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

Effect of a Dentifrice Containing Calcium Glycerophosphate and Fluoride on the pH of Dental Biofilm in Vivo

Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordination for the Improvement of Higher Education Personnel

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.

The dental biofilm pH was measured in vivo with the microtouch method, using a palladium microelectrode + reference electrode. Data represents the mean values of the lowest pH observed each time after the use of sucrose.

measurement of pH obtained as described before. However, this time the biofilm was exposed to the dentifrices for a longer period (14 days).

Inclusion Criteria: to live in a non-fluoridated area to have at least 20 natural teeth signed a consent form agreeing to carefully follow the research instructions Exclusion Criteria: presence of active caries lesions periodontal disease use of antibiotics/medication.