Periodontics · single question
A 28-year-old female with excellent oral hygiene presents with 7-8 mm pocket depths in the upper right quadrant and minimal plaque/calculus. Which bacterial species is most associated with this condition?
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Correct answer: A. Aggregatibacter actinomycetemcomitans
This clinical picture — young patient with excellent oral hygiene but aggressive localized bone loss — is classic for LOCALIZED AGGRESSIVE PERIODONTITIS (formerly localized juvenile periodontitis). Aggregatibacter actinomycetemcomitans (Aa) is the primary pathogen associated with localized aggressive periodontitis. It produces leukotoxin that destroys neutrophils and has multiple virulence factors that allow rapid bone destruction disproportionate to the amount of plaque present.
- A. CORRECT. Aggregatibacter actinomycetemcomitans (Aa) is the keystone pathogen in LOCALIZED AGGRESSIVE PERIODONTITIS. The hallmark is severe localized bone loss (typically first molars and incisors) in young patients with minimal plaque/calculus — exactly as described.
- B. INCORRECT. Prevotella intermedia is associated with pregnancy gingivitis and NUG/NUP — not specifically localized aggressive periodontitis.
- C. INCORRECT. Tannerella forsythia is part of the 'red complex' associated with chronic periodontitis, not specifically localized aggressive periodontitis.
- D. INCORRECT. Porphyromonas gingivalis is associated with CHRONIC generalized periodontitis — it is found in patients with significant plaque/calculus and diffuse disease.