NBDE Periodontics and Endodontics 3

Question 1

Which test result pattern is MOST consistent with a diagnosis of reversible pulpitis?

Accepted Answer

Exaggerated response to cold that resolves quickly

Answer

Reversible pulpitis produces a heightened but transient response to thermal stimuli that subsides quickly upon removal of the stimulus, indicating the pulp can recover.

Question 2

What is 'biologic width' and why is it clinically significant in restorative dentistry?

Accepted Answer

The combined height of junctional epithelium and connective tissue attachment above bone

Answer

Biologic width (~2mm) is the combined dimension of the junctional epithelium (~1mm) and connective tissue attachment (~1mm) that must be respected when placing restoration margins.

Question 3

During root canal shaping, which concept describes enlarging the canal more at the coronal third to improve irrigation and reduce ledging?

Accepted Answer

Crown-down technique

Answer

The crown-down technique shapes the canal from the orifice downward, removing coronal interferences first to improve irrigant access, reduce apical debris extrusion, and minimize ledging.

Question 4

A healthy sulcus depth is generally considered to be:

Accepted Answer

1–3 mm

Answer

A healthy gingival sulcus typically measures 1–3 mm in depth; depths exceeding 3 mm with attachment loss are considered pathologic periodontal pockets.

Question 5

What is the MOST common cause of endodontic treatment failure?

Accepted Answer

Incomplete removal of infected tissue and inadequate seal

Answer

The most common cause of endodontic failure is inadequate debridement leaving residual infected tissue combined with a poor coronal or apical seal allowing recontamination.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Periodontics and Endodontics 3