooth by instigating recession. WWP 1989
Curettage and root planing-
Scaling is defined : Instrumentation of the crowns and root surfaces of the teeth to remove plaque, calculus, and stains from these surfaces.
Root planing (root curetage): A definitive treatment procedure designed to remove cementum or surface dentin that is rough, impregnated with calculus, or contaminated with toxins or microorganisms. When done in a thorough fashion, some unavoidable soft tissue removal occurs. WWP 1989.
Gingival Curettage- (Closed gingival curettage): The surgical procedure of debriding the soft tissue wall of a periodontal pocket by means of a currette. Root instrumentation is routinely accomplished in conjunction with the procedure. WWP 1989
Apically repositioned flap-In the 1950s and 1960s new surgical techniques for removal of soft and, when indicated, hard tissue periodontal pockets were described in the literature. The importance of maintaining “ an adequate zone of attached gingiva” after surgery was now emphasized. One of the first authors to describe a technique for preservation of a zone of keratinized and attached gingiva following surgery was Nabers (1954). The surgical technique developed by Nabers was originally denoted “repositioning of attached gingiva”. In 1962 Friedman proposed the term “apically repositioned flap. Friedman emphasized the fact that , at the end of the surgical procedure, the entire complex of the soft tissue (gingiva and alveolar mucosa) rather than gingiva alone was displaced in the apical direction. Thus, rather than excising the amount of gingiva which would be in excess after osseous surgery (if performed), the whole mucogingival complex was maintained and apically repositioned. Page 405,Lindhe
Advantages of apically repositioned flap procedure:
Minimum pocket depth postoperatively
If optimal soft tissue coverage of the alveolar bone is obtained, the post surgical bone loss is minimal.
The postoperative position of the gingival margin may be controlled and entire mucoginvial complex may be maintained. Page 407 Lindhe
Apically Positioned Flap
Apically positioned flap without osseous surgery- is a full or partial thickness surgical flap that is moved to an apical position without osseous resection. WWP 1989.
Apically positioned flap with osseous surgery- is a full or partial thickness surgical flap that is moved to an apical position an ideal or less than ideal osseous profile, accomplished by osseous resection . WWP 1989
Regenerative Procedure with DFDBA ( demineralized freeze dried bone allograft)
Periodontal regeneration (definition)- architecture and function of the completely restored , with new alveolar bone, new PDL, and cementum.
Indications. The need to maintain or increase bone support.
Favorable defect morphology
Objectives: Clinical attachment gain
Bone fill of defect
Histologic Regeneration: new bone, cementum, PDL.
Best success is with narrow 3 wall defects.
Least predictable success: furcations, horizontal defects. Periodontics class notes.
REF: LINDHE, JAN, Textbook of CLINICAL PERIODONTOLOGY. 2nd edition, Munksgaard Publishing Co. 1989
Proceeding of the World Workshop in Clinical Periodontics. 1989
Class notes Periodontal Course, Lecture Regenerative Periodontal Surgery 1996.
183. Which of the following is considered and absolute contraindication to periodontal surgery?
oral anticoagulant therapy
reduced adrenal function
Correct answer is d.
Arterial hypertension does not normally preclude periodontal surgery. The patient’s medical history should be checked for previous untoward reaction to local anesthesia. Local anesthesia free from or low adrenaline may be used and aspirating syringe should be adopted to safeguard against intravascular injections.
Angina pectoris does not normally preclude periodontal surgery. The drugs used and the number of episodes of angina may indicate the severity of the disease. Premedication with sedatives and the use of local anesthesia low in adrenaline are often recommended. Safeguards should be adopted against intravascular injections.
Anticoagulant treatment implies increased propensity for bleeding. Periodontal surgery should be scheduled after consultation with physician. Salicylates should not be used for postoperative pain control since they increase bleeding tendency.
Patients suffering from acute leukemia’s, agranulocytosis and lymphogranulomatosis must not be subjected to periodontal surgery due to patient’s inability to fight off infections.
Anemias in mild and compensated form do not do not preclude surgical treatment. More severe and less compensated forms may entail lowered resistance to infection and increased propensity for bleeding.
In such cases, periodontal surgery should be performed after consultation with patient’s physician.
Adrenal function may be impeded in patients receiving large doses of corticosteroids over an extended period. These conditions involve reduced resistance to physical and mental stress, and the doses of corticosteroid may have to be altered during the period of periodontal surgery, The patient’s physician should be consulted.
Diabetes mellitus entails lowered resistance to selection, propensity for delayed would healing and predisposition for arteriosclerosis . Well compensated patients may be subjected to periodontal surgery provided precautions are taken not to disturb dietary and insulin routines.
REF: LINDHE, JAN, Textbook of CLINICAL PERIODONTOLOGY. 2nd edition, Munksgaard Publishing Co. 1989. Pages 392-393.
The rational for periodontal maintenance interval is based upon the
rate of calculus deposition
complexity of initial periodontal treatment
need to disrupt subgingival microflora
extent to which tissue were apically positioned
type of surgical procedure performed
Correct answer is c. With 3 month professional cleaning, the level of oral hygiene was not critical fro maintenance (Ref Ramfjord, J Periodontology 1982)
Following the final evaluation of the patient at the conclusion of the maintenance visit, the doctor must determine the proper time interval for the next appointment. A number of factors aid in this determination, the most important critical criterion being the state of the patients periodontal health at maintenance. Periodontal health at maintenance is most accurate indicator because it represents the longest time that the patient has been without professional care. Many reports have emphasized that the patient’s ability to control plaque should be a strong determining factor in establishing the maintenance interval.
No general rule regarding frequency of maintenance can be provided for individuals who have received active treatment for moderate to advanced periodontitis. Survey of dental hygienists suggest that hygienists employed by generalists (don’t you just love that word) in the United States usually recall patient at 6 month intervals, while periodontally employed hygienists report a frequency of 4 months for maintenance. Many studies indicated that a period of 2 to 4 months is sufficient to maintain health for most individuals. Some patient with good oral hygiene and periodontal health require less frequent appointments while other will need tighter maintenance schedules.
REF: Proceeding of the World Workshop in Clinical Periodontics. 1989, Section IX, page 14.
An inconsistency in the various reports exists regarding the effect of personal hygiene. While it is clear to any one involved in periodontal therapy that the better the personal plaque control the better the result, it is now clear that perfect plaque control , the better the result, it is not clear that perfect plaque control must exist to have a generally successful result (Ramfjord et al., 1982). The Minnesota, Michigan , and Aarhus studies reported that patients with imperfect plaque control fared as well in terms of attachment level results , as well as patients with high plaque control scores. The Gothenburg studies reported that plaque free sites did not lose attachment while plaque associated sites tended to lose attachment, The Aarhus studies reported that the Gothenburg studies performed only supragingival tooth cleaning at maintenance visits while the Minnesota, Michigan, Aarhus groups performed subgingival cleaning during maintenance. The subgingival cleaning apparently helps disrupt the subgingival ecosystem and reduce the pathogenicity of the flora, thereby minimizing attachment loss even in the face of imperfect patient performed oral hygiene efforts. This means that subgingival instrumentation is absolutely essential at maintenance visits.
REF: Periodontal Literature Reviews a summary of current knowledge. Chapter 8, page 136, 1996.
With professional tooth cleaning every 3 months, the pocket reduction and clinical attachment level gained by therapy can be maintained without significant effect from variations in personal oral hygiene
(less than perfect oral hygiene).
REF: Ramfjord et al., Oral Hygiene and Maintennce of Periodontal Support. J Periodontol 53: 26 1982.
185. Which of the following statements correctly describes the periodontal ligament (PDL)?
1. dense connective tissue of the PDL attaches the tooth to the alveolar bone
2. the tooth is supported in the alveolus by the PDL
3. the PDL maintains the physiologic relation between cementum and bone
4. the PDL exhibits nutritive properties.
a) 1, 2
b) 1, 3
c) 1, 2, 3
d) 2, 3, 4
e) all of the above
Basically the definition of the PDL according to Chapter 2, pp 39-49 of GLICKMAN’S CLINICAL PERIODONTOLOGY: Carranza, Seventh Edition, 1990.
186. Occlusal factors which have been found to correlate with increased severity of periodontal disease include
a) balancing contacts
b) cross tooth working excursion contacts
c) cusp fracture and severe occlusal wear
d) mobility and widening of the periodontal ligament
e) porcelain to enamel occlusal contacts
What the author of this question really meant to ask was: “occlusal signs or symptoms”
then the answer marked above would be correct:
“Hyperfunction, seen in some instances, is characterized by a thickened periodontal ligament with an increased number of principle fibers, a thicker alveolar plate, and more condensed supporting bone. Abnormal forces (Luke, let the force take you) that exceed the physiological tissue limits may result in the change known as occlusal traumatism. The lesion of occlusal traumatism may be defined as a destructive, dystrophic response of the attachment apparatus to adverse occlusal load. Symptoms and changes associated with the lesion of primary occlusal traumatism have been discussed histologically, clinically, and reontgenographically in previous chapters but will be reviewed now.
Histological changes include thrombosis of the vessels, ischemia of the periodontal ligament, hyalinization of the principle fibers, necrosis of the periodontal ligament, absorption of the alveolar bone, absorption of the root of the tooth, and cemental tears.
Clinical signs include increased mobility of the tooth, tenderness of the tooth, migration of the tooth, and incomplete or complete fracture of the crown or root.
Roentgenographic signs include thickening of the periodontal ligament space, loss of definition of the periodontal ligament space, loss of continuity of the osseous tissue wall lining the alveolus (so-called lamina dura), root resorption, and osseous resorption.”
PERIODONTAL THERAPY: Goldman, Henry M., Cohen, D. Walter, sixth edition, 1980, pp 1066-1068.
The REAL ANSWER to this question as asked, is: there ain’t no answer as stated :
“It is not possible at present on the basis of the available evidence, to draw any firm conclusions about the role of occlusal trauma in progressive disease in humans. Further carefully controlled research in humans is necessary to confirm the claimed effects and without this support, the rationale for occlusal therapy in the management of progressive plaque-induced disease must be deemed to be questionable (see also Polson, 1980; Ramfjord and Ash, 1981)”
PERIODONTICS: A PRACTICAL APPROACH: Kieser, J. Bernard, 1990, chapter 33,
187. An apically positioned flap is used to
1) achieve primary closure during osseous regenerative procedures
2) eliminates pockets by positioning the gingiva apically
3) increase the zone of attached gingiva
4) expose additional root surface for restorative procedures
1, 3, 4
2, 3, 4
all of the above
REFERENCE: DENTAL CLINICS OF N. A. 1976, JOHNSON.
The reason for placing the apically positioned flap is: “ This technique with some variants can be used for one or both of the following purposes: pocket eradication and widening the zone of attached gingiva. “
according to Chapter 57, pp 819 of GLICKMAN’S CLINICAL PERIODONTOLOGY: Carranza, Seventh Edition, 1990.
1) not used a method for primary closure during osseous regenerative procedures because the flap is usually placed at or coronal to starting position, not apically.
4) This is called a mini-flap procedure, used primarily in restorative procedures and not the primary reason for the apically positioned flap, as stated on page 819. (but to me a possible reason, if you want possible)
188. Which of the following are true about saliva?
1. IgA is the predominant immunoglobulin present
2. Protein concentration is greater than blood protein
3. 99% water, 1% organic and inorganic compounds
4. Neutralizes most acids produced by bacteria through its buffering action
5. Contains enzymes which initiate the digestive process
e. All of the above
REFERENCE: GRANT, 1979 - Periodontics.
Saliva, like sulcular fluid, contains antibodies that are reactive with indigenous oral bacterial species. Although IgG and IgM are present, the predominant immunoglobulin found in saliva is IgA, whereas IgG is more prevalent in sulcular fluid.
Saliva exerts a major influence on plaque by mechanically cleansing the exposed oral surfaces, by buffering acids produced by bacteria, and by controlling bacterial activity.
The enzymes normally found in the saliva are derived from the salivary glands, bacteria, leukocytes, oral tissues, and ingested substances; the major enzyme is parotid amylase. Certain salivary enzymes have been reported in increased concentrations in periodontal disease: these are hyaluronidase and lipase, beta-glucuronidase and chondroitin sulfatase, amino acid decarboxylases, catalase, peroxidase, and collagenase.
Coating similar to gastric mucin
Coating similar to gastric mucin
Clearance of debris and bacteria
Bicarbonate and phosphate
Tooth integrity maintenance
Control of bacterial colonization
Breaks bacterial cell walls
Oxidation of susceptible bacteria
Ref. Glickman’s CLINICAL PERIODONTOLOGY Seventh Edition 1990: 100-01
189. The consensus of the literature demonstrates that in periodontal probing (standard probing forces and standard probe size)
1. In health, the probe tip is found coronal to the connective tissue attachment
2. In diseased tissues, the probe tip is found within the connective tissue
3. In advanced periodontitis, the probe tip penetrates to the crest of the bone
4. In inflamed tissues, the probe tip penetrates the connective tissue, giving false attachment levels
d. 1 and 2 only
e. All of the above
Measurements recorded with a periodontal probe can no longer be used synonymously with “sulcus depth” or “pocket depth”, since probing seldom records accurately the depth of these anatomic entities. Probing in diseased tissue penetrated to the apical extent of the junctional epithelium and into the connective tissue to the level of intact connective tissue fibers (about 0.25-0.4 mm apically). Minimal penetration of the junctional epithelium is found in healthy tissues.
Ref. Listgarten MA: Periodontal Probing: What Does It Mean? J Clin Periodontol 1980. 7:165-176.
190. Which is true of guided tissue regeneration?
1. It delays epithelial migration along the root surface
2. Allows regenerative cells to originate form the gingival connective tissue
3. Involves placement of membrane to exclude undesirable cells during healing process
4. Allows for healing by long junctional epithelium
5 Regenerative cells originate form bone and PDL
6. Results in a new connective tissue attachment with some bone formation
In 1970’s, Melcher demonstrated that a barrier membrane could be used to allow selective cellular repopulation of the root surface during periodontal regeneration procedures. The theory was that the membrane would retard apical migration of the epithelium, exclude gingival connective tissue cells from the wound, and have undifferentiated mesenchymal cells from the periodontal ligament and bone to form a new connective tissue attachment mechanism.
Gottlow, Nyman and Lindhe also demonstrated that a new connective tissue attachment apparatus is formed by the use of a membrane thereby excluding the epithelium from proliferating and allowing cells from the PDL and bone to populate the area.
Ref. Melcher AH. On the repair potential of periodontal tissues. J Periodontol 1976;47:256-260.
Gottlow J, Nyman S, Lindhe J, Karring T and Wennstrom J. New Attachment Formation in the Human Periodontium by Guided Tissue Regeneration. J Clin Periodontol 1986; 13:606-616.
191. Chlorhexidine is thought to
alter the cell membrane of bacteria
be effective due to its substantivity
be bactericidal due to causing precipitation of cytoplasmic contents
have pronounced effect on the subgingival microflora (only if take special measures to get it in sulcus)
causes epithelial desquamation
increases surface staining of composite restorations
1,2.3,5,6 (this is the answer unless special measures are taken to get it in sulcuses)
all of the above (assuming subgingival irrigation in #4 )
Chlorhexidine digluconate (CHX) Peridex®, Periguard®
Two daily rinses with 15 ml of a 0.12% solution provide clinical benefits almost identical to the 0.2% solution (Segreto et al. 1986). However, when lower concentrations of the compound are used in oral rinses, less potent clinical effects can be anticipated (Lang et al. 1986).
The excellent results achieved in short-term clinical trials with chlorhexidine were also observed in several long-term studies. In the first or these studies (Loe et al. 1976), 150 medical students rinsed daily for 2 years with a solution of 0.2% chlorhexidine digluconate. Although interaction with a flavoring agent reduced the effective concentration of chlorhexidine, significant reductions in plaque, gingivitis, total numbers of facultative and anaerobic bacteria and Mutans streotococcus in the saliva were observed (Schiött et al. 1976). Based on these data, it seems reasonable to claim that chlorhexidine can safely be used for extended periods of time. Chlorhexidine adsorbs to the surfaces of oral tissues including the teeth, and is then slowly released in active form (Lang & Brecx 1986). Approximately 30% of a 10 ml solution of 0.2% chlorhexidine will bind to the oral surfaces. The cationic chlorhexidine molecule binds to anionic compounds such as free sulfates, carboxyl and phosphate groups of the pellicle, and salivary glycoproteins. This is known as substantivity (Rö11a & Melsen 1975) and will thereby reduce the adsorption of proteins to the tooth surface required for the formation of dental pellicle. Coating salivary bacteria with chlorhexidine molecules also alters the mechanisms of adsorption of bacteria to the tooth (Rö11a & Melsen 1975). Chlorhexidine molecules bound to salivary proteins will be released in active form in 8-12 hours (Bonesroll et al. 1974). Low concentrations of chlorhexidine can still be recovered after 24 hours. Chlorhexidine is active against Gram-positive and Gram-negative microorganisms and yeast cells. Because of its high cationic nature, chlorhexidine has a great affinity for the cell wall of microorganisms and changes the surface structures. Osmotic equilibrium is lost and, as a consequence, the cytoplasmic membrane is extruded, vesicles are formed, and the cytoplasm precipitates (Davies 1973, Brecx & Theilade 1984). These precipitations inhibit the repair of the cell wall, and the bacteria are no longer able to recover. The most common side effect of chlorhexidine is the formation of an extrinsic yellow-brown stain on teeth and tongue (Löe & Schiött, 1970). The degree of staining seems to depend on the concentration of the compound and varies greatly from one individual to another (Heyden 1973). Stain can appear on natural teeth, artificial teeth and composite restorations. In vitro (Addy et al. 1979) and in vivo (Prayitno et al. 1979) studies have demonstrated that tannin-containing substances such as tea, red wine, and port wine will increase the level of chlorhexidine discoloration. Desquamations and painful lesions occurred in some subjects using a 0.2% chlorhexidine digluconate solution in a 4-month clinical study. However, such lesions have not been found in studies using concentrations of less than 0.2%. Furthermore, a quality-specific impairment for salty taste perception which appear to be short-lasting has been found (Lang et al. 1988), indicating that chlorhexidine rinses should be applied after meals or before retiring at night. In order to affect the subgingival microbiota, sustained release devices (SRD) were developed. Such devices used ethyl cellulose and polyethylene glycol as polymers and chlorhexidine and ethanol as solvents (Friedman & Golomb 1982). The SRD's which contained 30% of the dry weight of chlorhexidine were placed in periodontal pockets. Over a period of 6 days approximately 50% of the chlorhexidine was released into the subgingival area, thereby reducing the relative proportions of the motile organisms, including spirochetes, to negligible levels (Soskolne et al. 1983, Stabholz et al. 1986).
Textbook of Clinical Periodontology 2nd Ed. Lindhe, pp. 372-376
192. It is likely that cell mediated immune reactions (delayed hypersensitivity) occurs in periodontal disease because subjects with periodontitis often have
IgA antibody reactive with plaque bacterial antigens
T-lymphocytes sensitized to plaque bacterial antigens
high levels of collagenase in gingival fluid
soluble immune complexes with involved gingival tissues
high levels of IgG complexes in gingival connective tissues
Periodontal lesions exhibit many of the classical microscopic features of so-called cell-mediated inflammatory diseases. These features include: a) infiltration of the lesion by mononuclear leukocytes (macrophages, lymphocytes and plasma cells); b) destruction of normal connective tissues; c) replacement of destroyed cells and tissues by proliferating fibroblasts and small blood vessels (fibrosis). Tissue destruction and fibrosis in delayed hypersensitivity appear to be largely mediated by T lymphocytes and macrophages which elaborate a variety of effector molecules. These mediators have pro-inflammatory functions and also modulate connective tissue metabolism, resulting in destruction as well as formation of excessive amounts of connective tissue matrices (Wahl 1986). The interplay of lymphocytes and macrophages represents a very important area for research in explaining the pathogenesis of established and advanced stages of periodontal disease, but at present there is only a very limited understanding of the molecular mechanisms to explain how these cells function to protect as well as damage the periodontium.
Numerous studies demonstrate that periodontal patients have circulating lymphocytes which are sensitized to substances originating from subgingival plaque organisms (Ivanyi & Lehner 1970, Lang & Smith 1977, Reed et al. 1976). In any event, it is likely that periodontal lesions contain subpopulations of T cells which have been sensitized and are responding to different plaque antigens (O'Neill, Woodson & Mackler 1982, O'Neill & Woodson 1986). Sensitized T lymphocytes are produced following initial exposure of the lymphoid system to antigens, and upon reexposure to these antigens they respond by proliferating and synthesizing lymphokines. It is clear that lymphokines serve as signals which stimulate, inhibit or even kill numerous types of cells. The participation of macrophages is crucial to the development of cell-mediated hypersensitivity reactions. Upon being recruited into inflammatory lesions, macrophages become activated under the influence of lymphokines and other substances, such as endotoxin and bacterial cell walls. When compared to resting cells, activated macrophages adhere more avidly to various substrates, phagocytose and kill bacteria more efficiently and also acquire cytotoxic properties enabling them to destroy tumor as well as other eukaryotic target cells.
Textbook of Clinical Periodontology 2nd Ed. Lindhe, pp. 185
REFERENCE: Glickman - “Host Response & Perio Disease”
193. Which of the following statements is FALSE?
In the advanced lesion, bone marrow distant from the lesion may be converted to fibrous
The established lesion shows scarring and fibrosis, and can persist for several months without
In the established lesion, plasma cells predominate, and lateral extension of the junctional
epithelium may begin.
In the early lesion, plasma cells predominate and early pocket formation may be evident.
In the advanced lesion, periods of quiescence and exacerbation are seen, along with
cytopathologically altered plasma cells.
The initial gingival lesion
Inflammation quickly develops as plaque starts to be deposited on the tooth. Within 24 hours marked changes are evident in the microvascular plexus beneath the junctional epithelium. More blood is brought to the area as manifested by dilation of the arterioles, capillaries and venules of the dentogingival plexus. At the same time, the hydrostatic pressure within the microcirculation is elevated coupled with the formation of intercellular gaps between adjacent capillary or venular endothelial cells. This results in a profound increase in the permeability of the microvascular bed to fluids and proteins which leak into the tissues. These changes represent an important defense reaction. For example, the outward flow of edema fluid from the blood into the tissues and gingival sulcus may dilute irritants (such as microbial toxins) and flush bacteria and their products from the sulcus into the oral cavity. Plasma proteins escaping from the microcirculation include fibrinogen, immunoglubulins, specific antibodies, complement peptides and albumin. In the non-inflamed gingival unit very little fluid is available, but during all phases of gingivitis the amount of exudate can be used as one index of inflammatory injury.
The early gingival lesion
During the 4-7 day interval after microbial colonization, the vessels of the coronal portion of the dentogingival plexus remain dilated. Moreover, the numbers of functioning vessels increase as a result of vascular proliferation and opening of previously inactive vascular units. With additional plaque accumulation, there is a more pronounced infiltration of neutrophils and monocytes (macrophages) in the dentogingival epithelium when compared to the initial lesion. The inflammatory cell infiltrate in the connective tissue at this stage contains small and medium-sized lymphocytes. Many of these are T cells responsible for cell-mediated immune reactions, while others represent B cells which will probably develop into antibody-producing plasma cells. Some fibroblasts within the inflammatory cell infiltrate exhibit signs of degeneration (cellular vacuolization); presumably some of these cells have been injured by cytotoxic products originating primarily from lymphoid cells (Schroeder & Page 1972).
Towards the end of the 2nd week of abstinence from tooth cleaning, microbial plaque can frequently be found in a subgingival position. The size of the inflammatory cell infiltrate in the connective tissue has increased to occupy approximately 10-15% of the connective tissue volume of the free gingiva. Furthermore, the basal cells of the junctional/sulcus epithelium have proliferated and rete pegs can be seen piercing and entering the coronal part of the infiltrate thus the beginning formation of a periodontal pocket.
The established gingival lesion
This phase of lesion development is commonly referred to as "chronic gingivitis". With continued exposure to plaque, the amount of fluid exuding from the vasculature and the number of leukocytes migrating into the tissues and the gingival crevice increase further. At approximately one month after the onset of plaque accumulation, the cellular as well as the permeability response appear to plateau. It would seem a "steady state" or balance has been achieved and this may last for extended periods of time without the established lesion progressing to the advanced lesion. Large numbers of mature plasma cells are seen in the established lesion and are situated primarily in the coronal connective tissues as well as around vessels in more distant parts of the gingival connective tissues. Collagen continues to be lost in both lateral and apical directions as the inflammatory cell infiltrate expands, resulting in collagen-depleted (ICT) areas radiating deeper into the tissue. Proliferation of the dentogingival epithelium is maintained and fete pegs extend into the connective tissue infiltrate. The dentogingival epithelium adjacent to the ICT is
now commonly referred to as pocket epithelium and forms the external boundary of the inflammatory cell infiltrate. The pocket epithelium is not attached to the tooth surface and is heavily infiltrated with neutrophils and macrophages, as well as lymphocytes and plasma cells. Most of the neutrophils eventually migrate across the epithelium into the gingival pocket. The pocket epithelium may be extremely thin and may actually be ulcerated in some areas. When compared to the junctional epithelium, the pocket epithelium is more fragile and permeable to the passage of substances into and out of the underlying tissues.
