Assessment of the effects of dentifrices on plaque acidogenesis via intra-oral measurement of plaque acids.

Dionex ion chromatography was used for identification and quantification of the plaque acids (formate, lactate, acetate, and propionate) formed in vivo following a sucrose rinse. Consistent with other literature reports, lactate and acetate were the predominant acid species generated by plaque. This micro-analytical technique was used for investigation of the effects of dentifrice formulations containing NaF, xylitol, or NaF/xylitol on plaque acid metabolism. Neither a single nor multiple exposures (three times daily for one week) to the experimental dentifrices significantly altered the profiles of the individual acids or total plaque acidity relative to the placebo dentifrice. The lack of an effect of fluoride and xylitol on plaque acid metabolism is attributed to the variability of dental plaque and the low concentrations of active ingredients reaching the plaque. However, we believe that, with further improvement in sampling technique and study design, this approach may prove useful for the study of the effects of active ingredients (i.e., anticaries agents) on plaque acidogenesis.