The effect of fluoride in the remineralization of enamel caries and caries-like lesions in vitro.

Remineralization occurs naturally during the formation of a carious lesion in human dental enamel and is seen in the form of two of the four classical histological zones of the lesion. Exposure of small lesions to a synthetic calcifying in vitro results in a significant increase in remineralization of the lesion. The degree of remineralization achieved depends upon the presence of fluoride ions in the calcifying fluid and its degree of supersaturation. It appears that only low levels of fluoride are required to trigger the mechanism of remineralization; raising the fluoride level further does not result in a greater degree of remineralization. The calcium ion concentration of the calcifying fluid is critical with respect to determining which components are supersaturated and which in turn determines the degree of remineralization achieved. With levels of 3.0 mM calcium only the superficial region of the lesion is remineralized whereas with a calcium concentration of 1.0 mM, remineralization occurs in depth. It is hoped that studies on remineralization phenomena will provide further insight into the mechanisms of caries formation and be the basis for a more powerful and effective form of caries prevention.