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 species of Actinomyces is most frequently implicated in extra-radicular actinomycosis, a cause of refractory periapical pathology?
Answer: Actinomyces israelii
A. israelii is the most common cause of actinomycosis, including periapical actinomycosis, and forms characteristic 'sulfur granules' in tissue.
The Malassez epithelial cell rests in the periodontal ligament are significant in endodontic pathology because they:
Answer: Can proliferate to form the epithelial lining of a radicular cyst
The rests of Malassez can proliferate when stimulated by inflammatory mediators and form the epithelial lining characteristic of radicular cysts.
Which pattern of periapical cyst behavior has been proposed to explain why some cysts do NOT heal after successful root canal treatment?
Answer: True cyst — completely enclosed epithelial cavity independent of the canal
True cysts have a completely enclosed epithelial lining and are self-sustaining independent of the root canal, potentially not resolving with root canal treatment alone.
A patient presents with a draining sinus tract traced to the apex of tooth #30. The most likely microbial etiology of this chronic presentation is:
Answer: Mixed anaerobic consortium dominated by gram-negative anaerobes
Chronic periapical abscesses with sinus tracts typically harbor a mixed anaerobic consortium dominated by gram-negative anaerobes such as Fusobacterium and Prevotella species.
Leukotrienes (LTB4) contribute to periapical pathology primarily by:
Answer: Promoting chemoattraction of neutrophils to the infection site
LTB4 is a potent chemoattractant for neutrophils, driving their migration into periapical tissues during acute inflammatory episodes.
In the context of endodontic microbiology, quorum sensing is best described as:
Answer: Cell-to-cell communication via chemical signals regulating virulence gene expression
Quorum sensing is a chemical signaling system (autoinducers) that allows bacteria to coordinate virulence gene expression based on population density.
Which histological feature differentiates an acute apical abscess from an acute exacerbation of chronic apical periodontitis (phoenix abscess)?
Answer: Presence of fibrous connective tissue and chronic inflammatory cells in the surrounding stroma
A phoenix abscess shows superimposed acute inflammation (neutrophils, pus) on a background of chronic granulomatous tissue with fibrous stroma and chronic inflammatory cells.