NBDE MCQ 5

Question 1

Which periodontal fiber group runs parallel to the long axis of the tooth and resists intrusive forces?

Accepted Answer

Apical fibers

Answer

Apical fibers radiate from the apex of the root to the surrounding alveolar bone and resist intrusive (axial) loading forces applied to the tooth.

Question 2

Ranula is a mucous retention or extravasation phenomenon most commonly associated with which salivary gland?

Accepted Answer

Sublingual gland

Answer

Ranulas form in the floor of the mouth primarily from the sublingual gland; plunging ranulas extend through the mylohyoid muscle.

Question 3

Which disinfectant is most effective for sterilization of heat-sensitive dental instruments?

Accepted Answer

Glutaraldehyde 2% (10-hour immersion)

Answer

2% activated glutaraldehyde achieves sterilization after a 10-hour immersion and is one of the few chemical agents capable of destroying all microbial life including spores.

Question 4

Amelogenesis imperfecta affects which dental structure and its inheritance pattern includes:

Accepted Answer

Enamel; X-linked, autosomal dominant, or autosomal recessive

Answer

Amelogenesis imperfecta affects enamel formation and can follow X-linked, autosomal dominant, or autosomal recessive inheritance depending on the gene involved.

Question 5

The zone of coagulation necrosis in thermal injury to pulp tissue, followed by the zone of stasis, is BEST described as:

Accepted Answer

Jackson's burn zones applied to pulp thermal injury

Answer

Jackson's burn model (coagulation, stasis, hyperemia) describes the three concentric zones of tissue injury from thermal trauma, applicable to heat-induced pulp damage.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE MCQ 5