Plaque minerals and dental caries.

Studies to date show that extracellular fluid obtained from resting plaque is highly supersaturated with respect to enamel mineral and that, after one sugar rinse, it rarely becomes unsaturated, even though the pH decreases markedly. This is partly because Ca2+ is released from plaque pools and minimises the change in saturation level, that is, acts as a "saturation buffer". Theoretical considerations, however, suggest that, with repeated pH cycling, calcium and possibly phosphate and fluoride pools in plaque will become depleted, at which time a state of marked undersaturation of plaque fluid will appear when the pH decreases on glycolysis. Such plaque fluid would have a high demineralisation potential. An artificial solid-phase supplement of the ion reservoirs in plaque would be expected to delay the time when plaque fluid becomes unsaturated during multiple pH cycling events, and would be expected to have marked anti-caries effects.