Effects of salivary fluoride on enamel solubility.

Abstract

The fluoride level of human saliva ranges, according to the data of several authors,'-5 between 0.00 and 0.75 ppm. These values seem to have no relationship to the fluoride content of the water supply. McClure2 3 found a mean value of 0.10 ppm fluoride in human saliva obtained from individuals living in fluoride-low drinking-water areas. In areas where the drinking water contained 1.20-1.80 ppm F, no significant increase in salivary fluoride was found. Data from the Evanston dental caries study4 suggested a salivary fluoride level in the range 0.14-0.35 ppm. A salivary fluoride level of 0.75 ppm has been reported from Hungary.5 The authors reported a tendency for higher fluoride levels in the saliva of caries-resistant individuals and assumed that salivary fluoride values greater than 0.25 ppm might be effective for partial protection against dental caries. Although convincing evidence is lacking, it is the opinion of many workers that only microconcentrations of fluorine may be effective in reducing enamel solubility in newly erupted teeth. The purpose of this study was, therefore, twofold: (1) to determine whether the salivary fluoride level in the rat can be modified by feeding fluoride and, concurrently, what effect this salivary fluoride at different fluoride concentrations has on the solubility of the intact enamel surface; and (2) to determine the effectiveness of human salivary fluoride on enamel solubility.