ABE Endodontic Microbiology and Pathology 2

Question 1

Which virulence factor produced by Porphyromonas gingivalis allows it to evade host immune responses in periapical infections?

Accepted Answer

Cysteine proteases (gingipains)

Answer

Gingipains are cysteine proteases that degrade immunoglobulins and complement proteins, enabling P. gingivalis to evade host defenses.

Question 2

In a tooth with symptomatic apical periodontitis, which inflammatory mediator is primarily responsible for sensitizing nociceptors and causing spontaneous pain?

Accepted Answer

Prostaglandin E2 (PGE2)

Answer

PGE2 lowers the pain threshold of nociceptors and is a key mediator of pain in acute apical periodontitis.

Question 3

A periapical granuloma is histologically distinguished from a radicular cyst by the:

Accepted Answer

Absence of an epithelial lining

Answer

A periapical granuloma lacks an epithelial lining, while a radicular cyst has a stratified squamous epithelial lining.

Question 4

Which microorganism is most commonly associated with failed root canal treatment and persistent periapical pathology?

Accepted Answer

Enterococcus faecalis

Answer

E. faecalis is highly resistant to intracanal medicaments and is the species most frequently isolated from failed root canals.

Question 5

The 'phoenix abscess' is best described as:

Accepted Answer

An acute exacerbation of a pre-existing chronic periapical lesion

Answer

A phoenix abscess is an acute inflammatory flare-up superimposed on a chronic periapical lesion, often triggered by instrumentation.

(ABE) American Board of Endodontics Practice Test

(ABE) American Board of Endodontics Practice Test

ABE Endodontic Microbiology and Pathology 2