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

Lipopolysaccharide (LPS)

Answer

Hydrogen peroxide

Answer

Bacteriocins

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

Interleukin-10

Answer

Transforming growth factor-beta

Answer

Interleukin-4

Question 3

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

Accepted Answer

Absence of an epithelial lining

Answer

Presence of plasma cells

Answer

Presence of Russell bodies

Answer

Absence of macrophages

Question 4

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

Accepted Answer

Enterococcus faecalis

Answer

Fusobacterium nucleatum

Answer

Treponema denticola

Answer

Prevotella intermedia

Question 5

The 'phoenix abscess' is best described as:

Accepted Answer

An acute exacerbation of a pre-existing chronic periapical lesion

Answer

A primary acute apical abscess with no prior infection

Answer

A sterile abscess caused by chemical irritation

Answer

A periapical cyst that becomes secondarily infected

Question 6

Biofilm within the root canal system is significant because bacteria in biofilm state exhibit:

Accepted Answer

Up to 1000-fold greater resistance to antimicrobials

Answer

Increased susceptibility to antibiotics compared to planktonic forms

Answer

Reduced virulence due to nutrient limitation

Answer

Decreased ability to communicate via quorum sensing

Question 7

Which cell type is the predominant effector in chronic apical periodontitis and is primarily responsible for bone resorption via RANKL signaling?

Accepted Answer

T lymphocytes

Answer

Neutrophils

Answer

Mast cells

Answer

Natural killer cells