Dental Plaque Biofilms

Teradaj Aticharoenkul

Periodontal disease chronic imflammatory lesions

destruction supporting periodontal tissues

associated with specific microbial complexesin subgingival biofilms

Bacterial species Actinobacillus actinomycetemcomitans

Actinomyces odonlyticus Actinomyces naeslundii Capnocytophaga gingivalis

Fusobacterium nucleatum

Bacterial species Streptococcus mitis Eubacterium nodatum Propionibacterium acres Porphyromonas gingivalis

Treponema denticola

Treponema denticola Gram negative oral spirochete predominant of human periodontal disease

infection and inflammation of gingiva

occurs in 80% of the adult population

lives and can evolve to severe

Treponema denticola

refractory periodontitis acute necrotizing gingivitis

bone resorption and tooth loss

Biofilm communities Comprises : bacterial microcolonies,extracellular slime layer, fluid channels and

primitive communication system

Biofilm communities• bacteria attach to a surface

• mushroom-shaped microcolonies

• different microcolonies may contain different combinations of bacterial species

• the slime layer protects the bacterial microcolonies from antibiotics,antimicrobials,and host defense mechanisms

Biofilm communities

• bacteria in the center of amicrocolony may live in a strict anaerobic environment

• while other bacteria at the edges of the fluid channels may live in an aerobic environment

Biofilm communities• the biofilm structure provides

a range of customized living environments (with differing pHs, nutrient availability, and oxygen)

• within which bacteria withdifferent physiological needs can survive

• fluid channels penetrates the extracellular slime layer

Biofilm communities

• fluid channels provide nutrients and oxygen for thebacterial micro colonies and facilitate movement ofbacterial metabolites, wasteproducts, and enzymes within the biofilm structure

• Each bacterial microcolony uses chemical signals to create a primitivecommunication system used to communicate with other bacterial microcolonies

Phases of plaque formation

Phases of plaque formation

The pattern of biofilm development

• absorption of salivary proteins and glycoproteins

• some bacterial molecules, to the tooth surface (the acquired pellicle)

• long-range (>5Onm), non-specific interaction of microbial cell surfaces with the acquired pellicle

• shorter-range (10-20nm) interactions

• result in reversible adhesion to the surface.

• irreversible adhesion • adhesins on the cell surface and

receptors in the acquired pellicle.

• secondary or late-colonisers attach to primary colonisers (coaggregation)

• Cell division of the attached cells to produce confluent growth, and a bioflim.