Prevotella intermedia — MFDS Part 1 MCQ
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Correct answer: A — Pregnancy-associated gingivitis and necrotising ulcerative gingivitis
Explanation lettering: C = shown as B · B = shown as C
A is correct. Prevotella intermedia is a black-pigmented, Gram-negative obligate anaerobe associated with periodontal dysbiosis. Increased proportions have been documented during pregnancy alongside exaggerated gingival inflammation; steroid hormones can favour the growth of organisms historically identified as P. intermedia. It is also found within the fusospirochaetal and anaerobic microbiota associated with necrotising ulcerative gingivitis. It is an orange-complex organism rather than a principal cariogenic species. Dental caries is predominantly associated with an acidogenic biofilm, oral candidosis with Candida species, and the conditions in option D with herpes simplex virus. Sialolithiasis and mucous retention cysts are obstructive salivary disorders rather than characteristic P. intermedia infections.
Reference: Emmatty R, Mathew JJ, Kuruvilla J. Comparative evaluation of subgingival plaque microflora in pregnant and non-pregnant women: A clinical and microbiologic study. 2013. https://pubmed.ncbi.nlm.nih.gov/23633772/; Loesche WJ et al. The bacteriology of acute necrotizing ulcerative gingivitis. 1982. https://pubmed.ncbi.nlm.nih.gov/6122728/