The advanced gingival/periodontal lesion
As plaque continues its apical downgrowth along the crown and the cementurn of the root surface, there is a concomitant deepening of the periodontal pocket. This is accompanied by the proliferation of the dentogingival epithelium over the "detached" root surface. The inflammatory cell infiltrate extends laterally and further apically into the connective tissues. Plasma cells (most of which produce IgG antibodies) dominate in the lesions, but lymphocytes, macrophages and neutrophils are also present. At this time the first indication of alveolar bone destruction can be observed histologically and appears to be primarily the consequence of osteoclastic activity. The mechanisms which account for osteoclast stimulation are not completely understood, but plaque as well as host-derived mediators are probably involved.
Textbook of Clinical Periodontology 2nd Ed. Lindhe, pp. 162-168
194. All of the following are true concerning the "Modified Widman" flap technique except:
utilizes a perioosteal releasing incision to develop the flap.
results in a long junctional epithelium
is an esthetic surgical procedure
incorporates osseous corrections
involves 3 incisions; crestal sulcular and horizontal.
The original modified Widman procedure involves osseous correction but Ramfjord's modified approach does NOT meet the original Widman flap Objectives.
It is esthetic in that it does not result in as much recession and loss of papilla as conventional osseous procedures.
The healing is by a long junctional epithelium.
The 3 incisions are 1. Crestal this is 1 mm from the tooth and parrell to the long axis of the tooth. 2. Intrasulcular incision to the depth of the pocket. 3. The horizontal incision is made at 909 degrees to the tooth and removes the remaining tissue.
References. Linde, Textbook of Clinical Periodontology 1989 Pg. 407-410.
195. The microbial composition of newly formed plaque consists primarily of
1. gram positive cocci
2. gram negative cocci
3. gram negative rods
4. spirochetes and rods
The first bugs to colonize the plaque are gram positive cocci. As the plaque matures the gram negatives take over and the nasty spirochetes wheedle the way in. Reference Periodontal Diseases Pg. 156.
196. Which of the following is NOT routinely performed during initial preparation?
1. thorough scaling and root planing
2. definitive occlusal adjustment
3. extraction of hopeless teeth
4. removal of amalgam overhangs
5. replacement of missing teeth
Components of initial therapy according to this reference are scaling and root planing, plaque control, gingival curettage, reduction of iatrogenic irritants, tooth movement, and revaluation. It also states a good case can be made for a presurgical occlusal adjustment to remove gross interference's however the final adjustment is completed after any surgical therapy. Teeth frequently shift position after surgery so the definitive treatment must wait. Reference. Periodontal Diseases Pg. 331-339.
197. An amalgam overhang is:
a primary etiological factor
a secondary etiological factor
only important in causing focal argyrosis
a combination of primary and secondary etiological factors
Carranza, FA Jr., Glickman’s clinical periodondology. 7th edition. W.B.Saunders Co., 1990;403
Overhanging margins provide ideal locations for accumulation of plaque and result in a change in the ecologic balance of the gingival sulcus area favoring the growth of disease-associated organisms (gram-negative anaerobic species) at the expense of the health-associated organisms (gram-positive facultative species.
Linde, J., Textbook of clinical periodontology. 2nd edition; 1989;Munksgaard, Copenhagen: 361.
“...the presence of a subgingival overhanging defective margin may be the only important clinically significant feathure of an amalgam restoration related to the pathogensis of chronic inflammatory periodontal disease”. It is not the overhang of the restoration per se, however, which causes or maintains periodontal disease.
198. Tetracycline is the drug of choice in periodontal disease primarily because:
it is bacteriocidal
it is bacteriostatic
it concentrates in the gingival sulcus
it concentrates in the osseous tissue
it concentrates in the saliva
Carranza, FA Jr., Glickman’s clinical periodondology. 7th edition. W.B.Saunders Co., 1990;715
Tetracyclines reach a concentration in the gingival sulcus 2 to 10 times that in the blood.
199. Localized juvenile periodontitis is characterized by which of the following?
progresses 3-4 times faster than adult periodontitis
affects lower incisors and first molars with vertical osseous defects
bone loss is inconsistent with the amount of local factors present
a gram negative obligate anaerobic cocci is considered a primary etiologic microorganism
all of the above
AA is facultative gram negative rods.
Carranza, FA Jr., Glickman’s clinical periodondology. 7th edition. W.B.Saunders Co., 1990;298-300.
Clinical findings: The most striking feature of early juvenile periodontitis is the lack of clinical inflammation in the presence of deep periodontal pockets.
Radiographic findings: vertical loss of alveolar bone around the first molars and incisors in otherwise healthy teen-agers.
Clinical Course: rate of bone loss is about three to four times faster then that in typical periodontitis.
Bacteriology. ...flora consists mainly of gram-negative anaerobic rods, along with a minimal amount of attach plaque with a larger unattached component. ... two of the facultative bacteria found - Actinobacillus Actinomycetemcomitans and capnocytophaga.
200. Several factors predispose diabetics to periodontitis. Which are correct?
elevated glucose levels in oral fluids can influence microbial flora
impaired erythrocyte function, including phagocytosis may reduce resistance to periodontitis
altered collagen metabolites and vascular changes including stasis
impaired chemotactic and phagocytic activity of polymorphonuclear leukocytes
all of the above
Linde, J., Textbook of clinical periodontology. 2nd edition; 1989;Munksgaard, Copenhagen: 285.
Data indicate that altered neutrophil function may be responsible for accelerated periodontal tissue breakdown in poorly controlled diabetics. An impaired chemotactic and phogocytic activity of the polymorphonuclear leukocytes has been found in diabetics.
Carranza, FA Jr., Glickman’s clinical periodondology. 7th edition. W.B.Saunders Co., 1990;450.
...salivary glucose levels (1 hour after breakfast) were higher in diabetics,...
...PMN leukocyte deficiencies resulting impaired chemotaxis, defective phagocytosis, or impaired adherence.
FSBGD WRITTEN BOARD QUESTION STUDY GUIDE 2000
According to the July 1997 American Heart Association recommendations, which of the following require antibiotic prophylaxis for invasive dental treatment?
Organic heart murmur with regurgitation
Isolated secundum atrial septal defect
Previous history of endocarditis
Most artificial joint patients
Endocarditis prophylaxis is not recommended for: (1) isolated secundum atrial septal defect; (2) surgical repair of atrial septal defect; ventricular septal defect, or patent ductus arteriosus (without residua beyond 6 months); (3) previous coronary artery bypass graft surgery; (4) mitral valve prolapse without valvar regurgitation; (5) physiologic, functional, or innocent heart murmurs; (6) previous Kawasaki disease without valvar dysfunction; (7) previous rheumatic fever without valvar dysfunction; and (8) cardiac pacemakers (intravascular and epicardial) and implanted defibrillators.
JADA, Vol, 128, August 1997. pp 1142-1151.
An expert panel of dentists, orthopaedic surgeons, and infectious disease specialists, performed a thorough review of all available data to determine the need for antibiotic prophylaxis to prevent hamatogenous prosthetic joint infections in dental patients who have undergone total joint arthroplasties. The result is a report adopted by both organizations as an advisory statement. Conclusion: Antibiotic prophylaxis is not indicated for dental patients with pins, plates and screws, nor is it routinely indicated for most dental patients with total joint replacements.
Patients at potential increased risk of hematogenous total joint infection include: Immunocompromsied / immunosuppressed patients such as (a) patients with disease-, drug-, or radiation-induced immunosuppression; (b) patients with inflammatory arthropathies such as rheumatoid arthritis and systemic lupus erythematosus. Other patients at increased risk include (a) type I diabetics; (b) patients with previous prosthetic joint infections; (c) malnourished patients; and (d) hemophilic patients.
JADA, Vol. 128, July 1997. pp 1004-1008.
The correct answer is: A. 1,4
2. Which of the following groups of drugs has the greatest potential for diverse side effects when they are being administered to a patient undergoing local anesthesia with a vasoconstrictor?
mono-amine oxidase inhibitors
Although the potential for interactions involving local anesthetics is great, clinical manifestations appear infrequently and only when very large doses are used or when unusual patient factors are present. Much more likely to occur are interactions between various drugs and the vasoconstrictors employed during local anesthesia. Despite statements to the contrary, local anesthetics containing epinephrine may be used without special reservation in patients taking monoamine oxidase inhibitors..Of the vasoconstrictors currently added to local anesthetic solutions, phenylephrine is contraindicated with concomitant MAO therapy.
Vasoconstrictor- added to slow the absorption of the local anesthetic. This results in (a) increased depth and duration of anesthesia, (b) reduced toxicity of the local anesthesia, and (c) improved hemostasis at local site. Epinephrine, in concentrations of 4 to 20 ug/ml (1:250,000 to 1:50,000) is the most frequently employed agent, but levonordefrin, norepinephrine, and phenylephrine are also used.
Pharmacology and therapeutics for dentistry, Neidle, Kroegerand Yagiela 1980, pp 263-283.
The following paper discusses vasoconstrictors and drug interaction. The author rates each drug interaction from 1-(major problem established )to 5-(minor or unlikely). The following all have ratings of 1.
Tricyclic Antidepressants – May modify cardiovascular response to vasoconstrictors.
B-Adrenergic Antagonists – May cause bradycardia leading to cardiac arrest.
General Anesthetics – Enhances the dysrhythmogenic potential of adrenergic drugs.
Cocaine – Prevents active re-uptake of norepinephrine therefore potentiates the effect of adrenergic vasoconstrictors.
Yagiela HA Adverse drug interactions in dental practices: interactions associated with vasoconstrictors (Part V). JADA, 130:701-709, 1999.
Considering all of the potential adverse reactions of epinephrine use, it is essential that the clinician make every effort to minimize epinephrine administration, obtain an adequate medical history, and minimize stress. The maximum recommended dose of epinephrine for a healthy adult is 0.2 milligrams, while for the patient with cardiovascular disease, it is 0.04 milligrams. In cases where the use of a vasoconstrictor is absolutely contraindicated (hyperthyroidism and pheochromocytoma), and agent such as 3% mepivacaine without a vasoconstrictor should be used.
The correct answer is C.
3. A patient presents with fractures of the maxillae, orbits and ethmoid bones. This midface trauma can be classified as:
The LeFort I fracture frequently results from the application of horizontal force to the maxilla, which separates the maxilla from the pterygoid plates and nasal and zygomatic structures. This type of trauma may separate the maxilla in one piece from other structures, split the palate, or fragment the maxilla. Forces that are applied in a more superior direction frequently result in LeFort II fractures, which is the separation of the maxilla and the attached nasal complex from the orbital and zygomatic structure. A LeFort III fracture results when horizontal forces are applied at a level superior enough to separate the naso-orbital ethmoid complex, the zygomas, and the maxilla from the cranial base, which results in a so-called craniofacial separation.
Peterson, L.J., et al, Contemporary Oral and Maxillofacial Surgery, 1998, Mosby
A horizontal fracture (LeFort I) is one in which the body of the maxilla is separated from the base of the skull above the level of the palate and below the attachment of the zygomatic process. It results in a freely movable upper jaw. The pyramidal fracture (LeFort II) is one that has vertical fractures through the facial aspects of the maxillae and extends upward to the nasal and ethmoid bones. It usually extends through the maxillary antra. One malar bone may be involved.
Kruger, G.O., Textbook of Oral and Maxillofacial Surgery, 1984, Mosby
The correct answer is e. Leforte 3.
4. Traumatic tattoos can be minimized or corrected by all of the following except:
Use of high pressure lavage
Minimal use of saline irrigation
Use of a dermabrader
Use of soap and water and vigorous scrubbing
Removal of oily substances by acetone
Abrasions are often produced by trauma that allows dirt, cinders, or other debris to be ground into the tissue. If allowed to remain in the wound, a traumatic tattoo will result. These particles should be removed by mechanical cleansing. They should be cleansed with one of the detergent soaps and then isolated with sterile towels. A local anesthetic is then injected and the involved area is meticuloulsy scrubbed with a detergent soap on sterile gauze. Frequent irrigation of the field with sterile saline solution aids in washing the particles form the wound. The use of an electric dermabrader for the removal of large areas of imbedded particles has been recommended. The procedure is tedious and time consuming, but removal of these particles is extremely important.
The correct answer is E.
Kruger, G.O., Textbook of Oral and Maxillofacial Surgery, 1984, Mosby
5. A shift to the left in the patient’s WBC means a _____ in the number of ________.
increase; immature neutrophils
decrease; immature leucocytes
increase; mature leucocytes
Adult/child>2 years: 5000-10,000/mm 3 or 5-10.0 x 109 /L (SI units)
Neutrophils: 55% to 70%
Lymphocytes: 20% to 40%
Monocytes: 2% to 8%
Eosinophils: 1% to 4%
Basophils: 0.5% to 1.0%
The WBC count has two components. One is a count of the total number of WBCs (leukocytes) in 1 mm 3 of peripheral venous blood. The other component, the differential count, measures the percentage of each type of leukocyte present in the same specimen. An increase in the percentage of one type of leukocyte means a decrease in the percentage of another. Neutrophils and lymphocytes make up 75% to 90% of the total leukocytes. These leukocyte types may be identified easily by their morphology on a venous blood smear. The total leukocyte count has a wide range of normal values, but many diseases may induce abnormal values. An increased total WBC count (leukocytosis) usually indicates infection, inflammation, tissue necrosis, or leukemic neoplasia. Trauma or stress, either emotional or physical, may increase the WBC count. Leukopenia (i.e., a decreased WBC count) occurs in many forms of bone marrow failure (e.g., following antineoplastic chemotherapy or radiation therapy, marrow infiltrative diseases, overwhelming infections, dietary deficiencies, and autoimmune diseases). The major function of the WBC’s is to fight infection and react against foreign bodies or tissues. Five types of WBC’s may easily be identified on a routine blood smear. These cells, in order of frequency, include neutrophils, lymphocytes, monocytes, cosinophils, and basophilsl. All these WBC’s arise from the same “pluripotent” stem cell within the bone marrow as the red blood cell (RBC) does. Beyond this origin, however, each cell line differentiates separately. Most mature WBC’s are then deposited into the circulating blood.
Polymorphonuclear neutrophils are produced in 7 to 14 days and exist in the circulation for only 6 hours. The primary function of the neutrophil is phagocytosis (killing and digestion of bacterial microorganisms). Acute bacterial infections and trauma stimulate neutrophil production, resulting in an increased WBC count. Often, when neutrophil production is stimulated, early immature forms of neutrophils enter the circulation. These immature forms are called band or stab cells. This process, referred to as a “shift to the left” in WBC production, is indicative of an ongoing acute bacterial infection.
Lymphocytes are divided into two types: T cells and B cells. T cells are primarily involved with cellular-type immune reactions, whereas B cells participate in humoral immunity (antibody production). The primary function of the lymphocytes is fighting chronic bacterial infection and acute viral infections. The differential count does not separate the T and B cells but rather counts the combination of the two
Monocytes are phagocytic cells capable of fighting bacteria in a way very similar to that of the neutrophil. Monocytes can be produced more rapidly, however, and can spend a longer time in the circulation than the neutrophils.
Basophils, and especially eosinophils, are involved in the allergic reaction. Parasitic infestations also are capable of stimulating the production of these cells.
6. A patient is
taking coumadin. Which blood study do you use to
determine his status for surgery?
WBC and differential
Both b and c
a. WBC and differential -
White Blood Cell Count - normal - 4,500 - 11,000 /mm3
Leukocyctosis is > 11,000/mm3
Differential WBC Count - Estimation of percentage of each cell type/mm3
Normal - neutrophils 50-60% lymphocytes 20-30% monocytes 3-7%
eosinophils 3% basophils <1%
b. Platelet count -may have adequate number of platelets, but they may be
nonfunctional due to aspirin or motrin use. Bleeding time will reflect
problems with both the number and quallity of platelets.
Normal value - 140,000 to 400,000 platelets/mm3
Bleedings Problems - < 50,000 platelets/mm3
c. PT - PT test is often used by physicians to monitor anticoagulant
therapy i.e. coumadin. Coumarin is a Vit K antagonist (Vitamin K is
necessary for the final activation of factors II, VII, IX and X),
interferes with fibrin formation and is used to prevent thrombus
development and extension. Coumadin is used to treat peripheral thrombi,
pulmonary embolism, valvular heart disease (prosthetic heart valves),
acute myocardial infarction, and dysrhythmias
The ADA recommendation is that the level of anticoagulation be 1.5-2.0
times the normal PT before a surgical procedure is attempted. Little to
no risk of significant bleeding is noted at these levels.
International Normalized Ratio (INR) is the new American Heart
Association classification system for the PT time. The INR allows
comparison from one hospital to another. The calculation involves the
Patient's PT/Normal PT. Normal INR is 3-3. (ref: Little JW Falace DA.
Dental Management of the Medically Compromised Patient, 1997)
d. PTT - PTT test is often used by physicians to monitor heparin therapy
e. Both b and c
Additionally: two major pathways for hemostasis: Extrinsic and
PET vs PITT PET = PT + E for Extrinsic PITT = PTT + I for
PT monitors Extrinsic pathway normal value 11-15 seconds
PTT monitors Intrinsic pathway normal value 25-40 seconds
In an alveoplasty involving the anterior maxillary segment, prior to insertion of an immediate denture, the dentist should:
retain the labial frenum to assure peripheral seal.
Remove only enough bone to allow for insertion of the denture.
Retain the canine eminences to control the position of the buccl flange of the denture base.
Remove all undercuts to avoid potential sore spots.
Ensure the denture places firm pressure to all extraction sites to stop the bleeding.
(B) In an alveoloplasty involving the anterior maxillary segment, prior to insertion of an immediate denture, the dentist should remove only enough bone to allow for insertion of the denture. Only the protuberances that prevent insertion of the denture or retard healing are removed. Conservatism should be the paramount guide. Wide retraction of tissues increases bony resorption and obliterates sulci. Labial, lingual, and palatal sharp edges should be reduced to provide a U-shaped ridge. Bone should not be sacrificed for primary tissue closure. Inflamed or excessive interdental and interradicular tissue should be trimmed and removed. Exceptions to this are the following:
Correction of severe overbite and overjet.
Patients with oral cancer who are to undergo radiation therapy.
Which of the following are correct regarding the placement of dental implants?
1. it is desirable for the implant to reach the inferior cortex of the mandible for
with low mandibular height, the inferior cortical bone may be intentionally
sites of failed implants can be revised for another fixture after one year.
osseointegration occurs more rapidly in the maxilla than in the mandible due to better blood supply.
recommended waiting at least 4 months in the mandible and 6 months in the maxilla prior to beginning stage two.
all of the above
Answer: (D): I feel #1,2,3,5 are correct statements with #4 being an incorrect statement. You may try to utilize the inferior cortex for stabilization if presented with Lekholm and Zarb type IV bone which would have poor initial stabilization and in cases where inadequate vertical height of bone is present in the anterior mandible. Type IV bone has the highest failure rate (35% of all failures, Jaffen and Berman, J Perio 1991). Intentional perforation of the cortical plate may be done in a patient with a severely resorbed anterior mandible. A transosseous or staple implant developed by Small in the 1970’s places a plate on the inferior border of the mandible with pins extending through bone to penetrate the alveolar mucosa. This system is usually used to support an overdenture, requires >9 mm vertical and >5 mm width of bone and is designed as a functional implant for atrophic edentulous mandible (4 mm height). Sites of failed implants should be treated like a delayed placement type of treatment plan (wait 9 months or longer) to gain the advantage of bone fill for initial stabilization, if the dimensions of bone do not allow for placement of a larger fixture. If the bone dimensions allow for a larger fixture after initial failure, the time may be much sooner. Osseointegration occurs more rapidly in the anterior mandible (3-4 months), posterior mandible (6 months) and then in the maxilla (6-9 months) in the anterior and posterior regions. The healing time is influenced by the quality of existing bone (Lekholm and Zarb Type I homogeneous compact bone is best) and this denser cortex with coarser, thicker cancelli is usually found in the anterior mandible. Bone in more posterior locations of both jaws tends to have thinner, more porous cortex and finer cancelli. Also, the bone cells per unit volume is much greater in the mandible.
While extracting a mandibular third molar, it is noted that the tip of the distal root is missing. The root tip is most likely in the
inferior alveolar canal
Fractured mandibular molar roots may be displaced through the thin linguocortical plate and into the submandibular space. The answer is c.
The maximum dosage of epinephrine / levonordefrin that should be administered to a patient with a cardiac condition during any one dental procedure is _____ mg / _____ mg.
.018 / 0.40
0.04 / 0.20
0.20 / 0.50
0.04 / 0.40
0.02 / 0.04
A normal healthy patient can receive 0.2 mg of epinephrine per appointment (20 ml of a 1:100K concentration or 10 carpules). A patient with clinically significant cardiovascular impairment should be limited to 0.04 mg per appointment (4 ml of 1:100K or 2 carpules). This narrows the answer to b and d. For levonordefrin, the maximum dosage should be 1.0 mg for all patients (20 ml of a 1:20K concentration or 10 carpules), regardless of cardiovascular status. For patients taking cardiac glycosides (digoxin), however, the maximum is 0.2 mg of Neo-Cobefrin. Therefore, since 1 mg is not listed for levonordefrin, answer b is the best answer.
All of the following are found in the cavernous sinus except:
Internal Carotid Artery
I cannot find anything in Netter, Petersen, or our notes that shows either CN I or VIII to be in the cavernous sinus. The answer is a or d.
The safest drugs to administer during pregnancy are:
Aspirin, phenacetin, valium, lidocaine
Acetaminophin, codiene, erythromycin, lidocaine
Aspirin, tetracycline, codiene, mepivicaine
Acetaminophen, codiene, streptomycin, mepivicaine
Ibuprophen, codeine, penicillin, lidocaine
The FDA has established pregnancy categories for drugs according to their potential to cause fetal injury. Briefly, they are:
A = No risk demonstrated to the fetus in any trimester.
B = No adverse effects in animals.
C = Adverse reactions in animals. Risk to the fetus must be considered.
D = Definite fetal risk. Avoid if possible.
X = Fetal abnormalities. Do not use during pregnancy.
Assessing the analgesics listed first:
Not established. Use not recommended.
Which leads to answer b and d as the safest choices. Codeine has demonstrated safety and efficacy in all trimesters of pregnancy. Assessing the antibiotics,
Lidocaine has not been associated with any adverse effects. The minimum amount of anesthetic should be administered and the use of a vasoconstrictor minimized.
Therefore, the best answer is b. The bottom line: You never mention ibuprophen or tetracycline in the same sentence with pregnancy.
13. The following are true about osteomyelitis except:
It starts in the medullary cavity, then extends to cortical bone, then to periosteum.
Inflammation and edema compromise blood supply so that normal defense mechanisms don’t reach the area.
Symptoms include deep severe pain, tenderness and swelling.
Treatment includes hospitalization, surgical removal of infected bone and long-term (10 days) of IV antibiotics.
There are both suppurative and non-suppurative types of osteomyelitis.
The correct answer is e. Osteomyelitis is classified into two major types, acute suppurative osteomyelitis and chronic suppurative osteomyelitis.
Osteomyelitis means “inflammation of the bone marrow.” It usually begins in the medullary cavity and then extends and spread to the cortical bone and eventually to the periosteum. Acute suppurative osteomyelitis shows little or no radiographic change-10 to 12 days are required for lost bone to be detected radiographically. Treatment of choice is Penicillin due to effectiveness against streptococci and anaerobes. Second choice is Clindamycin. Chronic suppurative osteomyelitis has a “moth eaten” appearance of affected bone. Requires aggressive surgical therapy- admitted to the hospital and given IV antibiotics. Therapy of both should ensure that antibiotics are continued for a much longer time than is usual. Peterson Oral Surgery446-447. 426-428 1998.
14. Paresthesia following fractures is most commonly seen in
Fractured neck of the condyle
Fractured symphysis of the mandible
Zygomaticomaxillary complex fracture
Displaced fracture of the coronoid process
Fractures at angle of the mandible
The correct answer is c. Zygomaticomaxillary complex fracture.
Zygomaticomaxillary complex fracture shows a step in the dental arch. A symptom present in the majority of mid-facial fractures is impairment of sensation of the infra-orbital nerve in 94.2 of lateral mid-facial fractures. Pg. 116-117. Kruger Vol 2 Oral and Maxillofacial Traumatology 1986.
15. In a lip laceration, list in descending order of importance the structures or layers that must be approximated:
Mucosa, muscle layers, lip philtrum, vermillion border, skin
Skin, lip philtrum, vermilion border,muscle layers, mucosa
Vermilion border, lip philtrum, muscle layers, mucosa, skin
Lip philtrum, vermilion border, muscle layers, mucosa, skin
Vermilion border, skin, lip philtrum, muscle layers mucosa
C. Vermilion border,lip philtrum, muscle layers, mucosa, skin
First suture is placed at mucocutaneous junction- extremely important to realign this or cosmetic deformity may result. Lip is then closed in three layers: oral mucosa, muscle and dermal surface. 583- 586 Peterson 1998, pg. 124 handout for O.S.
What is the best radiograph to view the subcondylar neck area?
A-P view of the skull
Modified Towne’s view
A-P view of the skull (orbital rim, frontal, ethmoid sinuses, nasal septum)
Lateral oblique (mandibular body and ramus)
Modified Towne’s view (condylar neck fractures)
Water’s view (best for viewing facial fractures)
Submental vertex (fractures of zygomatic arch) Peterson 592-593 1998.
