NBDE Prosthodontics and Operative Dentistry 4

Question 1

The 'ferrule effect' in crown preparation refers to:

Accepted Answer

The extension of the crown margin 1.5-2 mm onto sound tooth structure above the finish line

Answer

The ferrule effect is a 360° band of tooth structure at least 1.5-2 mm above the CEJ or finish line, which dramatically increases resistance to fracture.

Question 2

Which type of impression technique is most appropriate for a distal extension removable partial denture?

Accepted Answer

Functional (selective pressure) impression

Answer

A functional impression records the distal extension tissue under simulated functional load, ensuring the denture base is supported under pressure.

Question 3

Glass ionomer cement is uniquely beneficial as a base or liner because it:

Accepted Answer

Bonds chemically to tooth structure and releases fluoride

Answer

Glass ionomer forms a chemical bond with both enamel and dentin and releases fluoride ions, providing both adhesion and cariostatic benefits.

Question 4

When surveying a cast for a removable partial denture, tilting the cast anteriorly will:

Accepted Answer

Increase undercuts on the anterior teeth and decrease them on posterior teeth

Answer

Tilting the cast anteriorly changes the path of insertion, increasing mesial undercuts and decreasing distal undercuts on posterior abutments.

Question 5

The term 'centric relation' in prosthodontics refers to:

Accepted Answer

The most retruded, superior position of the condyles in the glenoid fossae

Answer

Centric relation is a jaw position (not tooth position) defined as the most superior, anterior position of the condyles in the glenoid fossae, reproducible and joint-based.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Prosthodontics and Operative Dentistry 4