NBDE MCQ 2

Question 1

Which cells are primarily responsible for bone resorption during orthodontic tooth movement?

Accepted Answer

Osteoclasts

Answer

Osteoclasts are multinucleated cells derived from monocyte precursors that resorb bone on the pressure side during orthodontic movement.

Question 2

A patient presents with a periapical abscess. The causative bacteria most commonly involved is:

Accepted Answer

Porphyromonas gingivalis

Answer

Porphyromonas gingivalis is the key pathogen in periapical infections due to its virulence factors including proteases and fimbriae.

Question 3

The mental foramen is most commonly located between which teeth?

Accepted Answer

Mandibular first and second premolars

Answer

The mental foramen is typically positioned between the apices of the mandibular first and second premolars, though location varies among individuals.

Question 4

Which local anesthetic has the longest duration of action for pulpal anesthesia?

Accepted Answer

Bupivacaine 0.5%

Answer

Bupivacaine 0.5% with epinephrine provides the longest pulpal anesthesia duration (90–180 minutes) due to its high protein binding and lipid solubility.

Question 5

Enamel matrix proteins that guide enamel crystal formation are primarily secreted by:

Accepted Answer

Ameloblasts

Answer

Ameloblasts secrete amelogenins, enamelins, and ameloblastins, which organize hydroxyapatite crystal growth during enamelogenesis.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE MCQ 2