17. Cutting the motor root of the Trigeminal nerve (V) would affect which of the following:
muscles of mastication, tensor veli palatini and levator veli palatini
tensor tympani, tensor veli palatini and levator veli palatini
muscles of mastication, anterior belly of digastric, tensor tympani and tensor veli palatini
muscles of mastication, posterior belly of the digastric and anterior belly of the digastric
muscles of mastication, extrinsic muscles of the tongue and tensor tympani
The correct answer is C
The mandibular nerve (V3) has a sensory root and a motor root (it’s the only branch of the Trigeminal nerve with voluntary motor fibers). These motor fibers distribute to the muscles of mastication, mylohyoid, anterior belly of the digastric, tensor veli palatini and tensor tympani.
Ref: Textbook of anatomy, 4th ed., Hollinshead & Rosse, 1985.
18. Which of the following best describes the retrodiscal tissues referred to as the bilaminar zone of the TMJ?
elastic and fibrous tissue that is highly innervated by the auriculotemporal nerve
a thin ligamentous structure that is reinforced laterally by the temporomandibular ligament
avascular hyaline cartilage
vascular, highly innervated fibrocartilage
fibrous connective tissue innervated by the temporal nerve
The correct answer is A
Ref: Okeson JP. Management of Tempormandibular Disorders and Occlusion, 4th ed., 1998 (pages 9-11 & 13).
Topographical anatomy notes (pages 2-5)
19. A small accidental opening into the maxillary sinus results from removal of a maxillary first molar, but the sinus membrane shows no perf. The preferred initial treatment is to:
elevate a buccal sliding flap and cover the entire extraction site
rotate a pedicle flap from the palate over the socket and suture tightly with nonresorbable sutures
have the patient perform the valsalva maneuver to see if bubbles can be seen in the socket
pack the socket with antibiotic-saturated iodoform gauze
perform routine postoperative care to assure the formation of and organization of a clot
The correct answer is E
When exposure and perforation of the antrum result, the least invasive therapy is indicated. If the opening is small, efforts should be made to establish a good blood clot in the extraction site and preserve it in place. The patient can be instructed to use nasal precautions for 10-14 days (open mouth when sneezing, no straw sucking and avoiding nose blowing). The patient is also placed on a 7-10 day regimen of antibiotics, an antihistamine and a systemic decongestant. See patient at 48-72 hour intervals.
Ref: Contemporary Oral and Maxillofacial Surgery, 2nd ed., Peterson, Ellis, Hupp & Tucker, 1993 (p.476).
20. A patient with a full complement of teeth presents with a non-displaced fracture through the body of the mandible. Treatment of choice is:
Kirshner wire insertion
Closed reduction with intermaxillary wiring
If favorable, no fixation required
The correct answer is D
Treatment of a fracture consists of reduction and fixation accomplished together in one stage. Applying wires or elastic bands between the upper and lower jaws to which suitable anchoring devices have been attached does this. This will successfully treat most fractures of the mand. The main method of such fixation is wiring, arch bars and splints.
Ref: Textbook of Oral and Maxillofacial Surgery, Kruger (pages 374, 385-393)
21. What is the most common indication for removal of third molars? Answer is D
Damage to adjacent teeth
Destruction of bone on 2nd molars
Associated cysts and tumors
NIH criteria are: Pericoronitis
Distal caries in adjacent tooth
Resorption of 2nd or 3rd molars
Beeman CS 3rd molar management J. oral Maxillofac Surg. 57:1999 824-830.
Penicillin is still the antibiotic of choice for oral infections, however, other Beta lactams may be the best in all of the following situations except: Answer is D
Development of resistant organisms
Cultures confirm that infection is from mixed aerobes and anaerobes
Need for increased gram negative organism coverage
Need for greater activity against anaerobes
Patient is immunocompromised
Saunders text states: Greater than 90% of infections are aerobic strep, anaerobic strep, pepto strep, prevotella and fusobacteria. Metronidazole is affective only against anaerobic and reservecd for sutuations where only anaerobes are suspected. Page 405.
A patient has sustained bilateral fractures in the region of the mandiblular condylar necks. There are no other injuries. Clinical signs will include: Answer is A
Inability to protrude the mandible
Inability to contact the molar teeth
Anterior closed bite
Gross unilateral deviation of the mandible on excursion attempts
mental nerve anesthesia
Ludwig’s Angina is: Answer is D
An abscess involving the sublingual, submental and submandibular spaces
An abscess inpinging on the lateral pharyngeal space
Cellulitis involving the space of the body of the mandible
Cellulitis involving the sublingual, submental, and submeandibular spaces
Cellulitis involving the retropharyngeal space
Saunders text: page 423 calls it a “Rapidly spreading cellulitis. Characterixed by trismus, drooling, difficulty swallowing. Usually streptococci. Hospiitalize, I&D, antibiotics and watch the airway.
CHARACTER CELLULITIS ABSCESS
Severe & Generalized
Degree of Seriousness
When a tuberosity is fractured during surgery, all of the following are correct except: Answer is A
Lay a full thickness flap, secure tuberosity with wires, let heal 2-3 months, then remove tooth.
If attached to periosteum, dissect away from tooth, remove tooth, then secure with sutures
If tuberosity is very mobile, splint tooth and let heal 6-8 weeks, then extract with an open surgical technique
If detached from soft tissue, remove, smooth edges, suture to cover defect.
Goal is to maintain the fractured bone in place and to provide the best possible environment for healing. Based on reading, anything that disrupts the blood supply to the bone is BAD. Blood is GOOD. B and C were specifically mentioned in text. D was alluded to as acceptable, but would likely leave a defect impacting complete dentures. A was not mentioned but is reasoned as bad because the blood supply is from the periosteum.
26. An 8-year old male presents with an expansile, multi-locular radiolucency involving the posterior mandible and associated with impacted #30. The lesion is biopsied and the pathologist’s report describes multinucleated giant cells and dilated vascular spaces. The most likely diagnosis would be:
ameloblastic fibroma (mixed tumor, posterior mandible, 40% under age 10, strands of epithelial cells and connective tissue)
odontogenic keratocyst ( rare in people under 10 years, uniform epithelium (palisaded), parakeratin)
aneurysmal bone cyst (age <20, ♀=♂, hrx of trauma, multinucleated giant cells, dilated vascular spaces)
dentigerous cyst (association with crown of un-erupted tooth, epithelium lined cyst)
ameloblastoma (age 20-40, ♀=♂, 80% in mandible, polyhedral cells, palisaded nuclei)
Shafer, Hine & Levy A Textbook of Oral Pathology
All of the following have well documented adverse interactions with epinephrine:
1. Non-selective beta-blockers (risk tachycardia, discouraged not contraindicated)
2. Tricyclic anti depressants (potential arrythmias, contraindicated)
3. MAO inhibitors (risk hypertensive crisis, not considered contraindicated by this author,)
4. Cocaine (same sight of action as catacholamines, potential overload of system)
5.Calcium Channel blockers (Potential risk of increased hypertensive affect, not contraindicated)
2,3,4, (although MAOI is not an absolute contraindication it has strong warnings)
Goulet, Perusse & Turcotte Contraindications to vasoconstrictors in dentistry: Part III OOO (74), 692-697
28. Which of the following types of hepatitis is most likely to be contracted through a blood transfusion?
Hepatitis A (oral-fecal)
Hepatitis B ( percutaneus)
Hepatitis C ((percutaneous) although now screened for transmission is .1%)
Hepatitis D (must have Hep B to contract)
Hepatitis E (oral-fecal)
Gillcrist, Hepatitis Viruses A,B,C,D,E &G Implications for Dental Personnel 1999 JADA (130) 509-520
radiographs may show a stepladder trabecular pattern (True)
Nitrous oxide use in the treatment of patients is contraindicated (greater than 50% N20).(True)
A crisis may be precipitated by odontogenic infections.(True)
Prophylactic antibiotic coverage is indicated for routine procedures.(only for surgical procedures)
The oral mucosa appears hemmorrhagic and early eruption patterns are often seen (delayed eruption , dental hypoplasia)
Little & Falace Dental Management of the Medically Compromised Patient
The vast majority of salivary calculi are found in the duct of which of the following glands?
minor salivary glands
equally in a and c
A sialolith is a salivary stone formed in the salivary ducts, usually from a disturbance in the patient’s calcium balance or dehydration. According to the handout from the Oral Pathology Course, given by CDR Shaffer, the submandibular gland is the primary site of sialoliths. In the submandibular gland, the salivary calcifications are generally found in Wharton’s Duct. Bartholins Duct and Rivinus Ducts are found in the sublingual gland and Stenson’s Duct is found in the parotid gland. Treatment involves …
31. Examples of Type III allergic hypersensitivity reactions are:
extrinsic bronchial asthma
systemic arthus reaction
1, 3, 6
2, 5, 7
2, 4, 5
3, 4, 7
1, 4, 6
There are two general types of allergic reactions; immediate and delayed, according to Shafer, Hine, and Levy or Sonis, Fazio, and Fang). Immediate reactions involve circulating antibodies in the serum of allergic patients and include; anaphylaxis, hay fever, asthma, serum sickness, angioneurotic edema, and wheal-and-erythema skin reaction. Delayed reactions do not generally involve circulating antibodies and include; drug allergies, allergies of certain infections, and contact reactions to a variety of materials. Based on these categories, an answer is impossible.
But, hold everything! According to the Merck Manual, “With the present stage of knowledge it is difficult to classify the gamut of diseases in which hypersensitivity phenomena play a role.” The Gell and Coombs classification is one of many that has proved to be clinically and conceptually helpful and is widely used. In this classification system, there are four categories, Types I, II, II, and IV. Merck continues, “It should be emphasized that in order to be classed as a hypersensitivity reaction a pathologic process must be the result of a specific interaction between antigen (exogenous or endogenous) and either humoral antibodies or sensitized lymphocytes. This classification system, therefore, excludes those diseases in which antibodies are demonstrated, but have no known pathophysiologic significance, even though their presence may have diagnostic value.”
Type I: Immediate-Type, Atopic, Reaginic, Anaphylactic, or IgE-Mediated Hypersensitivity Reactions.
Type II: Cytotoxic Reactions, Cytolytic Complement-Dependent Cytotoxicity, Cell-Stimulating Reactions.
Type III: Immune Complex or Soluble Complex Hypersensitivity Reactions, Toxic Complex Reactions.
Type IV: Cellular, Cell-Mediated, Delayed, or Tuberculin-Type Hypersensitivity Reactions.
Therefore, I find the following, though I find difficulty in understanding the material. Maybe CAPT Mitchell’s Immunology Course will shed light on the subject.
1. Contact dermatitis – Type IV
2. Serum sickness – Type III
3. Extrinsic bronchial Asthma - Type I
4. Allergic rhinitis - Type I
5. Systemic arthus reaction – Type III
6. Tuberculosis- Type IV
7. Lupus erthematosus – Type III
The answer is#2, #5, and #7, or b.
The International Normalized Ratio (INR) is a value that would be reported for which of the following lab tests:
Prothrombin Time (PT)
Partial Thromboplastin Time (PTT)
None of the above
The answer is b. The INR is reported with the PT test and is used to evaluate a patient’s clotting ability. It measures the effectiveness of the extrinsic pathway for coagulation. A normal prothrombin time is usually between 11-15 seconds. The value is compared to a control value generated by the laboratory. A prolonged prothrombin time can be associated with abnormal coagulation and resultant bleeding. A PT less than 1.5-2.0 or an INR 2.0-4.0 is considered within normal limits.
A 62 year old woman is referred to you from her family physician because of painful, red, eroded gingiva that has not responded to supplemental vitamins and iron therapy. Your examination reveals several areas of erythematous gingiva, as well as, similar appearing lesions on her soft palate and cheeks. A white film is easily rubbed from the surface of some of the lesions. She has no skin lesions. Your differential diagnosis may include:
erosive lichen planus, hyperkeratosis, candidiasis
desquamative gingivitis (pemphigoid), erosive lichen planus, candidiasis, pemphigus vulgaris
lupus erythematosis, pemphigus vulgaris, angioneurotic edema, actinic keratosis
desquamative gingivitis (pemphigoid), erosive lichen planus, chronic atrophic candidiasis, pemphigus vulgaris
erosive lichen planus, lupus erythematosis, pemphigus vulgaris, candidiasis
Erythematous gingiva is common for many pathologic conditions.
White film that can be rubbed off is indicative of pseudomembranous candidiasis, but not hyperkeratosis. This eliminates a and c.
Skin lesions may follow oral lesions in pemphigus and pemphigoid (ocular or genital) so these can not be ruled out. Lupus is generally associated with skin lesions. This eliminates c and e.
Which leaves b and d which differ in their candidiasis diagnosis only. Chronic Atrophic Candidiasis generally is found under a denture and is not white in color. Since it is not clear of her prosthetic status and the lesions are white, b is the best answer.
Don’t forget Squamous Cell Carcinoma in your differential!
34. An ameloblastoma is most likely to develop from the epithelial lining of which of the following cysts?
c. residual periradicular
d. lateral periodontal
Development of ameloblastoma and mucoepidermoid carcinoma from a dentigerous cyst wall has been reported. Oral Pathology Notes-Odontogenesis and Odontogenic Cysts-06 March 2000.
35. Which of the following are radiographic characteristics of acute osteomyelitis?
Expansion of the cortical plate
Patients with acute osteomyelitis have signs and symptoms of an acute inflammatory process that has been less than 1 month in duration. Fever, leukocytosis, lymphadenopathy, significant sensitivity, and soft tissue swelling of the affected area may be present. Radiographically, you tend to see a diffuse, ill-defined radiolucency. Sequestration or exfoliation of fragments of necrotic bone may be seen. An involucrum is a necrotic piece of bone within viable bone.
Inflammatory Diseases of Bone also include focal sclerosing osteomyelitis, chronic diffuse sclerosing osteomyelitis, chronic osteomyelitis w/proliferative periostitis, and osteoradionecrosis.
Focal sclerosing osteomyelitis (condensing osteitis) is a localized proliferative reaction of bone secondary to a low grade inflammatory stimulus and radiographically presents as a radiopaque are surrounding the root apex with continuity of the PDL and a definitive outline.
Chronic diffuse sclerosing osteomyelitis is a chronic proliferative reaction of bone to a continuous irritant or infection. Radiographic presentation typically presents as a single site within a quadrant but may be multifocal or fill the entire quadrant, is poorly circumscribed and mixed radiolucent-radiopaque lesion. Later on in the process, it becomes a more diffuse sclerosis.
Chronic osteomyelitis with proliferative periostitis or Garre’s osteomyelitis is a focal, nonsuppurative inflammatory process with the periosteum producing excessive bone as a reaction to mild irritation or infection. Radiographically presents as layers of new bone or onion-skin appearance deposited between the cortex and periosteum. Similar onion-skin appearance is found in osteosarcoma and Ewing’s sarcoma.
Osteoradionecrosis is a chronic infection of bone following high dose radiation therapy and characterized by pain, necrosis, and sequestration. Radiographically presents as an ill-defined area of radiolucency that may develop zones of opacity as the bone separates from the residual vital bone.
Reference: Oral and Maxillofacial Pathology, Neville, Damm, Allen, and Bouquot. Pg. 114. And Class notes by CDR Shafer.
Hyperalgesia is used diagnostically in dentistry by use of _____ forces to elicit pain.
Allodynia: Pain due to a stimulus that does not normally provoke pain. Seen commonly in neuropathic pain.
Hyperalgesia: An increased response to a stimulus that is normally painful.
Reference: Clinical management of Temporomandibular disorders and Orofacial Pain, Pertes & Gross, 1995, Pg 319.
Hyperalgesia is defined as excessive sensitivity or sensibility to stimulation. It may be primary or secondary. Primary hyperalgesia results from a local cause that has lowered the pain threshold of the structures that hurt. Secondary hyperalgesia is hyperalgesia without local cause. The pain threshold in the area is essentially normal. Superficial secondary hyperalgesia is felt as excessive sensitivity to touch.
Reference: Temporomandibular Disorders, Classification, Diagnosis, Management, Weldon Bell, 1990, 3rd ed. Pg 138.
Hyperalgesia includes lowering of the threshold for the perception of pain and increased pain from a suprathreshold stimulus, and may occur in both the primary zone of injury (primary hyperalgesia) and the secondary zone that surrounds the primary site (secondary hyperalgesia).
Reference: Temporomandibular Joint and Masticatory Muscle Disorders, Zarb, Carlsson, Sessle & Mohl, 1994, Pg 190.
Primary hyperalgesia occurs when increased sensitivity results because of some local factor. After a few hours the surrounding tissue becomes sensitive to touch. This is primary hyperalgesia because the source of the problem is in the same location as the site of the heightened sensitivity. Secondary hyperalgesia is present when there is increased sensitivity of tissues without a local cause. A common location is the scalp. Patients who experience constant deep pain commonly report that “their hair hurts”. When the scalp is examined, no local cause can be found. Secondary hyperalgesia is slightly different from referred pain in that local anesthetic blocking at the source of the pain may not immediately arrest the symptoms.
Reference: Management of Temporomandibular Disorders and Occlusion, Jeffrey Okeson, 1998, 4th ed., Pg 62, 329.
The most common cause of swollen ankles in the elderly patient is:
Venous valvular incompetence
A high level of protein in the urine
Congestive heart failure (CHF) is the inability of the heart to deliver an adequate supply of oxygenated blood to meet the body’s metabolic demands. CHF affects between two and three million persons in the United States, with about 500,000 new cases diagnosed each year. It is very common in the elderly, representing the most frequent hospital discharge diagnosis in patients over age 65. CHF can involve failure of the left and right ventricle. Most of the acquired disorders that lead to CHF will result in failure of the left ventricle, with right ventricle failure following. In left-sided heart failure, blood backs up from the heart into the lungs. The result is dyspnea (shortness of breath on exertion). orthopnea (shortness of breath when supine), and paroxysmal nocturnal dyspnea (dyspnea awakening the patient from sleep). In right-sided heart failure blood backs up from the heart into the veins and organs supplying blood to the heart. The result is peripheral edema, pedal edema, pitting edema, swelling and congestion of the liver, and ascites (fluid buildup in the abdominal cavity).
Reference: Cardiovascular Disease, congestive heart failure , Pharmacotherapeutics in Clinical Dentistry lecture 08 Nov 99, Oral Diagnosis Dept NPDS, Bethesda MD.
Edema in liver disease and renal disease are discussed in detail in the Text Internal Medicine for Dentistry, Rose & Kaye 2nd ed. 1990, Pg 515-535, 941-949. They describe edema in liver disease as ascites and in renal disease as an inappropriate collection of interstitial fluid. Most patients with renal disease initially show edema in the lower extremities.
38. Clinical signs and symptoms of infective endocarditis include:
fever, chills and night sweats
all of the above
Signs: petechiae, linear hemorrhage (nails), Osler nodes, Janeway lesions, Retinal hemorrhages, Clubbing of fingers, Murmurs and Anemic pallor.
Symptoms(primary): Weakness, Weight loss, fatigue, fever,chills, night sweats, arthralgia and myalagia
Symptoms (secondary, caused by septic emboli): paralysis, chest pain, blindness, hematuria, bone pain, stiffness, neurologic symptoms(confusion, stroke) and psychiatric manifestations.
Ref: Little JW, Falace DA. Dental Management of the Medically Compromised Patient 5th edition Pages 108-111
An asymmetric bandlike widened periodontal ligament space around one or two adjacent teeth is reported to be the earliest radiographic sign of:
Florid osseous dysplasia
The correct answer is A.
With osteosarcomas, the radiographic findings vary from dense sclerosis, to a mixed sclerotic and radiolucent lesion, to an entirely radiolucent process. There is often resorption of the roots of teeth involved by the tumor – this feature is often described as “spiking” resorption. The classic sunburst or sunray appearance caused by osteophytic bone production is present in about 25 percent of jaw osteosarcomas. An important early radiographic change in patients consists of a symmetric widening of the periodontal ligament space around a tooth or several teeth.
Radiographically, florid cemento-osseous dysplasia lesions are highly radiodense and lobular in configuration. These dense lobular areas are often interspersed with less well-defined mixed radiolucent and radiopaque alterations in the radiographic pattern.
The chief radiographic feature of fibrous dysplasia is a fine “ground glass” opacification that results from superimposition of a myriad of poorly calcified bone trabeculae arranged in a disorganized pattern. Lateral skull films in cases with maxillary involvement may show increased density of the base of the skull involving the occiput, sphenoid, roof of the orbit, and frontal bones. This is said to be the most characteristic radiographic feature of fibrous dysplasia of the skull.
In patients with scleroderma, on dental radiographs, diffuse widening of the periodontal ligament space is often present throughout the dentition. The extent of the widening may vary, with some examples being subtle and others quite dramatic. Varying degrees of resorption of the posterior ramus of the mandible, the coronoid process, and the condyle may be detected on panoramic radiographs, affecting approximately 20 percent of patients.
The most typical radiographic feature of an ameloblastoma is that of a multilocular radiolucent lesion. The lesion is often described as having a “soap bubble” appearance when the radiolucent loculations are large and as being “honeycombed” when the loculations are small. Resorption of roots of teeth adjacent to the tumor is common. In many cases, an unerupted tooth, most often a mandibular third molar, is associated with the radiographic defect.
40. The most common location of the Adenomatoid Odontogenic Tumor
Midline of the mandible
The answer is A.
The Adenomatoid Odontogenic Tumor AOT tumor is painless, slow growing usually found in the anterior maxiila (66%). There is a strong female predilection with the average age of 18 yrs. And 75% of lesions occur prior to age 21. Radiographically, there is a unilocular radiolucency with flecks of calcification. It is the only odontogenic tumor to form duct like structures. Enucleation or curettage is curative.
This is the 2/3 tumor.
67% - 2nd decade
67% - female
67% -anterior maxilla
67% - associated with an impacted tooth
67% - associated with impacted canine
Oral Pathology Long Course, Odontogenesis and Odontogenic Cysts. 13 Jan 1999. CDR D. Schafer, NNDC Bethesda
Successful Hepatitis B immunization is demonstrated by the production of
Hepatitis B core antibody
Hepatitis B surface antibody
Hepatitis B surface antigen
Hepatitis B e antigen
Hepatitis B care antigen
Hepatitis B core antibody (Anti-HBc): positive in all acute and chronic cases and in
carriers; a marker for infection, not protective. (IgM = early)
Hepatitis B surface antibody: previous exposure to HBV; previous vaccination;
recent HBIG prophylaxis; usually protective (when present with HbsAg, indicates
chronic Hepatitis B)
Hepatitis B surface antigen: positive in most cases of chronic or acute infections
Hepatitis B e antigen: Transiently positive in acute hepatitis and in some chronic cases; reflects Dane particle concentration and infectivity
Hepatitis B care antigen: HBV core component is similar to HBeAg (d)
Reference: Oral Medicine handout
42. When treating the patient undergoing chemotherapy, the following recommendations should be considered except:
Routine use of chlorhexidine to prevent infections
Close all wounds primarily with interrupted sutures
Consider a platelet transfusion if the platelet count is less than 40,000/mm³
Wait 10 days after the granulocyte count has reached 500/mm³ to perform any surgical procedures
May advise reducing or stopping brushing or flossing because of concerns for excessive bleeding which might result
The correct answer is D
Chlorhexidine shows a broad spectrum of antimicrobial activity. It is potent against both gram-positive and gram-negative bacteria as well as against yeast and fungal organisms. Interrupted sutures are less invasive than continuous sutures and a loss of a knot in a continuous suture is more of a risk for increased infection as this exposes more of the wound to the oral cavity. Reducing or stopping brushing and flossing is common if the platelet count is below 20,000/mm³. Normal platelet count is 150,000-400,000/mm³ and a platelet transfusion may be considered if the count is less than 40,000/mm³.
Granulocytes are the WBCs that are neutrophils, eosinophils & basophils.
Ref: National Cancer Institute Monographs, Vol. 9, 1990.
Scopp IW (1973). Oral Medicine. A clinical approach with basic science
Correlation, 2nd edition. C.V. Mosby Co.
43. If a patient presents with a complaint that a “light breeze causes pain”, what is the descriptive term for this condition?
The correct answer is B.
Ref: Capt. Bertrand’s notes dtd 08 Sep 99 Page 13. Allodynia is a non-noxious stimulation that produces pain. Wind on skin and hair, or a light touch stimulates A-beta proprioreceptive fibers.
Psychogenic: conscious and subconscious memories causing pain.
Psychiatric: used when the diagnostician fails to find an anatomic pain source.
Idiopathic: cause unknown.
44. Carcinoma in situ
implies that early invasion into the subepithelial connective tissue has occurred
implies the dysplastic changes involve the entire thickness of the epithelium but no invasion has occurred
generally leads to metastasizing squamous cell carcinoma
may be regarded as a reversible lesion
diagnosis may be made when less than the complete thickness of epithelium demonstrates disorderly maturation
The correct answer is B.
Ref: Regezi & Sciubba (1993). Oral Pathology, 2nd edition, page 106.
Carcinoma in situ is the term used when the entire thickness of epithelium is involved. It’s defined as dysplastic epithelial cells extending from the basal layer to the surface of the mucosa. Epithelium may be hyperplastic or atrophic and may/may not have a layer of parakeratin. The important concept is that no invasion has occurred, even though the atypical epithelial cells can resemble squamous cell carcinoma. Since there’s no invasion, metastasis cannot occur (eliminates statement C). Statement D is false, because carcinoma is not considered reversible. Statement A is false based on the definition of carcinoma in situ. Statement E is false because carcinoma in situ involves the entire thickness of epithelium.
