Sample questions with answers
By ealhamdan on 30 Jan 2014
1. When fabricating a provisional restoration by mixing the polymer and the monomer, color instability of the restoration can result. In time, the restoration may become more yellow in appearance. What is the cause?
a. The monomer present is urethane dimethacrylate.
b. The polymer used was methyl methacrylate.
c. Curing the restoration in water at 100° C.
* d. Unreacted benzoyl peroxide is present.
e. None of the above.
Answer: d.
2. When mixing zinc phosphate cement, it is recommended that a dentist mix the cement on a clean, cool glass slab and over a large surface area on the glass slab. Why is this done?
a. To prolong the setting time of the cement.
b. To allow additional powder to be mixed in the liquid portion of the cement so that the compressive strength is higher.
c. To dissipate or lessen the heat of the reaction when the powder and liquid are mixed.
d. To produce a dental cement with reduced solubility.
* e. All of the above.
Answer: e.
3. During the cementation of a complete cast crown, Rosenstiel recommends that you “rock” the cast crown on the preparation from a facial to lingual direction. This is done to:
* a. Accomplish a dynamic seating force that will ensure all excess cement is expressed out and the casting is correctly and fully seated.
b. Take advantage of the resistance features of the preparation.
c. Fully seat the cast crown over any possible undercuts on the preparation.
d. Accomplish a static load that will ensure a binding action of the restoration on the preparation.
e. None of the above.
Answer: a.
4. Imbibition is an inherent physical property that affects the dimensions of certain impression materials. Which of the following is not affected by moisture and will not change the impression dimensionally?
a. Reversible hydrocolloid.
b. Irreversible hydrocolloid.
c. Polyether.
* d. Polysulfide.
e. All of the above.
Answer: d.
5. The polymerization of poly(vinyl siloxane) materials differ from other elastomeric impression materials by the type of reaction. Which of the following is that type of reaction?
* a. Addition polymerization.
b. Condensation polymerization.
c. Free-radical polymerization.
d. Heat polymerization.
e. Irreversible reaction from a sol to a gel.
Answer: a.
6. A disadvantage of the use of poly(vinyl siloxane) impression material is:
* a. Setting inhibition of the impression material caused by some brands of latex gloves.
b. High tear strength of the impression material.
c. The impression material gives off water as a by-product of its polymerization reaction.
d. The impression material gives off alcohol as a by-product of its polymerization reaction.
e. The set material is very rigid.
Answer: a.
7. One would expect to find certain characteristics in a patient with a low or high FMA that might impact on prosthodontic treatment. All of the following are characteristic of a low FMA except:
a. short clinical crowns.
b. increased biting force.
* c. increased zone of attached gingiva.
d. broad and flat palatal vault.
Answer: c.
8. Which of the below stated reasons for the existence of the Curve of Wilson, in an occlusal plane, is false?
a. This alignment of the teeth provides the greatest resistance to masticatory forces.
* b. The outward inclination of the lower occlusal table allows for easy access of food to that surface.
c. The alignment of the posterior teeth parallels the direction of loading from the internal pterygoids.
d. The lower buccal cusps serve as a baffle for food tossed onto the occlusal table from the lingual.
Answer: b.
9. The ADA 1984 classification for dental casting alloys includes each of the following except:
a. High noble metals contain 60 wt% or greater noble metal elements.
* b. Noble metals contain 40 wt% or greater noble metal elements.
c. Noble metal elements include: Au, Ir, Os, Pt, Rh, Ru.
d. Predominately base metal contains less than 25 wt% noble metal.
e. High noble metals contain 40 wt% or greater gold.
Answer: b.
10. Condylar movement occurring on the nonworking side includes all of the following except:
a. Mediotrusion.
* b. Surtrusion.
c. Orbiting movement.
d. Protrusion
e. Inferior lateral pterygoid muscle activity.
Answer: b.
11. What is the average dimension of the biologic width?
a. 0.5 mm.
b. 1 mm.
* c. 2 mm.
d. 3 mm.
e. 4 mm.
Answer: c.
12. Which of the following are components of the biologic width?
* a. junctional epithelium, connective tissue attachment.
b. periodontal ligament.
c. marginal and attached gingiva.
d. dentogingival and alveologingival fibers.
e. cementoenamel junction.
Answer: a.
13. When a periodontal flap is raised for a crown lengthening procedure, wound healing will primarily be:
a. new attachment.
* b. reattachment.
c. regeneration.
d. repair.
e. secondary intent.
Answer: b.
14. The bonding of porcelain to gold alloys was introduced in dentistry in the early 1960s by:
* a. M Weinstein.
b. I Sced.
c. R Dykema.
d. J McLean.
e. F Clark.
Answer: a.
15. Normal rotational opening movement is limited by:
a. The inner horizontal portion of the temporomandibular ligament.
b. The temporalis muscle.
c. The capsular ligament.
d. The mandibular sling created by the masseter and internal pterygoid muscles.
* e. The outer oblique portion of the temporomandibular ligament.
Answer: e.
16. Mutually protected occlusion includes everything below, except:
a. maximum occlusal contact on certain teeth or groups of teeth during centric occlusion or excursive movements.
b. other teeth have light contact or are in disclusion during centric occlusion or excursive movements.
c. during protrusion, the incisors occlude and the other teeth do not.
d. in lateral excursion, the working side canine occludes while the non-working side teeth are in disclusion.
* e.all teeth provide maximum occlusal loading in centric occlusion.
Answer: e.
17. The effect of a shallow angle of eminentia on cusps and fossae is:
a. The more mesial is the cusp path on mandibular teeth.
* b. The shorter the cusps and shallower the fossae must be.
c. The shorter the cusps and shallower the fossae can be.
d. The longer the cusps and deeper the fossae must be.
e. The longer the cusps and deeper the fossae can be.
Answer: b.
18. Which of the following statements regarding the use of astringents in gingival retraction cords is incorrect?
a. Alum, aluminum sulfate and aluminum chloride are astringents.
b. Astringents act by precipitation of proteins.
c. Astringents act by inhibiting transcappilary movement of plasma proteins.
* d. Astringents have relatively high cell permeability.
e. There is no indication that astringents have any systemic manifestations.
Answer: d.
19. Gingival retraction cords impregnated with racemic epinephrine can contain from 0.2 mg to 1.0 mg of this chemical per inch of cord. The maximum dose of epinephrine for a healthy adult patient is:
* a. 0.2 mg.
b. 0.4 mg.
c. 0.6 mg.
d. 0.8 mg.
e. 1.0 mg.
Answer: a.
20. Regarding the restoration of endodontically treated teeth, which of the following statements is incorrect?
a. Crowns should generally be used on endodontically treated posterior teeth.
b Crowns are not necessary on relatively sound endodontically treated anterior teeth.
* c. Posts reinforce endodontically treated teeth.
d. Serrations increase post retention.
e. Threaded post forms are most likely to cause root fracture.
Answer: c.
21. Which of the following impression materials is radiopaque?
* a. Polysulfide rubber base.
b. Polyether rubber base.
c. Polyvinyl siloxaine.
d. Condensation silicone rubber base.
e. All of the above.
Answer: a.
22. Which of the following is true?
* a. Reversible hydrocolloid has excellent moisture resistance, and poor finish line readability.
b. Polysulfide rubber base has good finish line readability, and poor tear strength.
c. Polyvinyl siloxaine has good finish line readability and 12 hour pouring time
d. Polyether rubber base has maximum shelf life of six months and good finish line readability.
Answer: a.