Microbiology and Pathology Flashcards
7 cards from real NBDE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Microbiology and Pathology flashcards as text
Which hepatitis virus is transmitted parenterally and poses the greatest occupational risk to dental healthcare workers through needlestick injuries?
Answer: Hepatitis B virus (HBV)
HBV has the highest risk of transmission via needlestick (6–30%) compared to HCV (1.8%) or HIV (<0.3%), making vaccination essential for dental workers.
A patient with recurrent herpetic labialis is under stress. Which statement best describes the pathogenesis of the recurrence?
Answer: HSV-1 reactivates from latency in the trigeminal ganglion
HSV-1 establishes latency in the trigeminal ganglion and reactivates due to triggers like stress, UV exposure, or immunosuppression.
An ameloblastoma is best characterized histologically by which pattern?
Answer: Follicular islands with peripheral columnar cells and stellate reticulum
The follicular pattern of ameloblastoma shows islands of odontogenic epithelium with reverse-polarized columnar basal cells and a stellate reticulum core.
Which organism is implicated as the primary etiologic agent of localized aggressive periodontitis (previously juvenile periodontitis)?
Answer: Aggregatibacter actinomycetemcomitans
Aggregatibacter actinomycetemcomitans produces leukotoxin and is the primary pathogen in localized aggressive periodontitis affecting first molars and incisors.
A painless, slowly enlarging radiolucency at the angle of the mandible is found in a 25-year-old. Histology shows a parakeratinized stratified squamous epithelium lining. The diagnosis is:
Answer: Odontogenic keratocyst (OKC)
OKC is characterized by a thin, parakeratinized epithelium with a corrugated surface and high recurrence rate, often associated with Gorlin syndrome.
In the complement system, which component is shared by both the classical and alternative pathways and is essential for membrane attack complex formation?
Answer: C3
C3 is the central convergence point for both pathways; its cleavage to C3b initiates the terminal complement cascade leading to MAC formation.
Which staining technique is used to identify acid-fast organisms such as Mycobacterium tuberculosis in tissue sections?
Answer: Ziehl-Neelsen stain
The Ziehl-Neelsen (carbol fuchsin) stain identifies acid-fast mycobacteria, which retain red dye after acid-alcohol decolorization.