45. Obstructive sleep apnea is most predictably treated by:
Nasal-continuous positive airway pressure (CPAP)
Laser assisted uvuloplasty
Oral mandibular positioning devices
The correct answer is B
Weight loss is usually only effective in the morbidly obese patients. Drugs have had little positive effect in the treatment. The uvuloplasty enlarges the airway so that less obstruction can occur. Success rates have varied and ranged from 15-60%. Side effects of mandibular positioning devices include TMJ pain, facial muscle pain and occlusal changes. Continuous positive airway pressure (CPAP) is applied to keep the airway positive, however, patient compliance may be difficult due to the nasal mask and tubing. This method has been very successful in treating obstructive sleep apnea with a 60-65% success rate.
Ref: Friedlander AH, Walker LA, Friedlander IK & Friedlander AL (2000). Diagnosing and Co-managing Patients with Obstructive Sleep Apnea Syndrome. JADA 131(8):1178-1184.
46. A definitive diagnosis of oral hairy leukoplakia requires the
demonstration of Coxsackie A group virus
demonstration of Epstein-Barr virus-DNA
absence of koilocytes in the spinous cell layer
presence of Fordyce’s granules
presence of Oral Herpes virus
The correct answer is B.
Hairy leukoplakia, which results from hyperplasia of the epithelium, presents as a corrugated white patch most frequently on the lateral borders of the tongue, but occasionally involves the dorsal surface or other mucosal surfaces. Most of these patients are HIV (+). The Epstein-Barr virus could also be found in nasopharyngeal carcinoma and Burkitt’s lymphoma. The Coxsackie A virus can be found in Herpangina and Hand, Foot & Mouth disease.
Ref: Cohen J. (2000). Epstein-Barr Virus Infection. The New England Journal of Medicine, 343(7):481-492.
All of the following are true for non-steriodal anti-inflammatants (NSAIDs) except:
In single, full doses, most NSAIDs are more effective analgesics than full doses of aspirin or acetaminaphen. T
Some NSAIDs can equal or exceed the analgesic effect of usual doses of oral narcotic combination products. T
Some patients respond better to one NSAID than another. T
Adverse effects of all NSAIDs are qualitatively similar to those of aspirin, including GI bleeding, ulceration and perforation. T
Like aspirin, NSAIDs cause irreversible inhibition of platelet aggregation. F
A radiopaque periphery encircling a radiolucency is suggestive of a lesion that is:
slowly growing T Bone sclerosis is the hallmark of chronicity.
rapidly growing F May appear as a demineralized area.
beginning to heal F Healing bone regains mineral component and looks more normal.
traumatically induced F
recently developed F
The correct answer is A.
Reference: Oral Roentgenographic Diagnosis, 4th edition by Stafne and Gilbilisco, W.B. Saunders 1975.
Which of the following medications for the treatment of Type 2 Diabetes acts by blocking the digestion of ingested cargohydrates:
All of the above
Acarbose reduces absorption of sugars and starches in the intestine.
Troglitazone acts by decreasing insulin resistance.
Repaglinide increases the amount of insulin released from the pancreas.
According to the 1997 Advisory statement from the ADA and the American Academy of Orthopedic Surgeons, routine antibiotic prophylaxis is not indicated for patients with prosthetic joint replacements. Which of the following should be considered a potential exception to this;
Type 2 diabetes
Sickle cell anemia
All of the above
American Dental Association (ADA) and the American Academy of
Orthopaedic Surgeons (AAOS), in an advisory statement, suggest
prophylaxis for "high risk" patients. The ADA and AAOS
recommend a single dose of amoxicillin, cephradine, or clindamycin
when prophylaxis is selected. The dentist is ultimately responsible
for making treatment recommendations for his or her patients.
J Am Dent Assoc 1997 Jul;128(7):1004-8
Patients at potential increased risk of hematogenous total joint infection are:
Inflammatory arthropathies: rheumatoid arthritis, and SLE.
Insulin dependent (Type 1) diabetics
1st 2 years following joint placement
Previouis prosthetic joint infections
The histological base of a periodontal pocket may be defined as the
apical level of the periodontal fibers
apical level of the junctional epithelium
coronal level of the periodontal fibers
coronal level of the junctional epithelium
apical to the junctional epithelium
The answer is D
Junctional Epithelium – a single or multiple layer of non-keratinized cells adhering to the tooth surface at the base of the gingival crevice
Ref: CAPT Assad’s Lecture " Periodontal Anatomy and Terminology"
52. All of the following are true about the use of Tranexamic Acid in oral surgical procedures except:
It is indicated for patients on Coumadin therapy
It is indicated for patients with platelet disorders
It negates the fibrinolytic activity of saliva following surgery
It has a protective effect on the integrity of the clot
It is dispensed as a 50 mg solution to be used 4 times a day for 5 days
Correct answer: B
Tranexamic Acid neutralizes thew fibrinolytic effects of saliva by binding to lysine binding sights on plasminogen and plasmin.
Contraindications: Disseminated Intravascular Coagulation, Thrombocytopenia, Thrombotic Thrombocytopenic Purpura or anti platelet medications (Ticlid)
Rx: Tranexamic Acid 10grm/200ml sterile water
Disp: 1 bottle
Sig: Rinse with 10ml four times a day for five days
Ref: CAPT Parker's lecture "Principles of Periodontal Surgery" Aug 1999
The reunion of epithelial and connective tissues with root surfaces and bone after an incision or injury is called:
long junctional epithelium
Correct answer: A
Reattachment: reunion of connective tissue with a root surface exposed by incision or injury, but with viable PDL cells.
New attachment: reunion of connective tissue or epithelium to a pathologically exposed root surface; may include new cementum. (Union is a better word than reunion)
Periodontal Regeneration: architecture and function of the periodontium is completely restored, with new alveolar bone, new PDL and cementum.
Periodontal Repair: reestablishment of continuity without full restoration of architecture and function.
Ref: CAPT Perez "Management of Osseous Defects- Regeneration" Aug 1999
Which of the following are true concerning antibiotics used for periodontal disease:
Atrodox® is effective because its active ingredient is chlorhexidine
Periostat® is effective because the low dose of tetracycline inhibits collagenase release
Actisite® is effective because its active ingredient , tetracycline, is chemically enhanced by the presence of cyanoacrylate
Periochip® is effective because its active ingredient, tetracycline, is released slowly over a two week period
All of the above are true
Correct answer: B
Atrodox®: a doxycycline gel, once delivered into the pocket, it solidifies, then degrades releasing TCN over 7 days.
Periostat®: a prescription medication used in conjunction with scaling and root planing. It is a unique form of doxycycline directed at maximizing the anti-collagenalytic properties of TCN while minimizing the potential for the development of bacterial resistance.
Actisite®: TCN fiber therapy, a monofilament of ethylene vinyl acetate copolymer impregnated with TCN (.5mg/cm)
Periochip®: a 4X5mm firm gelatin strip impregnated with Chlorhexidine that is inserted into periodontal pockets >5mm, designed as a supplement to scaling and root planing
Ref: LCDR Caley "The role of Pharmacotherapeutic Agents in Periodontal Therapy"
Guided Tissue Regeneration (GTR) can be used in all of the following clinical situations except:
Soft tissue root coverage
Guided bone regeneration for ridge augmentation
All of the above are indications for GTR
GTR is a procedures used to regenerate a new periodontal attachment apparatus (new cementum, new periodontal ligament, and new bone) over previously diseased root surfaces via selective cell and tissue repopulation. Regeneration is the treatment of choice, but regenerative therapy is not always possible. Indications for GTR include:
Intrabony defects = two or three walled defects
Furcations = Grade I and II
Alveolar ridge augmentation = Guided Bone Regeneration (GBR)
Based on these facts from Assad and Nichol lecture notes, the answer is e.
Which is true of GTR?
It delays epithelial migration along the root surface
It allows regenerative cells to originate from gingival connective tissue
It involves the placement of a membrane to exclude undesirable cells during the healing process
It allows for healing by long junctional epithelium
Regenerative cells originate from bone and PDL
It results in a new connective tissue attachment with some bone formation
1, 3, 4, 5
2, 3, 4, 5
1, 4, 5, 6
1, 3, 5, 6
2, 3, 4, 6
The objectives of GTR include:
To exclude the epithelium or gingival connective tissue from the defect
To permit pleuripotential cells from the PDL and alveolar bone to repopulate the defect
To maintain volume (space) with a membrane to allow entry of regenerative cells into the defect
To stabilize the blood clot which forms the defect
To yield a new connective tissue attachment vice a long junctional epithelium
Based on these facts, from CAPT Nichol’s Lecture Notes, 1, 3, 5, and 6 are true, so the answer is d.
Chlorhexidine is thought to
alter the cell membrane of bacteria
be effective due to its substantivity
be bactericidal by causing precipitation of cytoplasmic contents
have a pronounced effect on the subgingival microflora
cause epithelial desquamation
increase surface staining of composite restorations
all of the above
0.12% Chlorhexidine gluconate (CHX) (Peridex,Perioguard) is an antimicrobial agent. It acts by binding to bacterial cell membranes causing increased cell wall permeability, leakage, and precipitation of the intracellular contents. It exhibits strong substantivity by binding to all hard and soft tissues in the mouth and is released over an 8-12 hour period. It is a broad-spectrum antimicrobial that is bacteriostatic in low concentrations and bactericidal in high concentrations. The adverse effects of CHX are staining of teeth, restorations, and the dorsum of the tongue. Desquamation rarely occurs (but it does) and is superficial. The answer therefore, is e.
Which of the following statements is/are correct?
In the advanced lesion, bone marrow distant from the lesion may be converted to fibrous connective tissue.
The established lesion shows scarring and fibrosis and can persist for several months without progressing.
In the established lesion, plasma cells predominate and lateral extension of the junctional epithelium may begin.
In the early lesion, plasma cells predominate and early pocket formation may be evident.
In the advanced lesion, periods of quiescence and exacerbation are seen along with cytopathologically altered plasma cells.
This question relates to the pathogenesis of periodontal disease. Periodontal pathogenesis requires the presence of plaque bacteria, in a susceptible host, to induce pathologic changes in the tissue. Gingivitis is subdivided into three stages; the initial, the early, and the established lesion. The initial lesion occurs when plaque is present for 2-4 days and is characterized by acute inflammation. The early lesion is seen from 4-10 days and is evidenced by the infiltration of T lymphocytes. The established lesion occurs in 14-21 days and is characterized by the presence of B-lymphocytes and plasma cells. The junctional epithelium is seen to proliferate and migrate into the effected connective tissue. Large amounts of immunoglobulin are present. There is evidence of complement and antigen-antibody complexes, loss of collagen, fibrosis and scarring. The established lesion may remain stable for years or may progress to the advanced lesion of periodontal disease. The advanced lesion contains all the features of the established lesion. Virulent microorganisms initiate and propagate attachment loss. With the advanced lesion, there is periodontal pocket formation, surface ulceration and suppuration, fibrosis of the gingiva, destruction of alveolar bone and periodontal ligament, tooth mobility and drifting, and eventual exfoliation. With these facts, the correct statements are 2,3,and 5. Therefore, the best answer is a.
EDTA, citric acid, and tetracycline have all been used to condition root surfaces in periodontal surfaces to enhance connective tissue attachment. The following advantages have been ascribed to EDTA over the other two except:
It is better at removing the smear layer and exposing collagen fibers - true
It gives less root sensitivity – true ?
It is not as strong an acid - true
It causes less tissue damage - true
It is more effective at removing endotoxins from cementum – false ?
The answer is E
The studies reviewed in the article “EDTA root surface modification: periodontal benefits” in Biological Therapies in Dentistry, a bimonthly newsletter for dental professionals, September 1998, show that the application of neutral EDTA (24%), effectively removes the smear layer and effectively exposes collagen fibers. Both of these effects favor reattachment. Also , the data reviewed suggest that neutral EDTA is more effective in accomplishing these effects than citric acid.
Citric acid is pH 1; Tetracycline HCL is pH 2.0; EDTA is pH 7.0 - 7.04 or , I
would surmise just by the virtue of the low acidic pH and the necrotizing effects
of citric acid especially, on mucosal flaps and periodontal tissues, that there will
be increased root sensitivity with acidic root modifying agents. Zaman et al
Journal Periodontol 2000 Jul:71(7):1094-9; “EDTA root surface modification:
periodontal benefits” in Biological Therapies in Dentistry, a bimonthly
newsletter for dental professionals, September 1998; Carranza Clinical
Peridontogy 8th ed. pp. 628-29
PH 7.0 – 7.4
Citric acid has been shown in vitro to eliminate endotoxins and bacteria from the
diseased tooth surface. Carranza Clinical Peridontogy 8th ed. pp. 628-29; EDTA
and Citric acid demineralization may enhance human periodontal ligament cell
attachment and orientation to the root surface.
Localized juvenile periodontitis is characterized by which of the following?
progresses 3-4 times faster than adult periodontitis -True
affects lower incisors and first molars with vertical osseous defects -True
bone loss is inconsistent with the amount of local factors present -True
a gram negative obligate anaerobic cocci is considered a primary etiologic microorganism -False
all of the above
The answer is C
Definition of LJP: a disease of the periodontium that occurs in an otherwise healthy adolescent, characterized by rapid loss of alveolar bone, lack of severe clinical signs of inflammation, and sparse plaque accumulation. Destruction is not commensurate with local factors.
Characteristics of LJP:
Onset around puberty (11-15 years of age)
Isolated areas of attachment loss and bone loss
(greater at permanent incisors and 1st molars)
Evidence of local, specific bacterial causes
Actinobacillus actinomyetemcomitans, Capnocytophaga
Rod gram - negative obligate anaerobe, found at the base of pocket
Neutrophil dysfunction is a common feature
Familial distribution of the disease, and there is no identified systemic disease
PF Fedi et al The Periodontic Syllabus, 4th Ed pp 34-35.
*** GC Armitage, Development of a classification system for periodontal diseases and conditions 4(1):December 1999 pp 1-6. Changes in the classification system for periodontal diseases include replacement of “Adult Periodontitis” with “Chronic Periodontitis” and replacement of “Early Onset Periodontitis” with “Aggressive Periodontitis”. Due to the problems associated with classification terminologies that were age dependent or required knowledge of rates of progression, these were discarded. Therefore, highly destructive forms of periodontitis formerly considered under the umbrella of “ Early Onset Periodontitis” were renamed using the term “Aggressive Periodontitis.” In general, patients who meet the clinical criteria for LJP or GJP are now said to have “Localized Aggressive Periodontitis” or “Generalized Aggressive Periodontitis.”
61. Several factors predispose diabetics to periodontitis. Which are correct?
elevated glucose levels in oral fluids can influence microbial flora
impaired erythrocyte function, including phagocytosis may reduce resistance to periodontitis
altered collagen metabolites and vascular changes including stasis
impaired chemotactic and phagocytic activity of polymorphonuclear leukocytes
all of the above
The answer is B
The glucose content of gingival fluid and blood was found to be higher in diabetics.
Thickening of the basement membrane of capillaries may hamper the transport of nutrients.
The increased susceptibility of diabetics to infection has been hypothesized as being due to PMN deficiencies resulting in impaired chemotaxis, defective phagocytosis, or impaired adherence. – Glickman’s Clinical Peridontogy 6th ed. pp. 464-465
Which of the following are routinely performed during initial preparation?
thorough scaling and root planing
definitive occlusal adjustment
extraction of hopeless teeth
removal of amalgam overhangs
replacement of missing teeth
Correct Answer: A (E ?)
The reason for the question is because of answer #2 “definitive occlusal adjustment”. It is described in the references as preliminary occlusal adjustment and odontoplasty. Obvious gross occlusal abnormalities (plunger cusps, initial prematurities, defective marginal ridges) should be evaluated early in treatment and corrected, if necessary. Definitive occlusal adjustment does not occur until phase III therapy.
Bacterial control: Initial preparation or (Phase I Therapy):
Patient instruction and motivation
Extraction of teeth
Scaling and root planing
Removal of overhanging restorations and other plaque retentive areas.
Minor tooth movement
Preliminary occlusal adjustment and odontoplasty
Evaluation of results
Surgical Therapy (Phase II Therapy):
Procedures to reduce or eliminate the pocket-Periodontal surgery.
Correction of mucogingival defects
Placement of dental implants
Root canal therapy.
Restorative Treatment (Phase III Therapy):
Definitive occlusal adjustment
Fixed and Removable Restorations
Maintenance (Phase IV Therapy):
Periodic Recall (Most patients who have been treated for moderate to advanced periodontitis require maintenance at least every 3 months).
Reference: Fedi et al The Periodontal Syllabus, 4th ed. 2000 pp68-69.
The pathway of gingival inflammation into the supporting tissues is
by way of the lymphatics of the periodontal ligament
along the fibers of the periodontal ligament
by the outer periosteum of the alveolar bone
by way of the blood vessels into the alveolar bone
by way of the gingival sulcus through the epithelial attachment
The best answer for this question is D. by way of the blood vessels into the alveolar bone.
The reference used for answering this question was
Carranza, FA. Glickman’s Clinical Periodontology, Seventh Edition, W. B. Saunders Company, 1990.
Gingival inflammation extends along the collagen fiber bundles and follows the course of the blood vessels through the loosely arranged tissues around them into the alveolar bone. The pathway of the spread of inflammation is critical because the pathway affects the pattern of bone destruction in periodontal disease.
During Stage I Gingivitis (also called the Initial Lesion by Page and Schroeder), the first response to the initial gingival inflammation is vascular changes. This vascular change is essentially the dilation of the capillaries and the associated increased blood flow. Changes in blood vessel morphologic features, such as widening of small capillaries or venules, and the adherence of neutrophils to vessel walls, occurs within one week and sometimes as early as two days after plaque has been allowed to accumulate. Leukocytes, which are predominantly polymorphonuclear neutrophils leave the capillaries by migrating through the walls. These cells can be seen in increased quantities in the connective tissue, the junctional epithelium, and the gingival sulcus.
Subtle changes can also be detected in the junctional epithelium and the perivascular connective tissues at this early stage. The nature and the character of the host response determine whether the initial lesion resolves rapidly, with the restoration of the tissue to a normal condition, or evolves into a chronic inflammatory lesion. If it does evolve into a chronic inflammatory lesion, an infiltrate of macrophages and lymphoid cells appears within a few days.
During Stage II Gingivitis (also called the Early Lesion by Page and Schroeder), clinical signs of erythema may appear because of proliferation of capillaries and increased formation of capillary loops between rete pegs or ridges. Bleeding upon probing may also be seen.
There is a leukocyte infiltration in the connective tissue beneath the junctional epithelium. An intensified overall inflammatory cell response compared with what is seen in Stage I lesions is seen. There is an increase in the amount of collagen destruction; the main fiber groups that are affected appear to be the circular and dentogingival fiber assemblies. Alterations in blood vessel morphologic features and vascular bed patterns are also seen.
During Stage III Gingivitis, or chronic gingivitis (also called the Established Lesion by Page and Schroeder), the blood vessels become engorged and congested. Venous return is impaired, and the blood flow becomes sluggish. The Stage III lesion can be described as moderately to severely inflamed gingiva. An intense, chronic inflammatory reaction is observed in histologic sections of this tissue.
A key feature that differentiates the Stage III lesion from the Stage II lesion is the increase in the number of plasma cells, which becomes the predominant inflammatory cell type. These plasma cells invade the connective tissue immediately below the junctional epithelium, deep into the connective tissue, around blood vessels, and between bundles of collagen fibers.
The extension of the lesion into the alveolar bone characterizes a fourth stage that has been called the Advanced Lesion by Page and Schroeder. The extension of inflammation from the marginal gingiva into the supporting periodontal tissues marks the transition from gingivitis to periodontitis. There are changes in the composition of the bacterial plaque associated with the transition from gingivitis to periodontitis.
At interproximal locations, the inflammation spreads into the loose connective tissue around the blood vessels, through the transseptal fibers, and then into the bone through the vessel channels that perforate the crest of the interdental septum. The site at which the inflammation enters the bone depends upon the location of the vessel channels. After reaching the marrow spaces, the inflammation may return from the bone into the periodontal ligament, or from the gingiva directly into the periodontal ligament and from there into the interdental septum.
When viewed facially and lingually, inflammation from the gingiva spreads along the outer periosteal surface of the bone and penetrates into the bone marrow spaces through vessel channels in the outer cortex.
Which of the following will stimulate cementum formation in regenerative techniques:
Calcium sulfate (Cap Set®)
Acellular dermal membrane (Alloderm®)
Type I and III porcine collagen (Bioguide®)
Enamel matrix protein (Emdogain®)
The correct answer is d. Emdogain® J Clin Periodontology 2000 Aug; 27(8): 603-610. The other products are used for guided tissue regeneration to prevent downgrowth of epithelial tissues.
All of the following have shown some clinical correlation with periodontitis except:
Low birth weight babies
The correct answer is c. Pernicious anemia. Fedi Perio Syllabus 4th edition 2000 pg.29 and 90. Ample evidence to show a relationship of periodontal health as an important component in management of some systemic diseases. A relationship is suggested between acute systemic infections and the occurrence of cardiovascular disease that includes myocardial infarction and stroke. Low birth weight babies- believed to occur because accumulation of gram(-) micro organisms such as those found in periodontitis results in increased release of prostaglandin and cytokines which may act on distant sites such as the placenta. Severe Periodontitis is associated with upper and lower respiratory disease such as hospital acquired pneumonia.
In chronologic order, select the proper sequence of healing of a free gingival graft.
re-establishment of epithelial layers
re-establishment of capillary circulation
The correct answer is B.
According to Grant, Stern, and Listgarten in Periodontics, 6th Edition, (C.V. Mosby, St. Louis), 1988, “The first 2 days after a free graft is placed are probably the most critical. The graft is in contact with a fibrin net through which plasma diffuses. Vascularization is evident in about 48 hours. Adequate vascularization is present in about a week. Collagen attachment begins approximately 4 days after grafting, and the graft becomes firm by the tenth day. The surface of the epithelium desquamates during the first 3 to 5 days. A new epithelial surface is derived from the adjacent epithelium and possibly from surviving basal cells. The time necessary for complete reepithelizaion depends on the size of the gingival graft. In 2 weeks, the tissue appears to have reformed, but maturation is not complete for 10 to 16 weeks. Keratinization will be evident about 28 days after the surgery.”
67. Metronidazole (Flagyl) is:
effective against anaerobes and specific aerobic organisms.
primarily effective against anaerobes.
effective in the management of cellulitis and early acute infections.
should be used in combination with penicillin for serious odontogenic infections.
The correct answer is C
Refs: Mosby’s Dental Drug Reference, 1997; P 363-365.
Perio notes dtd 02 Aug 99
Gordon, JM & Walker CB (1993). Current status of systemic antibiotic usage in
destructive periodontal disease. J Perio 64:760-771.
Metronidazole has a broad activity against anaerobic (gram (+) & gram (-)) organisms. It penetrates well into gingival fluid. Can be used in combination with Amoxicillin for treatment of NUG. Rx: 250mg tid for 7 days. It’s not the txmnt of choice for cellulitis or early acute infection since these are dominated by aerobic organisms.
68. The diagnostic difference between a pseudo-pocket and an active periodontal pocket is
the probing depth extending through the junctional epithelium into the connective tissue.
the amount of attached gingiva.
the level of the marginal gingiva.
the apical migration of the junctional epithelium.
the depth of the pocket below the CEJ.
The correct answer is E
Ref: Carranza FA (1990). Clinical Periodontology 7th edition.
In health the periodontal probe tip penetrates 1/3 to ½ the length of the junctional epithelium. In disease, the tip penetrates beyond the apical end of the junctional epithelium. Probing can extend through the coronal fibers of the C.T. attachment, even with normal probing force (eliminates “a”, because this can occur in both pseudo-pockets and periodontal pockets). Attached gingiva, level of marginal and apical migration of the junctional epithelium are not distinct to a true periodontal pocket or pseudo-pocket. Loss of clinical attachment level is the true indicator of periodontal disease and can be used to distinguish pseudo-pockets from a true periodontal pocket.
69. What is the most common bone deformity found in periodontal disease?
The correct answer is D
Ref: Manson JD (1976). Bone morphology and bone loss in periodontal disease. J Clinic Perio, 3:14-42.
Interdental craters are found to represent 1/3 of all deformities and 2/3 of all mandibular defects. There is a higher prevalence of these defects in the posterior segments.
(NOTE: NO QUESTION #70)
71. What cell types have been demonstrated to play a role in gingival attachment to titanium endosseous implants?
epithelial cells and fibroblasts
cellular attachment does not occur
The correct answer is A
Ref: Albrektsson & Zarb (1989). Branemark Osseointegrated Implant-P48.
Epithelial regeneration around well-integrated implants results in a structure similar to the gingival tissues around natural teeth. These cells form a seal that adheres to the implant surface.
Initial treatment to relieve symptoms of necrotizing ulcerative gingivitis (NUG/NUP) should begin with?
Superficial debridement T
An alcohol-based mouthwash and topical antibiotic F
Systemic antibiotic therapy F
Complete scaling and curettage F
Brushing and using chlorhexadine rinses F
Per our lecture notes from the long course the answer is: First Eliminate predisposing factors like “stress”. Then Debride plaque and calculus, give OHI and institute systemic antibiotics if needed. Use Peridex BID and give home care instructions. Doxycycline 500mg QD.
ADA acceptance of an antiplaque agent requires all of the following except:
Double blind protocol T
Six month duration of protocol T
Must show statistically significant effect on both bacteria and gingivitis T
Must be used in a manner “representative of normal use” T
Must be confirmed in four independent studies F
Again, in the long course the answers were:
Population should represent typical users.
