NBDE Periodontics 4

Question 1

In guided tissue regeneration (GTR), the membrane barrier functions primarily to:

Accepted Answer

Exclude epithelial and gingival connective tissue cells from the root surface

Answer

GTR membranes create a secluded space that prevents fast-migrating epithelial and connective tissue cells from occupying the defect, allowing slower PDL and bone cells to repopulate.

Question 2

A patient presents with painful erythematous gingiva, interdental necrosis, and a punched-out papilla appearance. The most likely diagnosis is:

Accepted Answer

Necrotizing ulcerative gingivitis (NUG)

Answer

NUG is characterized by the classic triad of pain, interdental necrosis/pseudomembrane, and fetid odor, with punched-out papillae being pathognomonic.

Question 3

Which bone morphology is most favorable for periodontal regeneration using GTR or bone grafts?

Accepted Answer

Narrow three-wall infrabony defect

Answer

Three-wall infrabony defects have the most surrounding bone walls to provide cellular progenitors and structural containment for the graft, yielding the best regenerative outcomes.

Question 4

The primary blood supply to the free gingival graft recipient site derives from which source during initial healing (0–3 days)?

Accepted Answer

Plasmatic diffusion from the recipient bed

Answer

During the first 1–3 days (avascular phase), the graft survives by absorbing plasma directly from the recipient bed via diffusion.

Question 5

Enamel matrix derivative (Emdogain) promotes periodontal regeneration primarily by mimicking which developmental process?

Accepted Answer

Hertwig's epithelial root sheath signaling during cementogenesis

Answer

Emdogain (amelogenin proteins) recapitulates root development signals from Hertwig's root sheath to promote acellular cementum and PDL regeneration.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Periodontics 4