NBDE Ultimate 4

Question 1

The recommended pulpal depth for a Class I cavity preparation using amalgam is approximately:

Accepted Answer

0.5 mm into dentin

Answer

A Class I amalgam preparation should extend approximately 0.5 mm into dentin to ensure adequate pulpal depth (~1.5-2 mm total) for bulk and retention.

Question 2

Which impression material is considered the gold standard for fixed prosthodontic impressions?

Accepted Answer

Polyvinyl siloxane (addition silicone)

Answer

Polyvinyl siloxane (addition silicone) offers superior dimensional stability, excellent detail reproduction, and extended pour time, making it ideal for fixed prosthodontic impressions.

Question 3

Compared to a permanent molar, a primary molar pulp is characterized by:

Accepted Answer

More prominent pulp horns and thinner dentinal walls

Answer

Primary molars have proportionally larger pulp chambers, more prominent (coronally positioned) pulp horns, and thinner dentinal walls, increasing pulp exposure risk during cavity preparation.

Question 4

Formocresol pulpotomy in a primary molar is indicated when:

Accepted Answer

The radicular pulp is vital and hemorrhage is controlled

Answer

Formocresol pulpotomy is indicated when the coronal pulp is inflamed but radicular pulp remains vital, asymptomatic, and hemostasis is achievable after amputation.

Question 5

The primary mechanism by which acid etching improves composite resin bonding to enamel is:

Accepted Answer

Micromechanical retention through resin tag formation

Answer

Acid etching creates microporosities in enamel by selectively dissolving prism cores or peripheries, allowing resin monomers to penetrate and form resin tags for micromechanical retention.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Ultimate 4