Micro & Immunology · single question
Coronal caries are most commonly associated with which bacterial species?
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Correct answer: A. Streptococcus mutans
Streptococcus mutans is the primary pathogen in coronal caries initiation. It produces glucosyltransferases that synthesize insoluble glucans for biofilm adhesion, and generates lactic acid from fermentable carbohydrates. Lactobacillus species are associated with caries progression (dentinal caries). Actinomyces viscosus is the primary pathogen in root surface caries. Knowing this distinction is frequently tested.
- A. ✅ CORRECT – S. mutans initiates coronal caries through acid production, biofilm adhesion, and acid tolerance.
- B. ❌ Lactobacillus species are secondary colonizers that drive dentinal caries progression, not the primary initiators.
- C. ❌ Actinomyces viscosus is the primary organism in root surface (cervical) caries, not coronal caries.
- D. ❌ P. gingivalis is a key periodontal pathogen (keystone pathogen) — not associated with caries.
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