Endodontic Microbiology and Pathology Flashcards
7 cards from real ABE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Endodontic Microbiology and Pathology flashcards as text
Which virulence factor produced by Porphyromonas gingivalis allows it to evade host immune responses in periapical infections?
Answer: Cysteine proteases (gingipains)
Gingipains are cysteine proteases that degrade immunoglobulins and complement proteins, enabling P. gingivalis to evade host defenses.
In a tooth with symptomatic apical periodontitis, which inflammatory mediator is primarily responsible for sensitizing nociceptors and causing spontaneous pain?
Answer: Prostaglandin E2 (PGE2)
PGE2 lowers the pain threshold of nociceptors and is a key mediator of pain in acute apical periodontitis.
A periapical granuloma is histologically distinguished from a radicular cyst by the:
Answer: Absence of an epithelial lining
A periapical granuloma lacks an epithelial lining, while a radicular cyst has a stratified squamous epithelial lining.
Which microorganism is most commonly associated with failed root canal treatment and persistent periapical pathology?
Answer: Enterococcus faecalis
E. faecalis is highly resistant to intracanal medicaments and is the species most frequently isolated from failed root canals.
The 'phoenix abscess' is best described as:
Answer: An acute exacerbation of a pre-existing chronic periapical lesion
A phoenix abscess is an acute inflammatory flare-up superimposed on a chronic periapical lesion, often triggered by instrumentation.
Biofilm within the root canal system is significant because bacteria in biofilm state exhibit:
Answer: Up to 1000-fold greater resistance to antimicrobials
Biofilm bacteria can be up to 1000 times more resistant to antimicrobials than planktonic (free-floating) bacteria.
Which cell type is the predominant effector in chronic apical periodontitis and is primarily responsible for bone resorption via RANKL signaling?
Answer: T lymphocytes
T lymphocytes, particularly Th1 and Th17 subsets, produce RANKL and inflammatory cytokines that drive osteoclast-mediated bone resorption in chronic periapical lesions.