Cuestionario: Restorative Dental Materials — 16 preguntas

1. What is the primary objective of restorative dentistry?

A. To replace missing teeth with prosthetic appliances

B. To remove decay or disease and restore proper tooth function

C. To whiten discolored teeth and improve facial appearance

D. To recreate teeth with an artistically pleasing appearance

Answer: (B)

Explicación

Restorative dentistry focuses on removing decay or disease and restoring the tooth’s proper function. Esthetic dentistry, in contrast, emphasizes appearance.

2. A treatment intended mainly to recreate a tooth with an artistically pleasing appearance is best classified as what?

A. Esthetic dentistry

B. Restorative dentistry

C. Periodontal dentistry

D. Preventive dentistry

Answer: (A)

Explicación

Esthetic dentistry refers to recreating a tooth or teeth with an artistically pleasing appearance, whereas restorative dentistry primarily focuses on function.

3. Which description accurately characterizes dental amalgam?

A. A ceramic material fused directly to enamel

B. A tooth-coloured resin composed mainly of organic polymers

C. A silver-only material mixed with water

D. An alloy of silver, tin, copper, and zinc mixed with mercury

Answer: (D)

Explicación

Amalgam is made from an alloy containing mainly silver along with tin, copper, and zinc, mixed with mercury at a 1:1 mercury-to-alloy ratio. It is not composed solely of silver.

4. How does amalgam typically remain retained in a prepared cavity?

A. Through fusion with the surrounding enamel

B. Through micromechanical adhesion from a bonding system

C. Through mechanical retention within the cavity preparation

D. Through chemical bonding to dentinal collagen

Answer: (C)

Explicación

Amalgam typically relies on mechanical retention, although bonded and non-bonded techniques may be used. Micromechanical bonding is characteristic of composite resin.

5. What is the main purpose of condensing amalgam during placement?

A. To compact the material and help remove excess mercury

B. To increase the water content of the restoration

C. To create a tooth-coloured surface layer

D. To make the material chemically bond to enamel

Answer: (A)

Explicación

Condensation tightly compacts amalgam into all areas of the prepared cavity and helps eliminate excess mercury from the mix.

6. Which clinical situation is an appropriate indication for an amalgam restoration?

A. A patient with poor moisture control who needs a durable posterior restoration

B. A small posterior cavity in a tooth exposed to substantial chewing stress

C. All of these situations

D. A severely destroyed tooth requiring a foundation for a future crown

Answer: (C)

Explicación

Amalgam is indicated for stress-bearing posterior cavities, severely destroyed tooth structure, crown foundations, poor moisture control, and several other listed situations. Therefore, all three described situations are appropriate indications.

7. What feature allows composite resin to adhere to tooth structure?

A. Condensation into the prepared cavity

B. Mechanical undercuts without any bonding material

C. A bonding system that provides micromechanical adhesion

D. Chemical fusion caused by mercury

Answer: (C)

Explicación

Composite resin requires a bonding system for micromechanical adhesion to the tooth. This differs from the typical mechanical retention used for amalgam.

8. Which combination represents the principal components of composite resin?

A. Ceramic crystals, gold alloy, water, and phosphoric acid

B. BIS-GMA resin matrix, inorganic fillers, coupling agents, and pigments

C. Glass powder, zinc oxide, eugenol, and amalgam particles

D. Silver alloy, mercury, zinc phosphate, and dentinal tubules

Answer: (B)

Explicación

Composite resin consists of an organic BIS-GMA resin matrix, inorganic fillers, coupling agents, and pigments.

9. A clinician wants to close a diastema and perform esthetic recontouring of a peg lateral. Which material is particularly suitable for these procedures?

A. Zinc phosphate cement

B. Temporary restorative material

C. Dental amalgam

D. Composite resin

Answer: (D)

Explicación

Composite resin is used for diastema closure and esthetic recontouring, including the reshaping of peg laterals.

10. Why is composite resin placed in increments no thicker than 2 mm, with each increment cured before the next is added?

A. To eliminate the need for a bonding system

B. To prevent the material from forming a mechanical undercut

C. To increase mercury release from the restoration

D. To reduce polymerization shrinkage and the risk of open margins

Answer: (D)

Explicación

Incremental placement and curing help reduce polymerization shrinkage, which can otherwise contribute to open margins and recurrent decay.

11. Which property of glass ionomer helps reduce the risk of recurrent decay around a restoration?

A. It chemically adheres to tooth structure and slowly releases fluoride

B. It withstands heavy biting forces through metallic reinforcement

C. It forms a micromechanical bond through a separate bonding system

D. It releases eugenol that sedates the underlying pulp

Answer: (A)

Explicación

Glass ionomer chemically adheres to the tooth and slowly releases fluoride, which helps inhibit decay. Composite resin instead relies on a bonding system for micromechanical adhesion.

12. Which clinical situation is especially appropriate for using glass ionomer?

A. A deep surgical site requiring a hemostatic dressing

B. A primary-tooth restoration or a Class V lesion

C. A large posterior restoration requiring maximum wear resistance

D. A definitive veneer requiring highly esthetic resin

Answer: (B)

Explicación

Glass ionomer is especially desirable for primary teeth and Class V restorations, as well as sealants, core build-ups, and long-term provisional restorations.

13. What is the primary purpose of a temporary restorative material?

A. To create a definitive restoration without further treatment

B. To maintain function and comfort for a limited time

C. To provide a permanent replacement for all lost tooth structure

D. To chemically whiten the tooth during treatment

Answer: (B)

Explicación

A temporary restorative material maintains or restores function and keeps the patient comfortable for a limited period. It is not intended to replace a definitive restoration permanently.

14. What primarily determines the choice between the two major types of temporary restorative materials?

A. The patient’s preference for tooth color alone

B. The fluoride concentration of the patient’s toothpaste

C. The age of the dental handpiece being used

D. The location and amount of tooth structure requiring restoration

Answer: (D)

Explicación

The selection depends on where the tooth is affected and how much tooth structure requires restoration. These factors determine whether a smaller or more extensive temporary material is appropriate.

15. A tooth has lost a filling but has no missing cusp or extensive preparation. Which material is most appropriate for this limited defect?

A. A sealant intended only for intact pits and fissures

B. IRM, a reinforced zinc oxide-eugenol material

C. A provisional material designed to cover most of the tooth

D. A cast restoration placed immediately at the same visit

Answer: (B)

Explicación

IRM is used when a tooth has lost a filling or has a small enamel pit. A provisional restorative material is more suitable when a larger area or prepared tooth must be covered.

16. When is a provisional restorative material specifically indicated?

A. When the restoration must be limited to a small, localized defect

B. When a tooth has only a small enamel pit and no lost restoration

C. When a temporary material is needed solely for a primary tooth expected to erupt soon

D. When a cusp is missing or a tooth has been prepared for a cast restoration involving the gingival margin

Answer: (D)

Explicación

A provisional restorative material is indicated for a missing cusp or a tooth prepared for a cast restoration involving the gingival margin. It may also serve as a temporary crown.