Root Caries Microbiology — MFDS Part 1 MCQ
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Correct answer: D — Actinomyces species are recognised contributors within a polymicrobial cariogenic biofilm.
Actinomyces species, including A. viscosus and A. naeslundii, are classically associated with root-surface biofilms and can contribute to root-caries development. However, root caries is now understood as a dysbiotic polymicrobial process rather than infection by one predominant organism. Mutans streptococci are frequently associated but are neither exclusive nor invariably present. Porphyromonas gingivalis is principally associated with periodontal dysbiosis, not as the main acidogenic initiator of root caries. Candida albicans may interact with cariogenic bacteria and enhance biofilm virulence, but it is not the usual sole primary cause. Staphylococcus aureus is not a characteristic dominant root-caries organism.
Reference: Ji M et al. The landscape of the microbiome at different stages of root caries. Clinical Oral Investigations. 2025;29:217. https://pubmed.ncbi.nlm.nih.gov/40155488/