Effect of Calcium Glycerophosphate (CaGP) - Fluoride Dentifrice on Dental Biofilm pH

Overview

The aim of this study was to investigate the buffering effect of a calcium glycerophosphate-fluoride (CaGP-F) dentifrice on in vivo dental biofilm after a cariogenic challenge and evaluate its probable 12-hour protective effect. Twelve young adults took part in this randomized, double blind, 14-day 4-phase crossover study. Between each phase, the volunteers had a 1-week wash-out period. Coded dentifrices were randomly assigned to the volunteers: A) no F and no CaGP; B) CaGP-only (0.13%); C) F-only (1500 ppm (ppm= parts per million of fluoride which is equivalent to mg/kg)); D) CaGP-F (0.13%, 1500 ppm, respectively). The pH measurements were taken from a single-site using a microelectrode, with salt bridge established by a 1M KCl (one molar potassium chloride) solution with a reference electrode. pH measurements were taken at 0 (baseline), 1, 7, 14 and 21 min (minutes) after a cariogenic challenge (10% w/v sucrose solution, %w/v = percent weight per volume). Four sets of measurements were carried out: (D0BS) before test dentifrice usage; (D01min) 1-min after test dentifrice usage; and (D712h) 7 days and (D1412h) 14 days using the test dentifrice, 12 hours (h)after brushing. Stephen curves and mean AUC (area under the curve) were obtained.

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.