Enamel fluoride uptake of an anticaries/antigingivitis mouthrinse

Objective: The efficacy of an experimental anticaries/antigingivitis rinse containing fluoride and essential oils in promoting fluoride uptake into demineralized enamel was evaluated in vitro. This mouthrinse contains 0.022% sodium fluoride (NaF, pH 4.2) as the fluoride source, and 4 essential oils (Thymol, Menthol, Eucalyptol, and Methyl Salicylate) as antiplaque/antigingivitis active ingredients. A fluoride-free placebo and a clinically proven reference rinse containing the same fluoride source (pH 7.0) were included as controls. Methods: The test procedure was similar to the one identified as Procedure 40 in the FDA monograph except the following: 1) the lesion was formed using a partially saturated solution containing lactic acid and Carbopol, 2) the micro drill method was used for sampling the enamel, and 3) statistical success criteria - a test formulation is considered to be effective if it is "at least as good as" the positive control. Three groups of 20 enamel specimens were pre-demineralized, treated with assigned rinses, and then analyzed for fluoride content. Analyses of variance were used to compare inter-group means. Results: Compared with the fluoride-free vehicle control, the experimental rinse and positive control produced statistically significant fluoride uptake of 854 ppm and 227 ppm respectively (p<0.001). Compared with the clinically tested positive control rinse, the experimental rinse produced statistically significantly more fluoride uptake (p<0.001). Conclusions: The results of this study show that 1) both the experimental rinse containing essential oils and positive control rinse are statistically significantly effective in promoting fluoride uptake in vitro. 2) the fluoride bio-availability of the experimental rinse is not adversely affected with the addition of essential oils.