Product should use a normal regimen
Parallel studies are acceptable
Samples should evaluate plaque quality and quantity, statistically significant effect.
Opportunistic infections must not develop
Confirmed by at least 2 independent studies
6 month duration of protocol
Source: ADA website at www.ada.org Under adjunctive dental therapies for the reduction of plaque and gingivitis.
Compared to young adult nonsmokers, young adult smokers have more:
Subgingival calculus?? Calculus yes! Sheeham and Ishmael
Pockets deeper than 4mm T
Loss of periodontal attachment T
All of the above (Answer)
All bone grafts require:
A non-bleeding bed F
Intimate contact with the recipient surface T
Transmucosal stimulation F
Non rigid fixation F
Per the long course notes bone grafts require:
A source of osteogenic cells
Mechanically stable wound site
Adequate space between bone surface and membrane
Exclusion of soft tissue from space
All of the following burs have a diameter of 1mm except:
#4 round (1.4mm)
#35 inverted cone (1.0mm)
#57 fissure (1.0mm)
#170 tapered fissure (1.0mm)
#700 cross-cut tapered fissure (1.0mm)
Ref: Sturdevant The Art and Science of Operative Dentistry second edition (135-136)
A shear bond strength of 9-13 Mpa in a dentin-bonding agent is
Equal to that of most traditional glass ionomer cements
An intermediate level of bond strength to dentin
Among the highest in bond strength to dentin
Equal to that of most enamel bonding agents
Glass ionomer cements have shear bond strength of ~10 MPa. *
Second generation DBA had a shear bond strength of 2-7MPa.
Third generation DBA had a shear bond strength of 9-18MPa
Fourth generation DBA had a shear bond strength of 17-24MPa
Fifth generation DBA had a shear bond strength of 21-30 MPa
Ref: *Operative handout/Glass Ionomer Cements 7SEP 99.
Latta & Barkmeier “Dental adhesives in contemporary restorative dentistry” DCNA 42(4), 567-577
Which of the following statements concerning amalgapin retained restorations is correct?
They are not acceptable for large crown buildup restorations. F
The location of amalgapin(s) within the remaining tooth structure is not critical. F
More numerous and smaller amalgapins have greater retentive strength than do large amalgapins
Transverse strength off a restoration is decreased by increasing the number and cross-sectional area of the amalgapins
Should be placed directly below and parallel to the restored cusp tip. F
The answer is C
Increasing the number and cross-sectional area of the amalgapins increases the transverse strength of an amalgapin-retained amalgam restoration.
More numerous, smaller amalgapins have greater retentive strength than fewer large amalgapins, even though they have less total surface area.
The geometric configuration of the amalgapin placement and its relation to the direction of applied force may be significant
Ref: Certosimo AJ “The Effect of Cross-sectional Area on Transverse Strength of Amalgapin-retained Restorations" Operative Dentistry (1991) 16 70-76
In post-radiation patients with xerostomia who use a daily application of mildly acidic sodium fluoride gel (pH 5.8), you may expect the following effect on their conventional glass ionomer restorations:
They will be strengthened
They will show surface crazing
They will experience some surface dissolution
They experience a color shift
They are unaffected
The answer is C
Daily application of topical fluoride gel, 1-% “neutral” sodium fluoride (pH 5.8) led to dissolution of conventional glass ionomer cement restorations. More GI restorations failed when compared to amalgam restorations in-patient who used fluoride supplementation, in post radiation patients.
Ref. Wood, Maxymiw & Mc Comb. “A clinical comparison of glass ionomer (polyalkenoate) and silver amalgam restorations in the treatment of class 5 caries in xerostomic head and neck cancer patients”. Operative Dentistry 1993,18, 94-102.
80. Current thinking suggests, that for patients with class V lesions where heavy occlusion would suggest a diagnosis of abfraction, in the absence of a high decay rate, the restorative material of choice is:
a. Conventional Glass Ionomer (GI)
b. Resin Modified Glass Ionomer (RMGI)
c. Flowable Resin Composite (FRC)
d. Polyacid Modified Resin (PMR)
e. Microfilled Resin Composite (RC)
Restoration of an abfraction lesion requires a restorative material that is best able to withstand the biomechanical forces that caused the lesion. The restorative must have a high modulus of elasticity or flexibility. Increased flexibility of a direct restorative means that the material is less stiff due to less filler particles. According to CDR D’s lecture, “one potential advantage of flowable composites is its flexibility.” In an article by Unterbrink and Liebenberg (Quintessence Int 1999), the authors recommend the use of a flowable composite as the first thin layer of a direct restorative to create an elastic cavity wall. In a review of some literature, I might be inclined to use a hybrid resin composite over a flowable resin composite to restore an abfraction lesion in the absence of caries risk. Since a hybrid is not a choice here, I am inclined to answer c. However, this question requires further study to be sure.
When comparing luting cements, which of the following are true:
Zinc phosphate cements have less compressive strength than resin cements
Resin cements have less tensile strength than glass ionomer cements
Resin cements shrink less than zinc phosphate cements
Polycarboxylate cement is less irritating to the pulp than glass ionomer cement
Zinc Poly-carboxylate cement
Zinc Phosphate cement
Glass Ionomer cement
Compressive Strength (MPa)
Tensile Strength (MPa)
(Rosensteil & others J Pros Dent 1998)
Based on the findings inserted in the table, b is the best answer. I could not find any literature listing the shrinkage for the given cements.
In an aging population, the three factors MOST related to the formation of class V
carious lesions are:
a decrease in oral hygiene efficacy
a change in flow or composition of saliva
exposure of root surfaces
formation of sclerotic dentin
There are factors related to class V lesions and there are factors related to caries. Many can have non-carious class V lesions, so the issue of caries, regardless of lesion site and in any sociodemographic population, is the question. One must consider the role of diet, the role of oral hygiene, the role of saliva, and the role of fluoride in caries risk management. Changes in these factors can have a direct relationship on caries progression or control. So, in this case, 1, 2, and 3 are true. Exposure of root surfaces may subject a person to class V lesions, but 1, 2, and 3 are required for the lesion to become carious in the presence of cariogenic bacteria.
83. When preparing a tooth to receive a direct veneer, which of the following reasons justify removal of sound enamel:
to provide space for opaque and veneer material
to create a rough finish for improved bonding
to allow the margin to be hidden below the gingiva
to create a finish line
to remove the etch-resistant, fluoride–rich surface layer
all of the above
At first I struggled with this question, because I thought it referred to porcelain veneers. Porcelain veneers are indirect restorations. A direct veneer is a resin composite restoration. Enamel preparation before placing a veneer is recommended for the following reasons: (1) to provide space for the material and prevent overcontouring of the restoration; (2) to remove the outer fluoride-rich layer of enamel which may be more resistant to acid etching; (3) to create a rough surface for improved bonding; and (4) to establish a definite finish line. The location of the gingival finish line is based on many factors, but the removal of sound tooth structure just to hide it is not one of them. Therefore, 3 is not a good answer, but the rest are. The answer is d.
Current guidelines (Summitt and Osborne, 92) for Class I and II amalgam preparations include:
If occlusal extension greater than 1.2 mm wide, use retention points.
If occlusal extension less than 1.2 mm, no additional retentive features may be needed.
Extension of class II preparations into occlusal grooves only to the transverse ridge.
No extension of class II preparations into occlusal grooves unless carious, with sealants used to seal fissures.
Preparations should aim for the “1/3 the width between the cusp tips” rule unless caries dictates.
The correct answer is D.
Summitt JB and Osborne JW, Initial preparations for amalgam restorations: extending the longevity of the tooth restoration unit JADA 123:67-72 November 1992.
If the occlusal preparation is faciolingually wider than approximately 1.2 mm and the junction with the approximal preparation occurs near the center of the approximal portion, additional retention features (points or grooves) may not be necessary.
If there is an occlusal extension less than about 1.2 mm wide faciolinually, augment the retention it will provide to the approximal segment with retention points.
There was no statement made in the article with respect to extension to the transverse ridge.
Do not extend Class II preparations into occlusal grooves unless there is diagnosed caries. Seal occlusal fissures with a resin sealant.
Preparation width was the predominant factor in determining success of the restoration; that is , narrower restorations showed less need for replacement.
Which statements about the dentinal smear layer are TRUE?
Must be removed prior to the application of bonding agents. False
Can be produced by high speed, low speed, or hand instrumentation. True
Removal has little effect on increasing dentin permeability False
Effectively removed by the sequential treatment with sodium hypochlorite and EDTA. True
May contain viable microorganisms. True
1, 2, 5
2, 3, 4
1, 3, 5
2, 4, 5
All of the above are correct.
The correct answer is D.
Smear layers are created on hard tissues whenever they are cut with hand or rotary instruments. This thin (1-2 microns) layer of denatured cutting debris is very tenacious and, in fact, is often the surface to which restorative materials are luted. During creation of the smear layer, cutting debris is forced variable distances into dentinal tubules. These so-called smear plugs, together with the smear layer decrease dentin permeability, dentin sensitivity and surface wetness. Bonding adhesive resins to smear layers appears to limit the theoretical bond strength unless the smear layers are loosened or partially removed.
The smear layer acts to occlude dentinal tubules to reduce sensitivity. By allowing it to remain, patient comfort may be achieved prior to natural occlusion of the tubules.
The smear layer could be efficiently removed with the ethylenediaminetetraacetic acid gel preparation.
Kerns DG, et al. Dentinal tubule occlusion and root hypersensitivity. J Periodontol 1991 Jul;62(7):421-8
Pashley DH. Smear layer: overview of structure and function Proc Finn Dent Soc 1992;88 Suppl 1:215-24
86. The following are true for the tunnel preparation except:
They minimize the destruction of tooth structure. True
They minimize the perimeter of the restoration. True
They minimize microleakage. True
Less likely to cut the adjacent tooth. True
Caries easily visualized and removed. False
In an effort to be conservative of tooth structure removal some practitioners advocate a tunnel cavity preparation. This preparation joins an occlusal lesion with a proximal lesion by means of a prepared tunnel under the involved marginal ridge. The marginal ridge remains intact. The adequacy of the preparation access may be controversial. Developing appropriately formed cavity walls and excavating caries may be compromised by lack of access and visibility. Whether or not the marginal ridge is preserved in a strong state is also controversial.
CM Sturdevant in “ The art and science of operative dentistry 3rd ed. Mosby pg. 322. 1995.
Which of the following statements is most accurate concerning casting dental gold alloys to proper dimensions?
Casting shrinkage is compounded by setting shrinkage of die stone, and both may be compensated for by using a hydroscopic investment and 1200-1300 F burnout. False
Casting shrinkage is compensated for by setting expansion of die stone and investment, and by either hygroscopic expansion or high-heat thermal expansion of the investment.
Casting shrinkage is compounded by setting shrinkage of die stone, both of which may be compensated for by using a hygroscopic investment technique and low-heat burnout. False
Casting shrinkage is compensated for by setting expansion of the die stone, by using a non-hygroscopic investment technique, by setting expansion of the investment material, by using a combination of hard and soft waxes, and by an 800-900 F burnout. False
Casting shrinkage and setting shrinkage of the die stone are both compensated for by high-heat thermal expansion of the investment. False
The answer is B
All gypsum materials show a measurable linear expansion on setting. The expansion results from the growth of the calcium sulfate dihydrate crystals and their impingement on one another. The magnitude of expansion varies from one type of gypsum material to another. Normally model plaster develops a setting expansion of 0.2% to 0.3%, dental stone about 0.08% to 0.1%, and high-strength stone about 0.05% to 0.07%. ADA Specification No. 25 lists maximum permissible values of setting expansion of 0.3%, 0.2%, and 0.1% for model plaster, stone, and high-strength stone, respectively.
Expansion of the investment is used to compensate for the shrinkage of the gold casting as it cools during the casting procedure. A total of 1.5 – 2% mold expansion is the aim in most gold casting. During the setting of the investment, an expansion of 0.25% takes place because of the gypsum crystallization process.
The thermal expansion technique depends on normal setting expansion and on heating to a temperature of 482 to 650oC (900 to 1200 oF), depending on the investment and the pattern material to obtain full thermal expansion. The investment is allowed to set in air for at least 45 minutes. After removal of the base former and sprue former the mold is heated to burn out the wax pattern and to obtain thermal expansion.
Additional expansion, called hygroscopic expansion, is obtained if the investment is allowed to set in contact with water This may be accomplished by immersing the invested ring in a temperature-controlled water bath or by adding a measured amount of water to the surface of the investment mold before the initial set. A hygroscopic expansion of 1.5% may be obtained with a hygroscopic investment and a water bath immersion. A hygroscopic expansion technique reduces the need for thermal expansion, and a burnout temperature of 468oC (875 oF) is used. Hygroscopic techniques require the use of special investments and equipment.
In summary the balance of shrinkage and expansion is as follows:
Wax shrinkage + Gold shrinkage = Wax expansion + Setting expansion + Hygroscopic
expansion + Thermal expansion
Reference: Craig, Obrien, Powers (1993) Dental Materials, Properties and Manipulation.C.V. Mosby Company 347, 450-452, 462
Cemented posts with smooth surfaces exhibit less retention. Which surface textures retain dowels better?
All of the above
A serrated or roughened post is more retentive than a smooth one. Controlled grooving of the post and root canal considerably Increase the retention of a tapered post. Contemporary fixed Prosthodontics 2nd edition Rosenstiel 1994 pg.242.
A patient reports with a history of numerous severe galvanic-type reactions following placement of large amalgam restorations. What steps could be done to minimize this potential problem in your next large, pin-retained amalgam restoration?
Use a high copper amalgam.
Polish the restoration as soon as possible after it is adequately set.
Cover the restoration with an unfilled resin.
Precipitate silver nitrate on the restoration.
all of the above.
Galvanism is the process by which different metals in contact with each other (as in amalgam) set up cells and currents. In susceptable individuals, it may lead to electro-galvanically-induced keratoses and lichenoid reactions of the mucosa in contact with amalgam restorations. (Sonis, Dental Secrets, 1994, page 44.
Placing a strip of rubber dam or similar insulator between the contacting dissimilar restorations is a diagnostic technique for relieving and evaluating painful galvanic currents. Treatment modalities are based on severity of pain. In the case of mild pain, nothing is done and corrosion products are allowed to form an insulating cover over the offending restoration. With severe pain that does not improve, placing a composite resin restoration in the amalgam restoration to break the interproximal dissimilar metal contact. For painful currents by occluding restorations, a coating of unfilled light-cured resin over the offending amalgam breaks the metal contact and allows corrosion product buildup. (Williamson R Gen Dent 1996 Jan-Feb;44 (1) 70-73.
A simple method has been described for controlling the galvanic pain that occasionally follows the placement of amalgam restorations. The use of silver nitrate appears to be immediately effective in eliminating this annoying occasional problem. (Watson JF, Wolcott RB J Prosthet Dent 1976 Mar; 35(3): 279-82.
Use of a high copper amalgam or immediate polishing wasn’t found in the literature search as a potential treatment modality for this dental malady.
Which of the following statements concerning dental bur design is correct?
Current bur design calls for positive rake angles with edge angles of 45 degrees
The introduction of the high speed handpiece made crosscut burs more effective
Increased spiral angles on burs increase the efficiency in high-speed operation
Runout is a dynamic test of bur accuracy and can never be less than the bur’s concentricity.
The best answer to this question is d: Runout is a dynamic test of bur accuracy and can never be less than the bur’s concentricity.
Sturdevant CM, Roberson TM, Heymann HO, and Sturdevant JR. The Art and Science of Operative Dentistry, Third Edition. Mosby – Year Book, Inc. 1995.
Statement 1 is false as described below:
The rake angle is the most important design characteristic of a bur blade. For cutting hard, brittle materials, a negative rake angle minimizes fractures of the cutting edge that helps to increase the bur life. A rake angle is said to be negative when the rake face is ahead of the radius (from the cutting edge to the axis of the bur). Increasing the edge angle reinforces the cutting edge of the bur and reduces the likelihood of the blade to fracture. Carbide burs normally have blades with slight negative rake angles and edge angles of about 90. (Page 352)
Statement 2 is false as described below:
Crosscuts are needed on fissure burs to obtain adequate cutting effectiveness at low speeds, but at high speeds, they are not necessary. Because crosscut burs used at high speeds tend to produce unduly rough surfaces, non-crosscut instruments of the same dimension for high-speed use have replaced many of the crosscut sizes originally developed for low speed use. (Pages 348-349)
Statement 3 is false as described below:
There is a tendency toward reduced spiral angles on burs intended exclusively for high-speed operation; a large spiral is not needed in this circumstance to produce smooth operation. At high-speed operation, a smaller angle produces more efficient cutting. (Pages 350)
Statement 4 is true as described below:
Runout is a dynamic test that measures the accuracy with which all blade tips pass through a single point when the instrument is rotated. Not only does it measure the concentricity of the head, but it also measures the accuracy with which the center of rotation passes through the center of the head. Even a perfectly concentric head will demonstrate substantial runout if the head is off center on the axis of the bur, if the neck of the bur is bent, if the bur is not held straight in the handpiece chuck, or if the chuck is eccentric relative to the handpiece bearings. Runout can never be less than the concentricity, and it is usually substantially greater. Runout is more clinically significant because it is the primary cause of vibration curing cutting, and it is the factor that determines the minimum diameter of the hole that can be prepared by a given bur. Because of runout errors, burs normally cut holes measurable larger than the diameter of the bur head. (Page 351-352)
Anderson and Charbeneau showed that 59% of the caries that is missed is :
Class 4 sclerotic dentin
at the dentinoenamel junction
nearest the pulp horns
Removal of the bacterial infection is an essential part of all operative procedures. Because bacterial never penetrate as far as the advancing front of the lesion, it is not necessary to remove all the dentin that has been affected by the caries process. In operative procedures, it is convenient to term dentin as either infected, and thus requires removal, or affected and does not require removal. Affected dentin is softened, demineralized dentin that is not invaded by bacteria. Infected dentin is both softened and contaminated with bacteria. Sturdevant The art and science of Operative Dentistry 3rd edition 1994 pg.99.
Anderson and Charbeneau, A comparison of digital and optical criteria ftr detecting carious dentin. J Pros Dent 1985 53(5): 643-646. 59% of staining occurred at the DEJ. The deeper the cavity preparation, the greater the probablility of finding fuchsin-stainable dentin after excavation of the caries. Infected dentin is both softened and contaminated with bacteria.
92. When bonding a porcelain onlay, the silane coupling agent is used to
improve the bond strength between the resin and enamel.
improve the bond strength between the resin and dentin.
improve the bond strength between the resin and porcelain.
improve the bond strength between the enamel and porcelain.
decrease the viscosity of the luting agent.
The most commonly used chemical agent to improve the etched porcelain to resin bond are silanes. They improve resin wetting and provide additional chemical bonding. Placed properly, the porcelain-resin bond is at least as strong as the enamel-resin bond, making bond failures rare. Chemically they are called coupling agents because they bond diffferent molecules. Silanes, like all coupling agents are bifunctional, each end can react with a different surface, one to the organic porcelain (SiO2) and the other to the organic resin matrix. Three types of silane activation are available for dentistry.
chemically Activated Silanes: these require mixing two liquids, the silane and an acid, 10 to 20 minutes before use.
Acid Activated Silanes: Activation occurs when the silane joins the acid on the restoration.
Preactivated Silanes: These come pre-activated’in the bottle allowing for easy use both inside and outside the mouth.
Ref. The ADEPT Report Volume 1, Number 3 Spring 1990
93. The accepted range of film thickness for luting agents is:
The correct answer is C
Ref: Craig (1997). Restorative Dental Materials, 10th ed. Page 178. According to ANSI/ADA Spec. #96, the maximum film thickness is 25 microns.
94. Dental wax patterns should be invested as soon as possible after fabrication to minimize change in the shape caused by:
drying-out of the wax
relaxation of internal stress
continued expansion of the wax
all of the above
The correct answer is C
Ref: O’Brien WJ (1989). Dental Materials, Properties and Selection , Quintessence. Page 464-465. The distortion of a wax pattern after its removal from the cavity is a function of temperature and time before investing. The closer wax gets to the softening point, the more readily stress is released. Also, the longer a pattern is allowed to remain before investing, the greater the deformation that may occur. The pattern should be stored at low temperatures if not investing immediately.
95. A hand instrument with the number designation 13-80-8-14 would best be described as:
an angle former
gingival marginal trimmer
endodontic spoon excavator
The correct answer is D
Ref: Sturdevant CM (1985). The Art and Science of Operative Dentistry 2nd ed. Page 111-113. The formulas make use of the metric system (mm and tenths of mm for instrument dimensions). For designating the degree of angulation, centigrades are used. These are based on a circle divided into 100 units, as opposed to the 360º circle.
-the 1st figure: blade width in 1/10th mm (1.3mm)
-the 2nd figure: the length of the blade in mm (8mm).
-the 3rd figure: the angle the blade forms with the long axis of the handle in centigrades (14 centigrades).
-the 4th figure: since the cutting edge is at an angle, this # represents the angle made by the cutting edge with the long axis of the handle (80º). **However, when this 4th figure is used, it is placed between the figures representing the blade width and the blade length. This is why the #80 is placed 2nd in the formula.
-bi-beveled hatchet: 3-2-28
-an angle former: 12-85-5-8
-bin-angled spoon: 13-7-14
-triple-angled spoon: 13-7-14
96. Regarding placement of posts, enlargement of the canal increased cervical stresses while post placement decreased these stresses.
The first part is true, but the second part is false
The first part is false, but the second part is true
The entire statement is true
The entire statement is false
The correct answer is A
Ref: Fixed Pros. Notes Pages 57-66.
Abou-Ross (1982). The Restoration of the Endodontically Treated Tooth. JADA,
Stern N & Hirshfield Z (1973). Principles of Preparing Endodontically Treated
Teeth for Dowel and Core Restorations. J Prostet Dent., 30:162-165.
The post width should not be greater than 1/3 the root diameter and the post should be surrounded by 1mm of sound dentin. Do not level off the crown, 1-2mm of cervical tooth structure should be retained or the finish line should be extended cervically to recapture tooth structure. Functional forces acting on the tooth should be transferred from the coronal part through the core and dowel to the root and the supporting bone. The thin tooth structure in the cervical region will always be there regardless of the post placement or not. Hence, this area would still be weak.
The ductility of a metal is usually expressed as?
Yield strength (Force/Unit area or Stress in Mpa where the material begins to deform).
% elongation (answer)
c. Modulus of elasticity (Higher modulus =High stiffness).
Ultimate tensile strength (Maximum stress the material can endure).
Young’s modulus (same as modulus of elasticity).
Which of the following statements is (are) true?
A substance that can serve as a desensitizer must occlude dentinal tubules. Yes, atleast partly.
There are 3 theories of dentinal hypersensitivity. (1). Direct nerve stimulus theory- States that odontoblastic processes are touched and this leads to pain. (2). Odontoblastic transduction theory says that there are nerve synapses in the tooth which is determined to be untrue (3) Branstroms hydrodynamic theory about the movement of fluid in the dentinal tubules being responsible for stimujlating the odontoblastic processes and this causes pain.
Potassium oxalate occludes dentinal tubules. Ferric oxalate is a yes also! Reference Pashley 1986, Jorunal of Endodontics, Vol 12, pp 465-474.
Potassium nitrate occludes dentinal tubules. Yes at a concentration of 5%.
Many people with dentinal hypersensitivity develop a pain/hypersensitivity cycle. YES.
Controlling dentinal hypersensitivity can help to improve home care. Not mentioned but would be YES.
Source: Knight and Lie from Journal of Periodontics 1993 64. Pp.366. The article says that a sharp curet and light cured resin were the most effective at tubule occlusion. CDR Cook said that all the answers appear to be YES. The old exam said that only 2, 4, and 5 are correct.
99. What is the primary purpose for placing a post when restoring an endodontically treated molar?
a. Redistribution of occlusal forces. NO
Strengthening of the remaining tooth structure. Not mentioned.
Strengthens the amalgam by reinforcing it. NO
Retention of the build-up material YES
Scurria, Shugars JADA 1995 Vol 126, pp775. States that dowels should be used only for retention of the core build up. They are used more in the anterior.
100. Pin-retained composite resin substrucures to support cast restorations.
Show less microleakage than amalgam substructures. False. Amalgams are more sensitive in the beginning but through corrosion they seal. Source Bryant RW. 1992 Australian Dental Journal 37(2) 81-87.
Should be allowed to set for 12 hours prior to completion of the crown preparation. False can be prepared right away.
Are hydrophilic (expand due to water absorption. True per Operative Seminar
Have a coefficient of thermal expansion similar to dentin. False: Dentin 11, Composite 30-40. Amalgam 22-28.
Are significantly kinder to the pulp than amalgam substructures False the pulp does not react when amalgam is placed on pulp exposures.
Source: Dental materials notes.
101. When placing a 4mm-implant fixture between two natural teeth, the gap between the adjacent root surfaces should be at least:
The correct answer is E
The distance between implants, center to center must be 7mm (with 3.75- or 4-mm implants). This leaves 3mm of vital bone between implant surfaces or 1.5mm of bone surrounding each implant.
Engelman MJ. Clinical Decision Making and Treatment Planning in Osseointegration, Quintessence books, 1996.
