NBDE Restorative Dentistry 4

Question 1

A dentist discovers a previously placed composite restoration has secondary caries confined to the margin. The MOST conservative management is:

Accepted Answer

Repair by selectively removing only the carious margin and rebonding

Answer

Selective repair of a marginal defect with secondary caries is the most conservative option, preserving sound tooth structure and the remaining sound restoration.

Question 2

Glass ionomer cement releases fluoride primarily through which mechanism?

Accepted Answer

Sustained diffusion from the set material

Answer

Fluoride ions are entrapped within the set glass ionomer matrix and are released by sustained diffusion over time, providing a caries-inhibiting effect.

Question 3

Which of the following best describes the 'C-factor' in composite resin placement?

Accepted Answer

Ratio of bonded to unbonded surfaces in a cavity

Answer

The C-factor (configuration factor) is the ratio of bonded cavity walls to unbonded free surfaces; a higher C-factor increases polymerization shrinkage stress at the bond interface.

Question 4

A patient presents with a fractured maxillary central incisor involving enamel and dentin without pulp exposure. The FIRST step in treatment is:

Accepted Answer

Cover exposed dentin with a sedative dressing and reassess pulp vitality

Answer

Exposed dentin should be protected and pulp vitality assessed before definitive restoration, as pulpal response can change in the weeks following trauma.

Question 5

In pin-retained amalgam restorations, the most common complication associated with threaded pins is:

Accepted Answer

Dentinal crazing and cracking

Answer

Threaded pins create stress concentrations that cause dentinal crazing and microcracks as the pin is driven into dentin, potentially weakening the tooth.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Restorative Dentistry 4