NBDE MCQ 4

Question 1

Which nerve provides sensory innervation to the anterior two-thirds of the tongue?

Accepted Answer

Lingual nerve (branch of CN V3)

Answer

The lingual nerve, a branch of the mandibular division of the trigeminal nerve, carries general somatic afferent (touch, pain, temperature) information from the anterior two-thirds of the tongue.

Question 2

Nitrous oxide exerts its analgesic effect primarily through:

Accepted Answer

NMDA receptor antagonism

Answer

Nitrous oxide produces analgesia mainly by antagonizing NMDA (N-methyl-D-aspartate) glutamate receptors, reducing pain signal transmission in the CNS.

Question 3

Which radiographic technique minimizes distortion and projects teeth at their true length?

Accepted Answer

Paralleling technique

Answer

The paralleling technique places the film parallel to the tooth's long axis with the central ray perpendicular to both, producing minimal geometric distortion.

Question 4

In the formation of dentin, which organic component constitutes approximately 90% of dentin matrix?

Accepted Answer

Type I collagen

Answer

Type I collagen comprises approximately 90% of dentin's organic matrix, providing the scaffold upon which hydroxyapatite crystals are deposited.

Question 5

A patient on warfarin therapy requires a routine extraction. The INR result is 3.8. The appropriate course of action is:

Accepted Answer

Postpone and consult physician to adjust anticoagulation

Answer

An INR of 3.8 is above the safe threshold of 3.5 for dental extractions; elective procedures should be postponed and the physician consulted to adjust dosing.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE MCQ 4