Which of the following are qualities of the tissue-side surface of a properly designed pontic?
highly polished/glazed porcelain
minimal tissue contact
all of the above
The correct answer is C
smooth, properly finished and convex on all surfaces
pinpoint pressure free contact on labial mucosa
emergence profile and pontic length harmonious with the adjacent pontics or abutment teeth to maximize aesthetics
lingual contours confluent with the adjacent teeth or pontic
Ref: Stein; 1966 JPD 16: 251-285
Which of the following are characteristics of Type IV gold alloy as opposed to
Type I gold alloy?
increased tensile strength
increased proportional limit
1, 3, 4
1, 2, 4
1, 2, 3
2, 3, 4
all of the above
The best answer is C
In 1932 the National Bureau of Standards surveyed the alloys being used for dentistry and classified them as follows:
Gold and Platinum (Minimum %)
IV (Extra Hard)
This was known as the ADA specification no. 5 and all types have high noble content. The new ADA specification classifies alloys into 3 groups:
High-noble – Noble metal content > 60% (wt.) and a gold content > 40%(wt.).
Noble – Noble metal content >25%(wt.)
Predominantly base metal - Noble metal content < 25%(wt.)
Hardness is an indicator of an alloys ability to resist local deformation under occlusal load. As the % of gold decreases, hardness increases.
Tensile strength represents the maximum strength of the alloy. Generally, the more gold in the alloy, the lower the yield and tensile strength.
Proportional limit represents the greatest stress that a material will sustain without a deviation from the proportionality of the stress/strain curve. Applications of stress greater than the proportional limit results in permanent deformation. Decreasing the gold content increases the proportional limit.
Elongation measures the ductility of a material. It is a good indicator of burnishability. Type I (softer) gold has higher elongation than a type IV (hard) gold.
Ref: Phillips RW. Science of dental materials. 9th edition 1991. W.B. Saunders
Ref: Craig RG. Restorative dental materials. 10th edition1997. Mosby
Unilaterally balanced articulation (group function) is desirable for:
a young person with steep cuspal inclines in the posterior teeth.
Angle's Class II or III occlusion
A patient wearing a Kennedy Class I RPD
A patient that has experienced mobility in the maxillary premolars due to excursive contacts
A patient with a deep overbite
The correct answer is B
Unilaterally balanced (mutually protected ) occlusion
MIP = all teeth contact
Working side = anterior and posterior group function ( can be progressive)
Non-working side = no contact
Protrusive = anterior guidance, no posterior contacts
Clinical application = current patient scheme?, class II&III jaw relationships, unilateral distal extension RPDs
Which of the following cements is LEAST soluble in the oral cavity?
zinc oxide eugenol
The answer is D
SOLUBILITY / Disintegration (%, ADA Test)
Zinc Oxide Eugenol
Reference: Sturdevant, CM (1995) The Art and Science of Operative Dentistry, 3rd Edition, Mosby-Year Book, Inc p. 275
106. Which of the following are primary reasons for splinting teeth with a fixed prosthesis?
to stabilize loose teeth in a favorable occlusal relationship
to distribute occlusal forces so periodontally weakened teeth do not loosen
to prevent a natural unopposed tooth from migrating
to prevent maxillary central incisors from separating after closure of diastema
1 and 2 only
all of the above
The primary reason for splinting teeth with a fixed partial denture is to overcome mechanical problems associated with long-span edentulous areas. Additional abutments are needed to reduce the stress and deflection of the fixed partial denture. Most information and indications for the use of splinted abutments have been empirically derived. Physiologic demands, however, often surpass the capabilities of the remaining teeth. Loose or periodontally weakened teeth are not good candidates for fixed prosthodontics. A provisional fixed partial denture or extracoronal adhesive resin application are indicated to stabilize loose teeth and distribute occlusal forces off periodontally weakened teeth during periodontal treatment, but a fixed partial denture (splinted or not) is not placed until mobility and disease is controlled. An FPD is used to restore edentulous areas and oppose unopposed teeth, but it is not by definition a splint. A fixed retainer is less invasive for splinting central incisors after diastema closure, unless the teeth require restoration. In short, I find the question confusing and clarification necessary to identify an answer. I think the word “provisional” inserted before fixed partial denture in the question was the intent. My guess would be a, but, as it is worded, abutting on loose or periodontally involved teeth is risky. Answer d is possible too, because the best way to prevent migration of an unopposed tooth is to oppose it or it will also be a loose, periodontally involved tooth.
Yang & others (1999) J Prosthet Dent 81 721-8.
Siegal & others (1999) Dent Clin North Am 43 45-76.
Pollack (1999) Dent Clin North Am 43 77-103.
107. What are the characteristics of cement retained vs. screw retained implant supported prostheses?
not as esthetic
higher rate of porcelain fracture
The characteristics of an implant supported prosthesis, cemented or screw retained, are based on implant protection. They are passive in that, they do not exert lateral forces, but cement retained is more passive, because no torque is applied. Any occlusal forces are light and axially directed, not lateral, but I cannot find favor of one over the other. Esthetics is similar, but a screw hole is harder to hide. My guess is screw retained has a higher rate of porcelain fracture, due to coping design, but it is a guess. The profile is an issue, if they are referring to height requirements, in which case, a cement-retained abutment requires less interarch space. My guess is that “that favor” should be inserted instead of of before cement retained. I cannot find three of the choices that favor cement retained abutments over screw retained abutments, but my guess is c, because 1, 3, and 5 are listed at least three times. 2 and 4 are only listed twice.
108. The most important dimension to select when matching teeth to ceramic restorations is
Hue = the variety of color (red, orange, yellow, green, blue, indigo, violet)
Value = the lightness or darkness of color (black is low value and white is high value)
Chroma = the intensity of color (its concentration or saturation of color)
According to CAPT Santulli’s Fixed Prosthodontic Syllabus, value is the most important dimension to the dentist and it should be selected first. It is the most difficult to change. Raising the value of porcelain is difficult, therefore, always select a shade that is higher in value (lighter) if in doubt because reducing the value is easier. Hue is the second most important dimension to select, followed by chroma. Remember, value>hue>chroma is the order because chroma is the easiest to change and value is the hardest. With this knowledge, the best answer is c.
109. What is the most significant factor in fracture of porcelain on a fixed partial denture?
insufficient thickness of porcelain
contamination of the opaque layer
flexibility of the framework
contamination of the metal
insufficient degassing of the metal
The thickness of the oxide layer, formed from degassing the metal, is critical for porcelain retention. If it is too thin, the chemical bond is insufficient to hold porcelain. If the oxide layer is too thick, the porcelain will fail through that weak layer. Alloys which oxidize readily, such as base metals, must be degassed correctly to avoid too thick of an oxide layer. Oxidation heat treatment, or degassing, is specific for each type of metal and is done to control the thickness of the oxide layer. Poor control causes pre-mature bond failure through the metal oxide or at the metal/metal oxide interface (Rosenstiel 1995). While a through d may be factors contributing to porcelain fracture in a metal ceramic restoration, e is the best answer because the restoration may never make it to the mouth with insufficient laboratory handling.
The condylar element on an arcon articulator is set at 25 degrees and the waxed molar teeth are designed to only have centric contacts. When the completed restorations are tried in the mouth they have protrusive interferences, the mostly likely cause is:
articulator’s condylar inclination is less than the patient’s
plane of occlusion is too steep
patient has too much side shift
articulator’s condylar inclination is more than the patient’s
the cusps of the teeth were waxed too steep
Answer is D
Condylar inclination affects the angulation of the cusps of the teeth in both protrusive and nonworking movements. A steep condylar inclination allows steeper inclines on the cusps of the teeth, while a less steep inclination demands a flatter occlusal surface with shallower cuspal inclination. If the articulator condylar path is set at a steeper angle than that which exists in the patient, the resulting restoration will have cusps that have overly steep inclines. A positive error exists and an occlusal interference may result during a protrusive excursion or during a non-working excursion after the restoration is cemented.
If the articulator inclines are less steep than those of the patient, an error will results, but it will be a negative one – a flatter occlusal surface with shallower cusp inclines in both a protrusive excursion and a non-working excursion. Within limits, a negative error is acceptable provided that centric occlusal contacts are maintained. If an error must be made, one which produces greater clearance is preferred.
Ref: Hobo/Shillingburg/Whitsett. Articulator Selection for Restorative Dentistry. J. Prosthet Dent 1976; 40(4): 35-43
The occlusal records used for the functionally generated path technique represent
the movement of the condyles.
a “Gothic arch” or arrow point design made by the excursions of a maxillary stamp cusp.
the pathways of the opposing cusps within the border movements of the mandible.
Vertical closure in the intercuspal position.
The pathways of the cusps to be restored.
The correct answer is c.
According to Dawson in Evaluation, Diagnosis, and Treatment of Occlusal Problems, 2nd Edition, (Mosby, St. Louis), 1989, p. 410:
Border pathways of the lower posterior teeth are dictated by two different determinants:
The anatomic limits of movement of the condyle-disk assemblies (posterior determinant)
The anterior guidance (anterior determinant)
Functionally generated path procedures, properly used on upper posterior teeth, record directly all possible border pathways of the lower posterior teeth, as they are influenced by both the anterior and posterior determinants.
The shape of the lower posterior teeth has a profound influence on the type of occlusion that is dictated by moving said shapes along the border pathways through the functional wax.
1. Meyer FS: The generated path technique in reconstructive dentistry Part I: Complete dentures,
J Prosthet Dent 9: 354-366, 1959
2. Meyer FS: The generated path technique in reconstruction dentistry Part II: Fixed partial dentures, J Prosthet Dent 9: 432-440, 1959
3. Mann AW and Pankey LD: Oral Rehabilitation: Part I. Use of the P-M instrument in treatment planning and in restoring the lower posterior teeth, J Prosthet Dent 10(1): 135-150, 1960
4. Pankey LD and Mann AW: Oral Rehabilitation: Part II. Reconstruction of the upper teeth using a functionally generated path technique, J Prosthet Dent 10(1): 151-162, 1960
5. Vig R: A modified chew in and functional impression technique, J Prosthet Dent 14(2): 214-220, 1964
6. Zimmerman E: Modifications of functionally generated path procedures, J Prosthet Dent 16(6): 1119-1126, 1966
Shillingburg HT et al: Fundamentals of Fixed Prosthodontics, pp 355-364, 330-333 Chicago, Berlin, London, Tokyo, Sao Paulo, Moscow, Prague, and Warsaw, Quintessence Publishing Co, Inc, 1997
Which of the following anatomic determinants of mandibular movement requires a shorter cusp height during fabrication of a fixed prosthesis.
minimum anterior vertical overlap
minimum anterior horizontal overlap
shallow protrusive condylar inclination
increase in the intercondylar width
1, 2, 3
2, 3, 4
all of the above
The best answer is A
keson JP Management of temporomandibular Disorders and occlusion. 3rd edition
113.When using zinc phosphate cement as a luting agent, it is recommended that you
mix quickly on a cold glass slab
mix slowly over a large area of the glass slab
place cavity varnish on vital teeth prior to cementation
use when insolubility is a desired property
The working time can be varied through incremental mixing (1-2 min) and the use of a cool slab. This also allows more powder to be incorporated, which increases the strength of the cement.
Advantages: Easy to use/manipulate, successful clinical record, medium strength, film thickness (25um), low cost, and excess is easily removed.
Disadvantages: Pulp irritation/sensitivity (pH of 3.0 @ 3min, 4.2 @ 1 hr, 7.0 @48 hrs), moderate solubility in oral fluids leading to washout, and there is no chemical bond to tooth or restoration.
Reference: Dr. Santulli’s handout
According to Grippo, what is the best definition of abfraction?
Physiochemical deterioration of teeth by swelling, crazing,softening,etc
Synergistic interaction of mechanical stress and chemical corrosion
Microcracking of tooth with physical or physiochemical wasting
Loss by mechanical friction
Loss by acid and mechanical friction
The term “abfraction” has been used to supplant erosion because it seems more appropriate when describing the loss of tooth substance attributable to effects of occlusal loading forces as well as the physiochemical breaking that occurs during stress corrosion.
Reference: Grippo JO Noncarious cervical lesions: the decision to ignore or restore. J Esthet Dent 1992 55-64.
All of the following are appropriate ways of managing a fixed partial denture on a mesially tilted molar except:
Design the posterior abutment with an occlusal offset and shoulder.
Fabricate the FPD with a proximal half-crown on the distal abutment
Use of a non-rigid connector
Use a telescoping crown on the posterior abutment
Orthodontically upright the molar
The treatment of choice is uprighting by orthodontic tx. This places the abutment tooth in a better position for preparation and distribution of forces.
A proximal half crown can be used as a retainer on the distal abutment. This is a ¾ crown that has been rotated 90 degrees so the distal surface is uncovered.
A telescope crown and coping can also be used as a retainer on the distal abutment. A full crown preparation with heavy reduction is made to follow the long axis of the tilted molar. An inner coping is made to fit the preparation, and the proximal half crown that will serve as the retainer for the fixed partial denture is fitted over the coping. This restoration allows for total coverage of the clinical crown while compensating for the discrepancy between the paths of insertion of the abutments. The marginal adaptation for this restoration is provided by the coping.
The nonrigid connector has the full crown preparation on the molar, with its path of insertion parallel with the long axis of that tilted tooth. A box form is placed in the distal surface of the premolar to accommodate a keyway in the distal of the premolar crown.
Which of the following elastomeric impression materials has the poorest recovery from deformation?
The rank order for permanent deformation following strain in compression, in increasing order, for the four kinds of non-aqueous elastomeric impression materials is: 1) addition silicone 2) condensation silicone 3) polyether 4) polysulfide. Recovery of elastic deformation following strain is less rapid for the polysulfides than for the other three kinds of materials. Since these materials are visco-elastic, fairly rapid, repeated straining, as when teasing an impression out of the mouth, will increase permanent deformation.
Reference: Phillips RW Skinner’s Science of Dental Materials. 8th edition. 1982 WB Saunders Co. pg. 145.
Which of the following assist in more complete seating of full gold crowns during cementation?
placing axial grooves on the preparation after final impression
1, 2, 3
1, 2, 4
2, 3, 4
all of the above
The best answer to this question is e. all of the above.
The reference used for answering this question was
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, and Brackett SE. Fundamentals of Fixed Prosthodontics, Third Edition. 1997. Quintessence Publishing Co., Inc., pages 312 - 313 and 405 – 406.
Several problems can result from incomplete seating of the restoration. Factors that can influence the completeness of the seating of the crown are the viscosity of the cement, the morphology of the restoration, vibration, venting, and seating force. In one study that was cited by the authors of this textbook (Oliviera JF, Ishikiriama A, Vieira DF, and Mondelli J. Influence of pressure and vibration during cementation. Journal of Prosthetic Dentistry, 1979; 41: 173-177.), the investigators determined that vibration produced an improvement of 27 m in the seating of full crowns.
Venting full crowns will facilitate the escape of cement from crowns and allow more complete seating of the crown. Normally adequate seating can be achieved without venting full crowns. Practitioners can encounter problems with preparations with unusually long, nearly parallel axial walls. Drilling a hole in or near the occlusal surface of the full crown provides the most effective venting of full crowns; however, this leaves a defect in the crown after cementation.
Various methods have been proposed for sealing the vent hole such as placement of direct filling materials, metal screws, and cemented plugs. Venting can also be achieved without perforating the crown by creating an internal escape channel in the form of an unoccupied vertical groove in the axial wall of the preparation or in the internal surface of the crown. The groove should begin at the occlusal surface and end short of the gingival finish line.
If the groove is prepared before the impression is made, the groove on the surface of the die must be blocked out before the wax pattern for the crown is made. Blocking out the groove will prevent wax, and ultimately, metal from filling the groove; without the metal in the groove, an internal escape channel for the cement is provided. My assumption is that one could also prepare the groove after the impression is made; this would eliminate the need to block out the groove in the die.
After the die is prepared, relief should be applied to the preparation area of the die to provide space for the cement. Enamel and lacquer have been used for this purpose. The thickness of the overall relief varies with the number of coats applied, the brand of die spacer used, and the care with which the material is applied. A relief of 20 – 40 m is desired. Die spacer is applied to within 0.5 mm of the finish line of the preparation.
A casting made on a die that has relief provided will have a space between it and the preparation when it is placed on the tooth. Full veneer crowns with grooves will seat more completely if a spacer is used, whether or not it is actually placed inside the grooves.
Retention is the property provided by the geometric configuration of the tooth preparation that enables the restoration to resist
removal along the path of insertion.
dislodgment by shear or oblique forces.
movement caused by the compressive forces of occlusion.
The correct answer is A
Ref: Shillingburg (1981). Fundamentals of Fixed Prosthodontics 2nd edition, Page 79.
When a tooth has adequate attached gingiva, which of the following factors is most likely to contribute to increased pocket depth when the tooth is restored with a ceramo-metal crown?
Overcontouring the facial surface of the crown.
Impingement of a temporary crown on the gingival attachment for a period of 2 weeks.
Using retraction cord containing epi.
Placing the margin at the epithelial attachment.
Creating an inadequate proximal contact.
The correct answer is B or D
Ref: Newcomb GM (1974). The relationship between the location of subgingival crown margins and gingival inflammation. J Perio, 45:151.
Overcontouring of the crown will cause a plaque trap. The local factors can cause gingival recession, but it’s not the most likely contributor compared to the other choices.
Placement of retraction cord can cause recession if not used judiciously. The fact that it contains epi doesn’t increase chances of causing recession.
An open contact causing food impaction can cause gingival recession, but is not the major cause.
An assumption here may be being made that the epithelial attachment is referring to the junctional epithelium only. The gingival attachment refers to the entire attachment (CT & junctional epith.). Therefore, impingement on the gingival attachment could cause injury as far down as the CT attachment. This is more destructive than just involving the epithelial attachment.
Location of gingival finish lines in crown preparations is usually influenced by:
crown length available
oral hygiene practices
all of the above
The correct answer is E
Ref: Rosentiel et al (1995). Contemporary Fixed Prosthodontics 2nd ed., P. 143.
Wherever possible, the margin should be supragingival. Subgingival margins have been identified as a major factor in perio disease, particularly when they encroach the epithelial attachment.
In an ideal (Class I) cusp-fossa relationship, the mesiolingual cusp of the maxillary 1st molar occludes with the:
distal fossa of the mandibular 2nd premolar
mesial fossa of the mandibular 2nd molar
central fossa of the mandibular 1st molar
distal fossa of the mandibular 1st molar
mesial fossa of the mandibular 1st molar
The correct answer is C
Ref: Okeson JP (1985). Management of TMD and occlusion, 3rd ed.
Angle describes the Class I relationship as:
The MB cusp of the mandibular 1st molar occludes in the embrasure b/w the maxillary 2nd premolar and the 1st molar.
The MB cusp of the maxillary 1st molar is aligned directly over the buccal groove of the mandibular 1st molar.
The ML cusp of the maxillary 1st molar is situated in the central fossa of the mandibular 1st molar.
Which of the following are true concerning the Hanau H2 articulator?
the condylar path is curved F
Intercondylar distance is fixed T
Anatomical average is used for hinge axis location T
Full range of condylar movement is possible F
all of the above
If you plan on using a Type I zinc phosphate cement for cementing a gold crown, your die spacing technique should provide for a minimum of ______microns space.
ZnPO4 thickness per ADA specification #8 is 25 microns or less. Cements that are less than 25 microns are: Ketac Cem, Tenacin, Durelon, ZnPO4. Materials with high film thickness can affect restoration seating. See Rosenstiel JPD 1998, Sept pp.291.
A ¾ crown used as an abutment for a fixed partial denture will…
have a greater restoration/tooth surface interface than a full crown True (Longer margin length and more marginal area because of complex preparation).
spare tooth structure T
be kinder to the periodontium T
seat more completely during cementation T
be acceptable in a 5 unit 2 abutment fixed partial denture False
1,2,3,4 The answer
all of the above
All of the following cause casting porosity except:
Too large a sprue diameter and/or too short a sprue.
Overheated gypsum investment (causes surface roughness pp 479).
Inadequate burnout (causes incomplete casting pp484).
Inadequate casting force Not Found. But it would because the metal would not reach the extent of the area left by the burntout wax.
Insufficient metal (causes incomplete casting pp484).
Sprue diameter discussed. 10 gauge for molar casting is 2.5mm diameter. 12 gauge or 2mm for premolars. Too long or too small in diameter causes suck back porosity or surface roughness. Rosenstiel Fixed prosthodontics. pp.485. Large sprue improves metal flow and insures a reservoir during solidification. pp.486. You need to make sure the wax patterns are outside the “Thermal Zone”. This is the area in the center of an X across the investment material. Keep the investment material 6mm over the top of the wax pattern. Make sure and wet the ring liner before placing into the ring. This allows more hygroscopic expansion in the investment material. The two types of investment material are:
Gypsum bound for type I, II and III gold alloys.
Phosphate bound for silver-palladium, gold-palladium and nickel-chromium. Casting temperatures over 2100F.
In RPD’s, the anatomy of the occlusal rest should include:
rounded triangular shape
apex nearest center of the tooth
½ the buccal lingual width of the tooth
angle formed with minor connector is less than 90 degrees
a minimum of 1.5 mm of clearance at the marginal ridge
1, 2, 3, 4
1, 2, 4, 5
2, 3, 4, 5
1, 2, 3, 5
all of the above
Answer: b. 1, 2, 4, 5
Ref. McCracken’s Removable Partial Prosthodontics, Seventh Edition. The C. V. Mosby Company, 1985, pages 59 – 60.
Form of the occlusal rest and rest seat:
The outline form of an occlusal rest seat should be a “rounded” triangular shape with its apex toward the center of the occlusal surface.
The outline form should be as long as it is wide, and the base of the triangular shape (located at the marginal ridge) should be at least 2.5 mm for both premolars and molars. If the rest seat is made in smaller dimensions, there is not adequate bulk of metal for the rest. This is particularly true if the rest is contoured to restore the occlusal morphology of the abutment tooth.
The marginal ridge of the abutment tooth at the location of the rest seat must be reduced to provide a sufficient thickness of metal for strength and rigidity of the rest and the minor connector. A reduction of the marginal ridge of approximately 1.5-mm is usually necessary.
The floor of the occlusal rest seat should be apical to both the marginal ridge and the occlusal surface; the floor of the occlusal rest seat should also be concave or spoon-shaped. There should not be any sharp edges or line angles in the preparation.
The angle formed by the occlusal rest and the vertical minor connector from which it originates should be less than 90 degrees. It is only when this situation occurs that occlusal forces can be directed along the long axis of the abutment tooth. An angle that is greater than 90 degrees does not transmit occlusal forces along the supporting axis of the abutment tooth. Instead, it allows slippage of the prosthesis away from the abutment tooth and causes orthodontic forces to be applied. This occurs when forces are applied to an inclined plane.
127. All of the following Kennedy partial denture classifications are possible EXCEPT Class _____, Modification _____.
all of the above
Ref. McCracken’s Removable Partial Prosthodontics, Seventh Edition. The C. V. Mosby Company, 1985, page 19.
Applegate's rules for applying the Kennedy classification:
Classifications should follow rather than precede any extractions of teeth that might alter the original classification.
If a third molar is missing and not to be replaced, it is not considered in the classification.
If a third molar is present and is to be used as an abutment, it is considered in the classification.
If a second molar is missing and is not to be replaced, it is not considered in the classification.
The most posterior edentulous area always determines the classification.
Edentulous areas other than those determining the classification are referred to as modifications and are designated by their number.
The extent of the modifications is not considered, only the number of additional edentulous areas.
There can be no modification areas in Class IV arches. (Another edentulous area lying posterior to the "single bilateral area crossing the midline" would instead determine the classification.)
While observing lateral excursions in your denture patient, the maxillary denture dislodges, but adequate flanges and borders are present. You would
check and adjust the labial frenum area
check and adjust the buccal frenum area
restart the case and have the teeth reset more lingually
increase the thickness of the post-dam area
check the distobuccal flanges for coronoid process impingement
Answer: e. check the distobuccal flanges for coronoid process impingement
Ref: Textbook of Complete Dentures, fifth edition. Williams & Wilkins, A Waverly company, 1993. Pages 412-413.
PROBLEMS WITH MAXILLARY DENTURE:
Dislodgment during functions is a result of (a) overfilled buccal vestibule, (b) overextension in the hamular notch area, (c) inadequate notches for frenum attachments, (d) excessively thick denture base over the distobuccal alveolar tubercle area leaving insufficient space for the forward and medial movement of the anterior border of the coronoid process, (e) placing the maxillary anterior teeth too far in an anterior direction, (f) placing the maxillary posterior teeth too far in a buccal direction, (g) placing the posterior palatal seal too far in a superior direction causing overdisplacement of soft palate tissues, or (h) lack of occlusal harmony. When the teeth do not make harmonious contact, the seal between the tissues and the denture base is often broken. The result is loss of stability and retention.
Dislodgment when the jaw are at rest is a result of (a) underfilled buccal vestibule, (b) inadequate border seal, (c) excessive saliva, or (d) xerostomia.
What is the correct sequence in the preparation of abutment teeth for removable partial dentures?
occlusal rests, proximal guide planes, buccal and lingual contours, polish
buccal and lingual contours, proximal guide planes, occlusal rests, polish
proximal guide planes, occlusal rests, buccal and lingual contours, polish
proximal guide planes, buccal and lingual contours, occlusal rests, polish
proximal guide planes, buccal and lingual contours, polish, occlusal rests
Answer: d. proximal guide planes, buccal and lingual contours, occlusal rests, polish
Ref. McCracken’s Removable Partial Prosthodontics, Seventh Edition. The C. V. Mosby Company, 1985, pages 261-262.
