Tooth Decay: Causes, Bacteria, and Prevention Strategies

The Decay Process

Dental caries results from acid demineralization of enamel. The acid is produced by oral bacteria metabolizing dietary carbohydrates, especially sucrose.

Key Caries-Associated Bacteria

• Streptococcus mutans: Primary initiator; produces acid and glucans for biofilm adhesion.
• Lactobacillus species: Aciduric, thrive in low pH; advance lesion progression.
• Bifidobacterium, Scardovia, Actinomyces: Associated with root caries.
• Note: Propionibacterium acnes is primarily cutaneous, not a major caries pathogen.

Biofilm (Plaque) Role

Plaque is a structured biofilm where bacteria concentrate acid against the tooth surface. Frequent sugar intake sustains low pH, preventing remineralization.

Prevention

• Brush twice daily with fluoride toothpaste (1450 ppm)
• Clean interdentally daily (floss, interdental brushes)
• Limit sugar frequency; avoid sticky or acidic snacks
• Fluoride varnish or sealants (professional application)
• Regular dental exams at risk-based intervals
• Consider xylitol or silver diamine fluoride for high-risk individuals

Key Concept

Caries is a dysbiosis-driven, diet-modulated, biofilm-mediated disease—not simply "bacteria eating teeth."