Dental Plaque Biofilm

Dental Plaque Biofilm Definition

• Dental plaque is a biofilm that forms on teeth or other solid surfaces in the mouth.
• It's a soft deposit containing salivary elements, desquamated cells, debris, and microorganisms embedded in an extracellular matrix.

Types of Dental Plaque

• Supragingival: Forms above the gum line.
• Subgingival: Forms below the gum line.
• Tooth-attached: Adheres directly to the tooth surface.
• Unattached: Free-floating bacteria.
• Tissue-attached: Attached to soft tissues.

Biofilm Formation

• Biofilm formation involves four phases:
  • Initial attachment: Free-floating bacteria attach to the pellicle.
  • Initial colonization: New bacteria join the initial colonizers.
  • Secondary colonization: Extracellular slime layer forms, allowing anaerobic bacteria to colonize.
  • Mature biofilm: Formation of mushroom-shaped colonies with fluid channels for nutrient and waste exchange.

Initial Attachment

• Bacteria attach to the pellicle, a thin coating of salivary proteins.
• The pellicle forms within hours of cleaning and acts as a protective barrier for enamel.
• The pellicle also provides a surface for bacteria to adhere to.

Primary Colonizers

• The first bacteria to colonize the tooth surface are called primary colonizers.
• These include:
  • Streptococcus sanguis
  • Streptococcus mutans
  • Streptococcus salivarius

Secondary Colonization & Extracellular Slime Layer

• Secondary colonizers typically attach to primary colonizers through coaggregation.
• The extracellular slime layer is produced by the bacteria to protect the colony.
• It provides a barrier against the immune system and allows for communication between bacteria.

Mature Biofilm

• Mature biofilms are characterized by mushroom-shaped colonies.
• Fluid channels within the biofilm allow for nutrient intake, waste removal, and communication.

Composition of Dental Plaque Biofilm

• Dental plaque biofilm is composed of:
  • Organic components: Polysaccharides, proteins, glycoproteins, lipids.
  • Inorganic components: Calcium, sodium, phosphorus, potassium.
  • Microorganisms: Both aerobic and anaerobic bacteria.
  • Extracellular matrix: The matrix provides structure and protection.

Bacteria Associated with Periodontal Disease

• Bacteria known to contribute to periodontal disease include:
  • Aggregatibacter actinomycetemcomitans
  • Porphyromonas gingivalis
  • Treponema denticola

Bacteria Associated with Caries

• Caries-associated bacteria include:
  • Streptococcus mutans
  • Lactobacilli

Bacterial Virulence Factors

• Biofilm virulence factors are mechanisms allowing for colonization, invasion, and tissue damage.
• These can be structural characteristics of bacteria or substances they produce.

Removal of Dental Plaque

• Plaque removal is essential for maintaining oral health.
• Physical methods can be used to remove plaque:
  • Toothbrushing: Disrupts the biofilm with friction.
  • Flossing: Removes plaque from between teeth.
  • Professional cleaning: Provides thorough plaque removal.

Dental Plaque & Disease

• Plaque accumulation is the primary cause of dental caries and periodontal disease.
• Maintaining good oral hygiene is crucial for preventing these conditions.