Sequence of abutment preparations on sound enamel or existing restorations:
Proximal surfaces parallel to the path of placement should be prepared to provide guiding planes.
Excessive tooth contours should be reduced, thereby lowering the height of contour so that (a) the origin of circumferential clasp arms may be placed well below the occlusal surface, preferably at the junction of the gingival and middle thirds; (b) retentive clasp terminals may be placed in the gingival third of the crown, for better esthetics and better mechanical advantage; (c) and reciprocal clasp arms may be placed on and above a height of contour that is no higher than the cervical portion of the middle third of the crown and the abutment tooth.
After alterations of axial contours are believed accomplished and before rest seat preparations are instituted, an impression of the arch should be made in irreversible hydrocolloid and a cast poured in a fast-setting stone. This cast can be returned to the surveyor to determine the adequacy of axial alterations before proceeding with rest seat preparations. If axial surfaces require additional axial recontouring, it can be performed during the same appointment and without compromise.
Occlusal rest areas that will direct occlusal forces along the long axis of the abutment tooth should be prepared.
After processing full upper and lower dentures with cusped teeth, selective grinding must be done to correct occlusal errors from fabrication procedures. What is the correct sequence of grinding?
protrusive, centric, balancing, working
centric, protrusive, balancing, working
centric, working, balancing, protrusive
centric, balancing, working, protrusive
centric, working, protrusive, balancing
Before any grinding, evaluate the centric and eccentric positions of the teeth. Record the premature contacts, but do not adjust them. Centric errors are then adjusted first according to the following guidelines. If the cusp is high in centric and eccentric, reduce the cusp. If the cusp is high in centric, but not in eccentric, deepen the fossa or marginal ridge. After these interceptive centric contacts have been corrected, do not reduce the stamp cusps (centric holding cusps) or deepen any fossa. Adjust the shearing cusps instead. The next occlusal error to correct is the laterotrusive, or working, interferences, according to the BULL principle. Adjust the inner inclines (the lingual incline on the buccal cusps of upper teeth and the buccal incline on lingual cusps of lower teeth). Next adjust the mediotrusive, or balancing, interferences. This is very technique sensitive, because it involves the stamp, or centric holding, cusps. Never grind both the upper and lower cusps. Reduce the distobuccal incline of upper lingual cusps or the mesiolingual inclines of lower buccal cusps. Never both! Be careful not to lose your centric relation. Finally, protrusive errors are adjusted. The distolingual inclines of upper buccal cusps and the mesiobuccal inclines of lower lingual cusps are reduced. Therefore, the answer is c.
Which of the following muscles aid in the retention and stabilization of complete dentures?
According to the Textbook of Complete Dentures, atmospheric pressure, adhesion, cohesion, mechanical locks, muscle control, and patient tolerance affect retention. The adaptability of the muscle in the lips, tongue, and cheeks help to stabilize dentures. Therefore, the orbicularis oris is the muscle of the lips and the buccinator is the muscle of the cheek, but the tongue is not listed. Furthermore, 2, 3, and 5 are listed three times, while 1 and 4 are only listed twice. The answer must be e, but the mylohyoid is a not a tongue muscle, but a floor of the mouth muscle. So, the answer may be d. I find no specifics in our Complete Denture Syllabus.
Which of the following characteristics can be true of the dual path of insertion concept for removable partial denture design?
utilization of tooth undercuts adjacent to edentulous areas for retention
tooth replacement of either anterior or posterior edentulous areas
retention gained through minor connectors or proximal plates
most often utilizes an infrabulge flexible retentive component
all of the above
I don’t think anyone would argue that 1 and 2 are true. First, they are basic to any RPD design and secondly, they are choices in four out of five answers. The issue is 3 and 4. Is there retention of a DPRPD through the minor connector or proximal plate? Yes. Does the DPRPD utilize infrabulge retention most of the time? No. The answer is b.
Which of the following statements are true concerning the altered cast technique?
the initial impression is used to fabricate the framework to the remaining teeth
allows for the development of a functional type impression
allows selective tissue impression for more ideal distribution of the load on the distal extension ridge area
the second impression is used to capture the relationship of the framework to the soft tissue
all of the above
Number 1 is true because an initial impression is used to capture the anatomic form of the teeth, but a secondary impression is used to capture the functional form of the residual ridge. So, number 2 is true also. An altered cast technique, or what McCracken refers to as the Selective Tissue Placement Impression Method, allows for the tissues in a distal extension area to be recorded under load and allow for that load to be distributed over as large an area as possible. So, number 3 is true also. Since the framework is used with a tray attached, the relationship of the framework to the tissues is captured in the altered cast technique as well. Therefore, the answer is e, all of the above.
Which of the following is the MOST important factor when making a record of centric relation for complete dentures?
the patient should be in a reclined position
accurate and stable recording bases should be used
central bearing plates and a tracing device should be used
the patient should be allowed to close in his accustomed position when a wax registration is used
the patient should not be allowed to wear their dentures for 24 hours prior to recording centric relation
The most difficult record to make and the most important maxillomandibular relation in complete denture construction is the centric relation (CR) of the mandible to the maxilla. Whatever the method of recording CR, accurate and stable recording bases must be used. The answer is b.
Which of the following statements concerning lingualized occlusion for removable dentures is correct?
results in placement of the mandibular teeth lingual to the ridge crests
uses anatomical teeth for the maxillary denture and modified or semianatomical teeth for the mandibular denture
can not be used effectively when a complete denture opposes a Removable Partial Denture (RPD).
Used to compensate for prognathism and resorbed maxillary arches resulting in the maxillary teeth being set lingual to the mandibular teeth
Concentrates forces of occlusion on lingual cusps of the upper posterior teeth and vertical forces centralized on mandibular teeth
Contraindicated for patients with flat ridges that are unable to resist lateral forces
2, 5, 6
1, 2, 4, 5
2, 3, 5, 6
1, 4, 5, 6
all of the above
The best answer for this question is A: 2, 5, 6.
Distractor # 1: According to Payne and Ortman, the buccolingual position of mandibular posterior teeth is such that the central fossae of each tooth are arranged on a line from the tip of the cuspid to the apex of the retromolar pad. The teeth should not project lingually beyond the mylohoid ridge. (Complete Denture Syllabus, NPDS Course #252, page 56).
Answer # 2: Lingualized occlusion results when the maxillary lingual cusps are the main functional occlusal elements. The maxillary lingual cusps may oppose mandibular 0 or shallow anatomic or semianatomic teeth in balanced or nonbalanced patterns depending upon the needs of the patient. The maxillary lingual cusp articulates with the central fossa of the opposing mandibular tooth. (Parr GR 1982 The occlusal spectrum and complete dentures The Compendium of Continuing education 3:4 July/Aug 241-249; Rahn AO and Heartwell, Jr. CM. Textbook of Complete Dentures, Fifth Edition. Lea and Febiger, 1993, page 367.)
Distractor # 3: Replacement of the missing posterior teeth in the mandibular arch will improve the prognosis of an opposing CD; An RPD may not always be indicated in the mandibular arch though. Properly mounted diagnostics casts are necessary to determine whether a RPD is necessary. When a mandibular posterior occlusion is not replaced, manifestations of the Combination Syndrome may appear. The primary goals when selecting occlusion for fabrication of a single complete denture are harmony of the occlusal plane and the modification of the existing occlusal characteristics to seat and stabilize the prosthesis rather than to dislodge it. Attempts are made to direct forces so that they are perpendicular to the bearing position of the ridge; this seats and stabilizes the denture. The types of teeth selected can be 20 versus shallow cusps, 33 versus 20º, 10º or 0 cusps. (Complete Denture Syllabus, NPDS Course #252, pages 82-85). By inference from these last comments, it appears that lingualized occlusion can be used when a complete denture opposes a removable partial denture.
Distractor # 4: Lingualized occlusion can be used in Class II, and Class III situations. Although the lingualized occlusal scheme is not as flexible as non-anatomic occlusal schemes, lingualized occlusion can be designed using the maxillary or mandibular, buccal or lingual cusps as the functioning element. Some indications for a non-anatomic occlusal scheme however include patient’s in a cross bite, Class II malocclusion, Class III malocclusion, severe residual ridge resorption, excessive interarch distance, poor neuromuscular skills, poor patient adaptability, and when reverse occlusal curve is present in existing dentures. Contraindications to the use of the lingualized occlusal scheme are when repeatable CR records are not possible, pts with pathologic TMJ’s, parkinsonian pts and pts with flat ridges that are unable to resist lateral force. (Parr GR. The Occlusal Spectrum and Complete Dentures. The Compendium of Continuing Dental Education, Jul/Aug 1982; 3(4): 241-248;Complete Denture Syllabus, NPDS Course #252, page 59-63).
Answer #5: This occlusal scheme concentrates forces of occlusion on lingual cusps of the upper posterior teeth.
Answer #6: In the lingualized occlual scheme, there may be reduced lateral forces directed against the alveolar ridges, but, even though lateral forces have been reduced, they still do exist and therefore lingualized occlusion is not recommended for pts with flat ridges that are unable to resist lateral forces. (Parr G The Occlusal Spectrum and Complete Dentures The Compendium of Continuing Dental Education, Jul/Aug 1982 3(4): 241-248; NPDS Course #252, page 59-63).
136. Gagging at denture insertion may be caused by
overextension of the posterior border of the maxillary denture.
overextension of the distal lingual flange of the mandibular denture.
an excessively thick posterior border of the maxillary denture.
a decreased vertical dimension in the final denture.
all of the above
A complete denture patient may develop a gagging or vomiting problem as a result of (1) loose dentures; (2) poor occlusion; (3) incorrect extension or contour of the dentures, particularly in the posterior area of the palate and the retromylohoid space; (4) underextended denture borders; (5) placing the maxillary teeth too far in a palatal direction and the mandibular teeth too far in a lingual direction so that the dorsum of the tongue is forced in to the pharynx during the act of swallowing; (6) excess vertical dimension of occlusion; and (7) psychogenic factors. Patients may refuse to swallow for fear the dentures will dislodge and strangle them. As a result of not swallowing, the saliva accumulates and triggers the gagging reflex (Rahn AO and Heartwell CM. Textbook of Complete Dentures, Fifth Edition; Lea and Febiger; 1993; p. 414).
(1) overextension or underextension of the maxillary posterior border; (2) overextension of the mandibular distolingual flange; (3) inadequate posterior palatal seal; (4) Excessive VDO; (5) maxillary posterior border too thickexcessive VDO; (6) roughness of the denture base; and, (7) malocclusion (8) psychogenic (Complete Denture Syllabus; Naval Dental School; Bethesda, Maryland; NDS Course #252; p.113).
When constructing complete dentures, which of the following factors is determined solely by the patient’s anatomical characteristic?
the compensating curve
orientation of the occlusal plane
Answer is D
The five factors of occlusion are condylar guidance, incisal guidance, compensating curve, occlusal plane and cusp height or angle.
Hanau’s Quint- Simply stated that as any one of the five factors of occlusion is varied, it will affect each of the other four factors.
Centric relation a maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the slopes of the articular eminences. The position is independent of tooth contact. The dentist can control only four of the factors, since the condylar path is fixed by the patient. Of the four that the dentist can control, two of them (the incisal guidance and the plane of occlusion) can be altered only a slight amount because of esthetic and physiologic factors. The important working factors for the dentist to manipulate are the compensating curve and the inclinations, or cusps, on the occlusal surfaces of the teeth.
Ref: Rahn/Heartwell. Textbook of Complete Dentures 5th edition page 250 (1993); Winkler. Essentials of Complete Denture Prosthodontics (1979) Pages 332-335; Naval Dental School. Complete Denture Syllabus (1999-00) page 47
The most reliable landmark for determining the posterior height of the occlusal plane is a point
4mm below the parotid duct
2mm above the resting height of the tongue
midway between the tuberosity of the maxilla and the retromolar pad
at the middle of the retromolar pad
3mm above the crest of the ridge
The correct answer is D.
The anterior height (of the occlusal plane) should be approximately 22 to 24 mm from the depth of the vestibule; while the posterior height should not exceed half the height of the retromolar pad. Rahn and Heartwell in Textbook of Complete Dentures, 5th Edition, (Lea & Febiger, Philadelphia), 1993, p. 271,
A lingual major bar connector should be
located 4 mm inferior to the gingival margin
at least 4 mm in width
considered if more than 8 mm exists between the gingival margin and the floor of the mouth
be added on the inferior border for good tissue contact.
1, 2, 3
1, 3, 4
2, 3, 4
all of the above
The best answer is A
The lingual bar should be used for mandibular RPD’s where sufficient space exists between the slightly elevated alveolar lingual sulcus and the lingual gingival tissues to a place a rigid bar.
It is half pear shaped with the bulkiest portion inferiorly located. Superior border is tapered to the soft tissue. The superior border is located 4 mm inferior to the gingival margins and more if possible. Inferior border located at the ascertained height of the alveolar lingual sulcus when the patients tongue is slightly elevated.
The lingual bar should be at least 4 mm in height and 2 mm in width.
Henderson D. et al. McCrackens’s removable partial prosthodontics. 7th edition. 1985 Mosby
What are the advantages of the RPI clasp design in removable partial dentures as advocated by Krol?
The I-bar is more esthetic in most instances since it contacts the tooth minimally
The I-bar, proximal plate and mesial minor connector provide adequate encirclement of the tooth by engaging more than 200 degrees
The RPI clasp contacts the tooth minimally and is best used on caries-prone patients
A mesial rest eliminates the potential “pump handle” effect that a force on the base would provide with a distal rest
all of the above
In 1973, Krol placed an emphasis on stress control with minimal tooth coverage and minimal gingival coverage (1) (3). The clasp assembly must engage more than 180 degrees to prevent the tooth from moving out of the clasp (2). A mesial rest eliminates the potential “pump handle” effect that a force on the base would provide with a distal rest (4).
Reference: Krol, Arthur. RPI Clasp Retainer and Its Modifications. Dental Clinics of North America. 17(4): 631-649, 1973.
The primary stress-bearing area supporting the base of the distal extension of a mandibular removable partial denture is
the retromylohyoid flange.
the buccal shelf.
the crest of the ridge.
the retromolar pad.
the occlusal rest seats.
The answer is B
Corrected Cast Impressions
Factors influencing Support
Quality of the residual ridge.
Extent of base coverage. In any situation, for the stability of the denture base, it is desirable to have maximum extension within physiologic limits. On the mandibular arch, obviously cover the retromolar pad intentionally and try to load the buccal shelf (with the crest of the ridge being a secondary stress bearing area)
Reference: Removable Partial Denture, NDS Course 259 1998
142. The infraorbital pointer is used for transferring:
a. midline shift
b. hinge-axis relation
c. occlusal plane position
d. radius of condyle reference point
horizontal condylar inclination
The answer is “c”.
The reference used when answering this question was:
Lauciello FR. Anatomic Comparison to Arbitrary Reference Notch on Hanau Articulators. The Journal of Prosthetic Dentistry. Dec. 1998; 40(6).
A maxillary cast is oriented to the Frankfort horizontal plane by using an infraorbital pointer that is attached to the face-bow. The end of the pointer is placed at the lowest margin of the infraorbital rim. When transferred to the articulator, the end of the pointer is placed level with the condylar plane by utilizing the infraorbital indicator, thus orienting the maxillary cast to the (condylar) axis-orbital plane, which closely parallels the Frankfort horizontal plane. Thus the plane of occlusion, when viewed on the articulator, will be similar to that of the patient in an upright position.
The main function of an indirect retainer is to:
Resist the movement of the free end saddle toward the supporting tissue.
Resist the movement of the free end saddle away from the supporting tissue.
Prevent settling of the clasp arms.
Make certain the occlusal forces are directed along the long axis of the abutment teeth.
The correct answer B
Ref: McCracken (1985). Removable Partial Prosthodontics 7th ed. Page 117-126. Direct retainers prevent movement of the free end saddle (distal extension) toward the ridge. Movement of the free end saddle away from the ridge is prevented by indirect retention. Movement of the denture base away from the tissues and about the fulcrum line is prevented by units of the framework that are located on definite rest seats on the opposite side of the fulcrum line from the distal extension. These anterior components should be placed as far as possible from the distal extension base, affording the best possible leverage advantage against lifting of the distal extension base. The fulcrum line is an imaginary line passing through teeth and direct retainers, around which the denture rotates slightly when subjected to various forces directed toward residual ridges.
The median palatal raphe can be relieved in a maxillary complete denture by which of the following methods:
use selective pressure impression techniques.
selectively relieving the case in the median palatal raphe before processing.
using a pressure indicator paste and selectively reduce the denture in the area of the raphe at insertion.
all of the above
The correct answer is B
Ref: McCracken (1985). Removable Partial Prosthodontics 7th ed. Pages 308-309.
Tissues minimally displaced by impression material respond favorably to the additional pressures placed on them by the resultant denture bases if these pressures are intermittent rather than continuous. The selective pressure technique is a combination of extension for maximum coverage within the tissue tolerances with light pressure or intimate contact with the movable tissue. The median palatal rape should not be a main supporting area of the maxillary denture.
To describe an A-P strap major connector for a maxillary RPD, the
Posterior strap is flat, with the central portion thickened to increase rigidity.
Anterior strap is ½ tear drop shaped.
Anterior strap must be kept to a minimum of 4.0 mm from the crest of the gingival margin.
Posterior strap is centered over the junction of the hard & soft palate.
Design is often used when the patient has a palatal torus.
The correct answer is A
Ref: McCracken (1985). Removable Partial Prosthodontics 7th ed. Pages 37-38. The anterior component of the A-P strap is flat (not ½ tear drop shaped) and posteriorly positioned away from the rugae crest (at least 6.0 mm from the gingival margins). The posterior bar is ½ oval and located as far posteriorly as possible, but entirely on the hard palate (anterior to the junction of the hard and soft palate). This design is often used when the patient has a palatal torus, but is not the best choice if the torus is too large and inoperable. A “U”-shaped major connector would be better here.
When viewed from the sagittal plane, what angle is formed between the protrusive and balancing condylar paths?
The correct answer is C
Ref: Occlusion notes (1st lecture):
Fischer angle: angle formed by the inclinations of the protrusive and non-working side condylar paths when viewed in the sagittal plane.
Bennett’s angle: angle formed by the sagittal plane and the path of the advancing condyle during lateral mandibular movements as viewed in the horizontal plane.
Christensen’s phenomenon: space between posterior teeth during protrusion or on the balancing side during lateral excursions.
The positioning of a cast to be surveyed for designing a removable partial denture framework is determined by all of the following EXCEPT: pp198 McCracken
parallel guide planes T
retention areas T
interferences from soft and hard tissue undercuts T
tripod marks F
In a Kennedy Class I RPD, which of the following are indications for lingual plate major connector.
loose anterior teeth T pp.30
high frenum attachments T pp30
extreme vertical resorption of residual ridges allowing little horizontal support T pp30
inadequate space between free marginal gingiva and lingual sulcus T pp24
all of the above
The reciprocal component of an RPD clasp assembly should
contact the abutment tooth immediately after the retentive arm assumes its passive position F
contact the abutment tooth simultaneously with the retentive arm T pp92
be placed in the upper third of the abutment tooth T (“Junction of gingival and middle third”) McCracken pp92 #7. Page 81 “Apical portion of middle 1/3 of crown.
Be attached directly to the major connector F (Not Mentioned)
The main purpose in tilting the cast in surveying is to: pp. 189.
locate the undercuts
locate the height of contours
locate the path of insertion T
locate indirect retentive areas
determine the type of clasps to be used
151. All primary teeth have begun to mineralize at
a. the end of the first trimester
b. the end of the second trimester
two months of age
The best answer is: B
Calcification in the primary dentition occurs on the following schedule in utero:
-central incisors: 14 weeks
-lateral incisors: 16 weeks
-canines: 17 weeks
-Mx first primary molar: 15.5 weeks
-Mx second primary molar: 19 weeks
-Md first primary molar: 15.5 weeks
-Md second primary: 18 weeks
McDonald and Avery, Dentistry for the Child and Adolescent, Sixth Edition, 1994, p. 55
152. How long should a tooth that has been rapidly extruded (3-4 mm/month) be stabilized before being restored.
a. 2 weeks
b. 1 month
c. 2 months
d. 6 months
The answer is: c- 2 months
Definition: orthodontic treatment aimed at moving the tooth root coronally to
lengthen the clinical crown to facilitate prosthetic and/or periodontal treatment.
Rapid: increase clinical crown by 3-4 mm/month overcoming the body’s ability
to deposit bone on crest – moves crown away from bone.
Slow: increase crown length by 1-2 mm/month. Bony crest altered but clinical
crown is not. – i.e. periodontal defect elimination.
Simon: .036 SS wire bisects the canal of the tooth to be extruded, wire hook is cemented into canal, elastics connect hook to wire, 1-3 weeks extrusion time, 8-12 week stabilization
Simon and others, Extrusion of endodontically treated teeth, (1978) JADA 97: 17-23
Nappen: Brackets bonded to adjacent teeth and the tooth to be extruded, the bracket on the tooth to be extruded is placed more apically than those on the adjacent teeth. .016 NiTi wire supplies force for 2-4 weeks, 12 weeks of stabilization.
Nappen and Kohlan, Orthodontic extrusion of premolar teeth: An improved technique (1989) J Pros 61(5): 549-554
Oesterle: .018x.025 wire on adjacent teeth, provisional crown with TMS pin on tooth to be extruded, "o" ring provides force, 1-1.5mm extrusion/week, 8 weeks of stabilization.
Oesterle and Wood, Raising the root, (1991) JADA 122: 193-197
153. Which of the following statements are true concerning the Moyer’s arch length analysis?
1. Radiographs of the mandibular teeth only are required.
2. It predicts space for both the mandible and maxilla.
3. It can predict the size of the second molars.
4. It uses the sizes of the mandibular incisors to predict space required.
5. It predicts the sizes of the cuspids and bicuspids.
6. It can be used for a 5-year-old patient.
The answer is: b- 2, 4, 5
Th Moyer's mixed dentition analysis can be completed in the mouth as well as on casts, and it may be used for both arches. The analysis is based on a correlation of tooth size; the mandibular permanent incisors have been chosen for measuring, because they erupt early and can be measured accurately to predict the size of the maxillary as well as mandibular permanent cuspids and premolars.
McDonald and Avery, Dentistry for the Child and Adolescent, Sixth Edition, 1994, p. 716-717
154. Bone or tooth fractures are best visualized when the X-ray beam is directed to the line of fracture.
The answer is: c- parallel
When the x-ray beam is projected parallel with the plane of a root fracture, the fracture will appear as a sharp radiolucent line between the fragments. If however, the beam is not projected directly parallel through the fracture bus some of the tooth structure is superimposed over its image, it will appear as a more poorly defined gray shadow.
Goaz PW and White SC. Oral Radiology-Principles and Interpretation, Second Edition, C.V. Mosby, 1987, p.725
155. Serial extraction is a method of orthodontic treatment. Which of the following conditions meets an ideal serial extraction case?
1. is indicated more frequently in Class II than in Class I malocclusions.
2. is used only to solve problems of insufficient arch length.
3. is commonly restricted to the primary teeth.
4. a patient with Class I canine and molar relationship with severe crowding and a normal skeletal
5. normal extraction sequence is d’s, c’s and 4’s.
Serial extraction involves the orderly removal of selected primary and permanent teeth in a pre-determined sequence. Its use is indicated only when dental arches are structurally inadequate for the developing teeth and when there is little or no hope of ever attaining a normal size and proportion. Serial extraction is indicated primarily in severe Class I malocclusion in the child with mixed dentition who has insufficient arch length for the amount of tooth material. (Total arch discrepancy of <7mm)
The primary canine is removed first, the first primary molar second, and the first permanent premolar last in the serial extraction procedure.
McDonald and Avery, Dentistry for the Child and Adolescent, Sixth Edition, 1994, p. 784-785
156. Which of the following statements concerning the production of x-rays is not correct?
The filament (cathode) and target (anode) are encased within nitrogen filled glass tubes
The cathode is composed of tungsten
The anode is composed of tungsten
The filament emits electrons in a process termed thermionic emission
Electrons originate at the cathode by the heating of a tungsten filament. X-rays are produced when fast moving electrons are suddenly decelerated in the tungsten target (anode). The filament and target are encased in a glass envelope, whether it is filled with nitrogen I do not know. I cannot find the term thermionic. Therefore, my best guess is d, but further investigation is needed.
All of the following may be part of a child’s development except:
Early mesial shift, the closure of the primate space, occurs from 6-9 years
Late mesial shift, which utilizes the leeway space, occurs from 10-13 years
The average leeway space is 1-2 mm
Flush terminal plane converts to class 1 occlusion in 68% of the population
The primate space is the space mesial to the primary maxillary cuspid and distal to the primary mandibular cuspid. Early mesial shift occurs when the 1st permanent molars erupt (5.5-6.5 years) and cause a mesial shift into the primate space.
The leeway space is the difference between the mesial-distal width of the primary molars and canine compared to the permanent premolars and canine. In the maxilla, the difference is 0.9 mm per side or 1.8 mm per arch. In the mandible, the difference is 1.7 mm per side or 3.4 mm per arch. Some authors will cite 1.2 mm for the maxilla and 2.2 mm for the mandible as averages. In any event it is approximately 1 mm in the maxilla and 2 mm in the mandible per side, but the answer is not specific for side or arch. Late mesial shift occurs when the 2nd permanent molars erupt (11-12 years) and cause a mesial shift of the 1st permanent molars into the leeway space.
