Effect of experimental xylitol and fluoride-containing dentifrices on enamel erosion with or without abrasion in vitro.

This in vitro study aimed to analyze the effect of including xylitol into a fluoridated dentifrice to provide protection against enamel erosion with or without abrasion. Bovine enamel specimens were subjected to erosion or erosion plus abrasion (7 days) and the treatment with the following dentifrices: 10% xylitol; 10% xylitol plus 1,030 ppm F (NaF); 1,030 ppm F; and placebo. The erosive challenges were performed 4 times a day (2 min at a time). The specimens were exposed to the slurries of the dentifrices 2 times daily (15 s at a time). Half of the specimens per group were additionally abraded using an electrical toothbrush (F = 1.5 N). Between the challenges, the specimens were remineralized by artificial saliva. Enamel loss was measured profilometrically (µm). The data were statistically analyzed by two-way ANOVA and Bonferroni's post-hoc test (P < 0.05). Ten percent xylitol plus F and F dentifrices significantly reduced enamel erosion compared to placebo and xylitol dentifrices. On the other hand, all dentifrices presented a significant potential to protect against enamel erosion plus abrasion compared to placebo, with 10% xylitol plus F showing the best results. Based on this result, the inclusion of 10% xylitol increased the effect of the fluoridated dentifrice against enamel erosion plus abrasion in vitro. In situ or clinical studies are needed to confirm the data.

Effects of experimental xylitol varnishes and solutions on bovine enamel erosion in vitro.

This in vitro study aimed to analyze the effects of application of xylitol varnishes and solutions to protect against enamel erosion. Twelve bovine enamel specimens were pre-treated with 5% NaF-Duraphat varnish, 10% xylitol varnish, 20% xylitol varnish, placebo varnish, 5% NaF solution, 10% xylitol solution or 20% xylitol solution. The varnishes and solutions were applied for 6 h and 1 min, respectively. Controls remained untreated (n = 12). Specimens were then subjected to erosive demineralization (Coca-Cola, 4 × 90 s/d) and remineralization (artificial saliva, 2 h) cycling for 10 days. After 5 days, the varnishes and solutions were reapplied. After reapplication, two specimens per group were analyzed by SEM. Enamel loss was measured profilometrically after the 5th and 10th days. Data were then analyzed statistically by ANOVA and Tukey's post-hoc test (n = 10, P < 0.05). After the 5th day, all varnishes and 20% xylitol solution significantly reduced the enamel loss when compared to the placebo varnish/control. After 10 days of erosive pH cycling, both xylitol varnishes and solutions significantly reduced the enamel erosion when compared with the control. However, 10% xylitol solution produced a smooth layer on eroded enamel and significantly reduced the enamel erosion when compared to the placebo varnish/control. Xylitol thus appears to be a good option to partially reduce enamel erosion.