Chemical Composition

Plaque in situ is composed of almost 80% water and bulk of the solid phase is comprised of protein. Immunoglobulins such as IgA, IgG and IgM have been detected in the dental plaque. The protein composition of dental plaque appears to be little influenced by the composition of the diet.

Plaque contains carbohydrates and there is little doubt that the amount of carbohydrate in plaque is influenced by the composition of the diet. The type of carbohydrates formed is also determined by the diet. The bulk of the polysaccharide in plaque is also determined by the diet. Most of the polysaccharide in plaque is extracellular. The two common and important extra-cellular polysaccharides are glucan and tructan. The synthesis of polysaccharide probably represents an attempt by microorganisms to store sources of energy as fructans can be readily metabolized by plaque bacteria. The glucans help in colonization of bacteria on tooth surfaces.

Plaque contains inorganic materials of which Ca, P04and F are of great importance. The level of Ca and P04in plaque play a crucial role in the pathogenesis of dental caries and formation of dental calculus. Significantly higher levels of Ca and P04 are found in the plaque from areas where calculus forms most frequently. Whereas lower levels of Ca and P04 are generally associated with carious areas in the oral cavity.

Fluoride is cariostatic. Therefore, the level of fluoride in plaque can significantly influence the cariogenic activity of the micro-organisms and the stability of the tooth enamel. The fluoride in plaque is not derived from tooth enamel and is concentrated from saliva, gingival fluid and drinking water.

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