 Although the mechanisms of action of fluoride are reasonably understood, the mechanism of calcium phosphate and calcium glycerophosphate CaGP are still a matter of debate. It has been suggested that CaGP increases the phosphorus content in the biofilm and, as a result, the buffering capacity of the biofilm is intensified. The pH levels of the biofilm are maintained above the 5.0-5.5 range. This is above the critical range for enamel demineralization. 