Depending on the literature source, flush terminal plane primary molar occlusion will shift to a class I permanent molar relationship in 56-75% of the population. 25-44% will shift into a class II relationship. Answer d is too exacting to be correct.
158. Incisor liability in the maxillary arch is _______ mm and _______ mm in the mandibular arch
Incisor liability is the difference in the mesial-distal width of the permanent incisors and the primary incisors (including interdental spacing). In the maxilla, the difference is 7.6 mm. In the mandible, the difference is 6.0 mm. The answer is c.
The color coding for hazardous chemical warning signs include:
Yellow indicates personal or specific hazard
White indicates a reactive hazard
Blue indicates a health hazard
Level 3 indicates the highest level of danger
Level 1 indicates the lowest level of danger
Levels are not colors. Once I cut and pasted all the information about warning labels from the OSHA and EPA websites, the answer was 10 pages long. Therefore, I offer the bottom line in the above picture of a Hazardous Chemical Warning Label. The answer is c.
Employment medical records must be maintained for the duration of employment plus_____years, training records for______years after the training has taken place.
According to the AGD Impact 18(1):1 6-17 January, 1990 and, OSHA Standards Interpretations and Compliance Letters dated 02/01/1993, medical records should be kept for 30 years which rules out all other answers except answer A. The correct answer is therefore A.
Which of the following statements concerning pediatric physiology and pharmacology are correct?
Children have a higher incidence of laryngospasm than adults.
Children have a wider response range to sedation than adults.
Children have a relatively small epiglottis when compared to adults.
The cardiovascular system in children is less depressed by anesthetic agents than that of adults.
All of the above.
The correct answer is A, reference: AHA Pediatric Advanced Life Support manual 1994 Chap 4.
Which is true concerning Material Safety Data Sheets (MSDS)?
Provided by OSHA
Must be readily accessible to employees
Document physical or health hazards
Lists all ingredients in descending order of their percentage to the total
Does not describe fire or explosion hazards
2, 3, 4
1, 2, 4
Per the OSHA Standards Interpretation and Compliance Letters 02/01/1993, MSDS’s are to be provided by the manufacturer of the material, must be accessible to all employees, must document potential physical and health hazards to the user, must list all Hazardous chemicals percentages, and does describe fire or explosion hazards. The correct answer therefore is B.
OSHA’s definition of regulated waste include all of the following except:
Liquid or semi-liquid blood
Contaminated items that would release blood or other potentially infectious material
Items that are caked with dried blood or other potentially infectious material
Used gloves with dried blood on them
Per the OSHA Standards Interpretation and Compliance Letters 02/01/1993, regulated waste includes liquid or semi-liquid blood, contaminated items that could release blood or OPIM, items that are caked with dried blood or OPIM, contaminated sharps, pathological and microbiological wastes containing blood or OPIM. This rules out answer D as part of the definition of regulated waste and therefore D is the only exception.
164. A child’s toothbrush covered with a full strip of regular strength fluoride toothpaste will contain
Approximately mg of fluoride.
Full strip of toothpaste equals about 1.0mg of fluoride
McDonald/Avery Dentistry For the Child and Adolescent sixth edition Page 265
165. Which is used to assess skeletal imbalance between the maxilla and mandible?
According to Enlow in Facial Growth, 3rd Edition (1990), “The maxilla and mandible may be related to each other anteroposteriorly by the SNA-SNB angles. They are used to access the anteroposterior position of the maxilla and mandible with respect to the anterior cranial base. The difference between the angles – the ANB angle is of interest to the clinician. The mean value of the ANB angle is 2 degrees, and significant deviations from this mean indicate an anteroposterior discrepancy of those basal structures that support the dentition.
“The mandibular plane angle provides a means of assessing vertical relation and the morphology of the lower third of the face. The mandibular plane angle may be measured in relation to the Frankfort horizontal plane (FMA) or in relation to the SN line (SN-MP).”
166. During caries removal in a permanent first molar of a 7-year -old child, a pulp exposure about the size of a #6 round bur is discovered. There is no apparent apical involvement. The treatment of choice is
a. direct pulp cap
b. Cvek pulpotomy
d. formocresol pulpotomy
RCT with calcium hydroxide fill
A Cvek pulpotomy is the amputation of the coronal pulp and placement of a suitable agent (CaOH) on the remaining exposed tissue. The objective is to maintain partial vitality of the remaining pulp in the canal space.
no periradicular or intraradicualr pathology
Vital pulp tissue
At least 2/3 of the root remains
No abscess or fistula
Necrotic pulp tissue
Hx of spontaneous pain
Medically compromised patient.
Buckley’s formacresol –19% Formocresol. 1:5 concentration. Mix 3 parts glycerin with 1 part water. Use 4 parts of this to 1 part Buckley’s FC.
A partial pulpotomy (Cvek technique) consists of amputation of 1 to 2 mm of the exposed pulp, placement of calcium hydroxide powder, and a temporary restoration. The partial pulpotomy technique is a successful and permanent treatment for crown fractures with pulp exposure regardless of the size of exposure, the maturity of the root, or the interval between accident and dental treatment.
CDR Mazzeo Pediatric Dentistry long course. NPDS 2000
de Blanco LP. Treatment of crown fractures with pulp exposure. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996 Nov;82(5):564-8
When treating a patient who is known to have active TB:
Elective treatment can be performed using universal precautions
Elective treatment can be performed when a physician clears the patient based on adequate resolution of symptoms and a negative sputum test.
Emergency treatment should be performed with a HEPA (High efficiency particulate air filter) respirator that meets CDC criteria
Emergency treatment must be performed in a hospital environment with verified positive air flow.
Elective dental treatment is contraindicated in patients with active tuberculosis.
During emergency procedures on TB patients a rubber dam with high speed evacuation and a slow speed hand piece should be used. Respirators capable of filtering infectious particles may also be worn by providers. Reference Shearer, B.G. MDR-TB: Another challenge from the microbial world. JADA 125:43-9, 1994.
Patients who are currently being treated for active disease are usually not infectious after 2-4 weeks and can receive routine dental care. This is confirmed by microscopic examination of a sputum smear. Bloom, R.R. and Murray, C.J.L. Tuberculosis: commentary on a re-emergent killer. Science 257:1055-64, 1992.
Patients with suspected or confirmed tuberculosis are hospitalized in isolation rooms with negative air pressure relative to the rest of the building. Potentially infectious air is vented from the room to the outside of the facility. In addition, cough-producing procedures such as sputum induction are performed in isolation booths with high efficiency particulate air (HEPA) filters. They decontaminate the air before it is returned to the outer room. UV germicidal irradiation of upper air in potentially contaminated rooms confers an extra measure of protection.
Answer is B if the sputum test is clear 3 times on 3 different days.
C is an option only. Not mandatory.
D should be negative pressure air flow. Positive would push air out into the surrounding treatment areas.
168. With the Angle Class II Division II occlusion, which of the following best applies to the maxillary central incisors?
a. normal inclination, the laterals are splayed
b. normal inclination, but bodily forward of the mandibular incisors
c. normal inclination, but bodily behind the mandibular incisors
d. abnormally proclined (splayed facially)
abnormally retroclined (inclined toward the palate)
answer is E
Class II/2 anomalies are characterized by a disto-occlusion of the posterior teeth, a strong palatoversion of two or more maxillary incisors and often a linguoversion of the mandibular incisors.
Ref: Van der Linden F, Boersma H (1987) Diagnosis and Treatment Planning in Dentofacial Orthopedics Quintessence Publishing Co. p 55
169. Which of the following statements concerning caries detection and intraoral radiography are correct.
Active, arrested, and slowly progressive caries appear identical
Occlusal caries are often detected radiographically when they cannot be detected visually or
Caries extending beyond the DEJ discovered on initial bitewing exam should be restored
as quickly as possible
4. Increasing the KVP to increase density and contrast improves diagnostic quality when the radiographs appear too light
The answer is A
According to CAPT Tyler’s Operative Dentistry course notes: Caries which are active, arrested and slowly progressive will be identical on radiographs. Occlusal caries may be detected radiographically and not clinically. If there is no clinical cavitation, lesion can be remineralized and only 40% of approximal lesions exhibiting radiolucencies into the outer dentin were cavitated. See #170 for explanation of KVP effects.
170. A full mouth series of radiographs clearly shows carious lesions. You are more interested in observing bony trabeculations. To increase density and decrease contrast, you would?
a. increase MA
b. increase KVP
c. increase MA, decrease KVP
d. decrease KVP, increase time of exposure
increase both KVP and MA
Radiographic density: the degree of “blackness” or overall degree of darkening of the exposed film. When a film is exposed to an x-ray beam and is subsequently processed, the silver halide crystals that have been exposed to x-ray photons are converted to grains of metallic silver, which give the film its black appearance. The density or blackness of the radiograph varies directly and proportionately as the milliamperage and exposure time. As kilovoltage becomes larger, a greater amount of x-radiation will strike the film emulsion, and result in higher radiographic density if all other factors remain constant.
Radiographic contrast is defined as the difference in densities existing between various regions on the film. A film that shows very light areas and very dark areas is said to have high contrast, whereas a film that shows areas of relatively light grey zones and dark grey zones is said to be of low contrast. The higher the KVp the lower will be the contrast, but the higher KVP will cause increased radiographic density. When the kilovoltage is increased, the MA setting must be decreased to maintain the same radiographic density. Contrast can’t be varied by a change in MA unless a variation in voltage is made to compensate for the milliamperage variation. The higher the mA, and the lower the voltage, the greater the contrast. Density can be altered without changing the contrast. MA is the prime factor in controlling radiographic density but is not a controlling factor in contrast. A change in mA will produce a change in radiographic density but not a noticeable change in contrast.
It is recommended that kilovoltages of 65-70 kVp be used for the bite-wing films in the detection of caries. The kilovoltages in this range produce a high contrast film (short scale contrast) which is good for detection of caries. It is recommended that a high kVp (75-100) technique be used for the periapical films, and a low kVp (65-70) technique be used for the bite-wing film. The high kVp technique would give a long-scale contrast (large number of small density differences) to detect small details in the bone (ie. Trabecular patterns) and a short scale contrast film to detect caries in the teeth.
Reference: Langland, F., Sippy, F., and Langlais, R. Textbook of Dental Radiology. 2nd edition. Charles Thomas Pub. 1984. Pgs. 133,134,138, 451-452.
171. The mandibular primary teeth usually erupt a month or two ahead of the corresponding maxillary teeth. What is the normal eruption sequence of the primary teeth?
a. central, lateral, canine, first molar, second molar
b. central, canine, lateral, first molar, second molar
c. central, lateral, first molar, canine, second molar
d. first molar, central, lateral, canine, second molar
central, lateral, first molar, second molar, canine
The correct answer for this question is c: central, lateral, first molar, canine, second molar.
The reference cited when answering this question was:
McDonald RE and Avery DR. Dentistry for the Child and Adolescent, Sixth Edition. 1994, Mosby-Yearbook, Inc., pages 186-188.
Two different eruption sequences have been advocated. The Logan and Kronfeld chronology of human dentition has been an accepted standard for years. The eruption sequence that their research supports is as follows:
Time of eruption
Mandibular central incisor
Mandibular lateral incisor
Maxillary central incisor
7 ½ months
Maxillary lateral incisor
Mandibular first molar
Maxillary first molar
Mandibular second molar
Maxillary second molar
Lunt and Law carefully reviewed the available literature on the calcification of primary teeth. In addition, they compared their findings with Logan and Kronfeld’s values. Lunt and Law offered a revised table that establishes earlier ages than Logan and Kronfeld’s times for initial calcification. The sequence of eruption that Lunt and Law advocate follows:
Time of eruption
Mandibular central incisor
Maxillary central incisor
Maxillary lateral incisor
Mandibular lateral incisor
Maxillary first molar
Mandibular first molar
Mandibular second molar
Maxillary second molar
In the past, the ages at which the primary teeth erupt have appeared as fixed values such as in Logan and Kronfeld’s table. Lunt and Law suggest that the Logan and Kronfeld’s table be modified. Whereas Logan and Kronfeld suggest that eruption in the mandible is generally ahead of eruption in the maxilla, Lunt and Law suggest that the lateral incisor, first molar, and canine erupt earlier in the maxilla than in the mandible.
Reviewing the current literature confirms that the ages at which primary teeth erupt are two or months later than the times suggested in the Logan and Kronfeld table. It is important to remember that the time of eruption of both primary and permanent teeth varies greatly. Variations of 6 months on either side of the usual eruption date may be considered normal for a given child. Most clinical studies indicate that the teeth of girls erupt slightly earlier than the teeth of boys.
172. The lethal dose of ACT fluoride rinse for a typical 12kg (26lb) child is ____ounces, and the lethal component is the ____:
The correct answer is B (DON’T KNOW REASON, BUT HOPE THE FOLLOWING HELPS FOR SOMETHING):
ACT has .05% NaF which means that the actual ion concentration of fluoride is .025% or .25mg/ml F (.025 x 10) or 250ppm (.025 x 10,000). The certainly lethal dose (CLD) of fluoride is 32-64mg of fluoride per kg. If we use 32mgF/kg, then this 12kg child would ingest 384mgF (32 x 12) for it to be lethal. This converts to 0.384gramsF (384/1000). If 1 gram equals .035oz, then this child would’ve ingested 0.013oz.
173. Which of the following morphologic differences between primary teeth and permanent teeth impact one’s restorative approach to primary teeth?
Enamel thickness is thinner in primary teeth (approx. 1mm) and allows for more shallow preparation.
Pulp horns extend a greater distance into crowns of primary teeth, which may necessitate modification of preparation in that area.
Enamel rods in gingival portion extent gingivally in primary teeth and occlusally in permanent teeth. This factor requires a gingival bevel in Class II preparations in a primary tooth.
Cervical anatomy, an exaggerated bulge, generally is present in the cervical area of the primary teeth and makes adaptation more difficult.
all of the above
The correct answer is B
Ref: Pediatric Dentistry class notes “Diagnosis and Treatment Planning.”
McDonald & Avery “Dentistry for the Child and Adolescent.” Page 60.
-The crowns of primary teeth are wider mesiodistally in comparison with their crown length than are permanent teeth.
-Enamel rods in the gingival portion of primary teeth extend occlusally.
-The cervical ridge of enamel at the cervical 1/3 is more prominent in primary teeth.
174. A 10 year-old patient presents with a contaminated intact permanent central incisor that was avulsed in an accident 45 minutes ago. Prior to replanting the tooth, the tooth should be:
Planed with a curette and rinsed in saline.
Rinsed with a dilute solution of citric acid to remove debris.
Rinsed with Hank’s solution to remove debris.
Rinsed with a solution of sodium fluoride to remove debris.
The correct answer is D
Ref: American Association of Endodontists: The Treatment of the Avulsed Tooth. Endodontic Lecture from long course.
-What to do in this situation: Rinse with Hank’s Balanced Salt Solution, re-plant in an attempt to re-vitalize the pulp, and recall patient q 3-4 weeks for evidence of pathosis. If pathosis is noted, thoroughly clean and fill the canal with CaOH (apexification).
175. Pre-adjusted or straight wire fixed orthodontic appliances are often said to be pre-torqued; this relates to:
The mesio-distal angulation of the crown to the occlusal plane.
The labio-lingual angulation of the crown.
The rotation of the crown.
The relative in and out or labio-lingual position of the crown.
The vertical position of the incisal edges.
The correct answer is B
Ref: Profit W.R. (1986). “Contemporary Orthodontics.” C.V. Mosby Co.
If a non-torqued appliance is used, a third order bend must be placed to compensate for the labio-lingual angulation. Pre-torquing is cutting the bracket slot at an angle. This allows for the horizontally flat rectangular archwire to be placed into the bracket slots without incorporating twist bends.
176. Which of the following is not true regarding mineral trioxide aggregate (MTA):
It is a good substitute for gutta purcha in NSRCT on latex allergic patients
It can be used for perforation repair and as a root end filling material
It is retrievable or re-treatable in NSRCT
It is chemically very similar to building cement
It can be used instead of calcium hydroxide in apexification procedures
Answer: c- It is retrievable or re-treatable in NSRCT
MTA has a composition of 75% Portland cement, 20% Bismuth Oxide and 5% gypsum*(Endo class notes- CAPT Allamang)
Since MTA is basically cement and sets hard I doubt it is retrievable, but I did not find any support for this.
MTA is the first restorative material that consistently allows for the overgrowth of cementum.
It has been advocated for use in the treatment of vertical root fractures, resorption defects, perforation repair and in apexification treatment. It has also been advocated as a direct pulp capping material.
Schwartz, Mauger, Clement and Walker. " Mineral Trioxide Aggregate: a new material for endodontics" (1999) JADA, 130(7): 967-975
Torabinejad and Chivian. " Clinical applications of mineral trioxide aggregate" (1999) JOE 25(3): 197-205
177. The most useful aid in location extra canals is:
use of an operating microscope
use of small size nicke1 titanium files
taking a radiograph from a different angle
use of digital radiography
Answer: c- rotary instrumentation ( the answer given was a- use of an operating microscope)
"Acosta and Trugeda have stated that the ML canal orifice is usually covered by a dentinal rounded growth which conceals the funnel-shaped structure of this canal from view. Textbooks generally mention the use of endodontic explores and/or chemicals to locate the ML canal….Pomeranz and Fishelburg have recommended using a #1 round bur to follow the orifice 1mm below the chamber. Slowey has discussed using a bur in the tacky area found by a sharp endodontic explorer. … The most important step in locating the ML canal is to establish excellent access to the entire pulp chamber."
Kilild and Peters, "Incidence and configuration of canal systems in the mesiobuccal root of maxillary first and second molars" (1990) JOE 16(7): 311-317
178. A tooth is unresponsive to thermal and electrical stimulus, has a definite apical radiolucency, class III mobility, and severe sensitivity to percussion. The clinical diagnosis for the periradicular disease is
a. acute apical periodontitis
b. chronic apical periodontitis
c. acute exacerbation of a chronic apical periodontitis
focal sclerosing osteomyelitis
Answer: c- acute exacerbation of a chronic apical periodontitis
a: acute apical periodontitis -the PDL is normal or widened, no apical radiolucency is present, symptomatic
b: chronic apical periodontitis- Generally asymtomatic periapical lesion that manifests itself radiographically.
c: acute exacerbation of a chronic apical periodontitis- proceeded by chronic apical periodontitis but has symptoms (Phoenix abscess)
d: abscess - an accumulation of purulent exudate
e: focal sclerosing osteomyelitis - low grade, subclinical inflammatory response with an increase in bone density
Reference: Cohen, S., Burns, R.C.; Pathways of the Pulp; Seventh edition; Mosby 1998 pg. 18-19 and 443
The “Balanced Force” technique, advocated by Roane, includes:
Flex-R files used sequentially.
Instrumentation short of the apex, to the apical constriction.
Clockwise/counterclockwise filing motion.
Essentially a step-back preparation technique.
Flaring of canals with Gates-Glidden drills is recommended.
all of the above.
Answer: c- 1,2,3,5
The balanced force technique avoids recognizable transportation of the original
canal path, when used with files that have a modified tip configuration (Flex-R, Moyco/Union Broach, York, Pa).
A no. 15 Flex-R file is marked at the approximate pretreatment radiograph length of the canal. With clockwise and counterclockwise rotation, the file is moved to the predetermined working length. An apex locator and radiograph is used to determine the true working length. The no, 20,25 files are marked 0.5 mm short of the full canal length; the no. 30,35 files are marked 1.0 mm short of the full canal length; and the no. 40,45 files are marked 1.5 mm short of the full canal length. Using the balanced force technique, the no. 20,25 files shape the canal/s. Then utilize the gates glidden burs for coronal flaring as follows: no.6 at 2.0mm, no.5 at 4.0mm., no.4 at 6.0mm, no. 3 at 8.0 mm and no.2 at 10.0mm or short of curvature. Use the no. 30,35 files at determined length 1.0 mm short of full canal length. And complete preparation at 45 file at 1.5 mm length short of the full canal length. Redefine the apical preparation and establish patency between each file to complete canal preparation.
The balanced force technique calls for the oscillation of the preparation instruments right and left with a different arc in each direction. To insert an instrument it is rotated to the right (clockwise) a quarter turn or less as gentle inward pressure is exerted. This action pulls the instrument into the canal and positions the cutting edges “equally” into the surrounding walls. Next, the instrument is rotated left (counterclockwise) at least one third of a revolution. Left-hand rotation attempts to unthread the instrument and drives it from the canal, so the clinician must press inwardly to prevent outward movement and to obtain a cutting action.
Resource: Cohen S. and Burns R. Pathways of the Pulp. 7th edition. 1998. Mosby. 216-218, 244-248.
180. Which of the following statements concerning automated canal preparation is correct?
The vibration of ultrasonic instruments is dampened by contact with the canal wall.
Sonic instruments vibrate at a rate in the range of 25,000 cycles per second and are less effective than ultrasonic instruments.
Engine-driven instruments usually are best for debriding and for use in curved canals.
Automated canal preparations have made hand instrumentation largely obsolete.
Canal Master uses either a slow speed or a Giromatic handpiece with a cutting pilot tip.
The difference between sonic and ultrasonic instrumentation is based on the frequency of vibration. Sonics have frequencies between 1 and 8 KHz and ultrasonics range from 25-40 KHz. Note that 1 KHz is equal to 1000 cycles per second. The mechanism of action is acoustic streaming, which is the flow of fluid from the apical end of the file to the coronal part. It is dependent on the free vibration of the file. This leads to the development of primary and secondary streaming patterns or eddies. Eddies are fluid flows in the opposite directions that generate shear forces. These forces are useful in root canal preparation, irrigation, smear layer removal, post removal, sealer placement, and compaction of gutta percha. The limits of space in a root canal system significantly inhibit the practical utility of ultrasonic devices for cleaning root canals. A canal size of 30 to 40 is required for free oscillation of the instrument. Any contact with the root canal wall dampens oscillations. As the contact with the root canal walls increases, the oscillation is dampened and eventually becomes too weak to maintain acoustic streaming. Small file size with minimal contact of the root canal wall provides optimal cleaning conditions (Endo Lecture Notes and Seminar).
Nickel-titanium instruments can be used effectively for automated canal preparation. Super flexible nickel titanium gives the rotary instruments the ability to ease around curved canals, but they are not necessarily the best and have not made hand instrumentation obsolete (Hulsmann 1993 & 1997). They utilize a crown-down technique to create a continuously tapering preparation from orifice to apex. It is recommended that an electrical handpiece be used because they can maintain the speed more evenly and at the appropriate revolutions per minute. The Giromatic handpiece provides a quarter turn reciprocal movement. While no preparation system results in the complete removal of the smear layer or debris, the Giromatic is reported to be only comparable to hand instrumentation. It is one of many systems on the market, but it is not a product of Canal Master. I find no Canal Master referenced in the literature. The rotary systems reviewed in our course include the ProFile, Quantec, and LightSpeed.
This review has lead to the answer a as the correct statement concerning automated canal preparation.
181. Andreasen has identified the following factors that contribute to the development of inflammatory resorption:
communication with necrotic pulp tissue or an inflammatory zone harboring bacteria
injury to the periodontal ligament
patency of dentinal tubules
all of the above
External resorption after luxation injuries has been described as surface, inflammatory, or replacement resorption. Inflammatory resorption is related to a necrotic and infected pulp. Bacteria and toxins cause inflammation in the adjacent periodontal tissues and leads to progressive resorption of the root via dentinal tubules. Minor injuries to the periodontal ligament and/or cementum due to trauma can induce resorption in the root surface. Endodontic treatment of teeth with external resorption is identical to treatment of other non-vital traumatized teeth. Dressing of the root canal with calcium hydroxide has been shown to give a high frequency of healing. It should therefore be used before filling with gutta percha, especially in immature teeth and those with resorptive perforation (Andreasen 1994). The answer appears to be e.
The standardization of root canal instruments provides that:
instruments #10 to #60 are uniformly color coded and the numbers advance by units of five
the file number represents the diameter of the file in hundredths of a millimeter at the tip
the length of the working blades of files are available in 21, 25, and 30 mm lengths
the diameter at the tip of a #30 file is .30 mm .02 mm
starting with file #10 to #45, the color code is purple, white, yellow, red, green, blue, black and white
all of the above
File handles are color coded, and sizes increase by increments of 5 from size 10 to 60 and increase by increment of 10 from size 60 to 150. The standardized name for each instrument uses numbers from 8 to 150 based on the diameter of the instrument tip measured in hundredths of a millimeter, a point called D1. D1 is diameter at the tip of the blade and D2 is the diameter 16 mm from D1. D3 is the diameter 3 mm from D1. The length of cutting edges (the distance between D1 and D2) remains 16 mm regardless of the length or style of the instrument. The name of each instrument gives considerable information about its dimensions. A size 30 file is indicated to be .30 mm in width at D1 and .30 mm plus .32 mm, or .62 mm, at D2. An instrument is still considered acceptable if it is within .02 mm of the standard. The correct sequence is purple (10), white (15), yellow (20), red (25), blue (30), green (35), black (40), and white (45). Therefore, the answer is d.
The rationale for using calcium hydroxide to repair perforating internal resorption is that:
it reduces the inflammatory response in an oral fluid environment.
it appears to provide an environment conducive to repair.
its alkaline pH spreads through the dentin after placement in the canal system.
an acid pH environment is created, causing hard tissue deposition.