Dental Caries Microbiology — MFDS Part 1 MCQ
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Correct answer: E — Streptococcus mutans
Streptococcus mutans is the best answer. It is strongly associated with caries because it adheres within dental biofilm, ferments dietary carbohydrates to acid and tolerates an acidic environment. Dental caries is nevertheless a polymicrobial, biofilm-mediated disease, so S. mutans should not be described as its sole aetiological agent. Lactobacilli are classically associated more with progression of established lesions than initial colonisation. Actinomyces species are particularly associated with root-surface caries. Porphyromonas gingivalis is a major periodontal pathogen, whereas Streptococcus sanguinis is generally a health-associated early coloniser and may compete with S. mutans.
Reference: Mazurel D, et al. Streptococcus mutans and Caries: A Systematic Review and Meta-Analysis. Journal of Dental Research. 2025;104(6):594-603. https://pubmed.ncbi.nlm.nih.gov/39895020/