What bacteria colonize cavities (tooth decay)?

Bacteria That Colonize Dental Cavities

The primary bacteria responsible for dental cavities are Streptococcus mutans and Streptococcus sobrinus, which are the principal bacteria implicated in the initiation of dental caries in humans. 1

Primary Cariogenic Bacteria

• Mutans streptococci:

  • Streptococcus mutans - The most well-established and primary cariogenic bacteria 1, 2
  • Streptococcus sobrinus - Another important member of the mutans streptococci group 1

• Acquisition and colonization:

  • Infants acquire mutans streptococci primarily from their mothers 1
  • Initial acquisition typically occurs during a "window of infectivity" (19-31 months of age) 1
  • Colonization requires the presence of hard, non-desquamating surfaces (teeth) 1

Other Bacteria Associated with Dental Caries

• Acid-producing bacteria:

  • Lactobacillus species (including Lactobacillus sakei) 3
  • Leuconostoc mesenteroides 3
  • Streptococcus salivarius 3
  • Streptococcus anginosus 3

• Oral flora that may contribute to caries:

  • Prevotella species 1, 4
  • Actinomyces species 1, 4
  • Fusobacterium species 4
  • Peptostreptococcus species 4

Mechanism of Cavity Formation

1. Initial colonization:

   • Mutans streptococci attach to tooth surfaces and form biofilms (dental plaque) 1
   • Dental plaque biofilm formation begins soon after a tooth surface is cleaned 1

2. Acidogenic environment:

   • These bacteria metabolize fermentable carbohydrates (especially sucrose) 1
   • This produces an acidogenic plaque environment that lowers oral pH 1
   • The acidic environment promotes demineralization of dental enamel 1
   • Eventually leads to caries formation 1

3. Biofilm maturation:

   • Without proper oral hygiene, biofilm thickens and evolves to include more pathogenic bacteria 1
   • The biofilm largely isolates bacteria from the immune system 1

Risk Factors for Bacterial Colonization

• Dietary factors:

  • Frequent consumption of fermentable carbohydrates 1
  • Prolonged bottle or breast feeding in infants (provides substrate for bacterial proliferation) 1

• Oral hygiene:

  • Poor oral hygiene increases bacterial load 4
  • Gingival inflammation allows bacteria easier access to bloodstream 1

• Family factors:

  • Maternal caries (source of transmission) 1
  • Sibling caries 1

Prevention of Bacterial Colonization

• Oral hygiene:

  • Regular and thorough brushing with fluoride toothpaste 4
  • Daily flossing 4
  • Professional dental cleaning 4

• Fluoride use:

  • Topical and systemic fluoride increases resistance to acid demineralization 1
  • Fluoride accumulates in plaque where it decreases microbial acid production 1

• Dietary modifications:

  • Limiting intake frequency of foods and liquids that promote acid production 1
  • Avoiding prolonged exposure to fermentable carbohydrates 1

• Early intervention:

  • Professional intervention before the established window of infectivity 1
  • Parental education about proper oral health care for infants 1

Dental caries is fundamentally an infectious and transmissible disease caused by an imbalance of the indigenous oral biota rather than an exogenous pathogen 5. Understanding the bacterial colonization process is essential for implementing effective prevention and treatment strategies to maintain oral health.