Figure 13. Role of saliva in the various calcium phosphate reactions that occur at the tooth-plaque-saliva interface. Saliva provides calcium and phosphate (i) as ions and (ii) as part of a calcium phosphate carbohydrate protein complex (i.e., salivary precipitin). Both help provide a continuous supply of calcium and phosphate for plaque and tooth mineralization. At acidic pH (high H⁺ concentration), movement of calcium and phosphate from tooth and plaque to saliva is favored, whereas at alkaline pH, the reverse is favored. The calcium and phosphate ions produced in the plaque from plaque calcium phosphate during acid formation are in a position to suppress or retard tooth solubilization by mass action as well as to facilitate tooth remineralization (from Kleinberg et al., 1983).