Effect of fluoride varnish supplemented with sodium trimetaphosphate on enamel erosion and abrasion: An in situ/ex vivo study

Objective: To evaluate the effect of fluoride (F) varnishes supplemented or not with sodium trimetaphosphate (TMP) on enamel erosive wear followed or not by abrasion in situ. Methods: Ten volunteers were selected and randomly divided into four groups, according to the varnishes tested: placebo (no F or TMP), 5% NaF (positive control), 2.5% NaF and 2.5% NaF/5% TMP. Enamel blocks (n = 4) were mounted in palatal devices and received an application of each test varnish, following a double-blind, crossover protocol. After 6 h, varnishes were completely removed and the blocks were subjected to erosive challenges by ex vivo immersion in citric acid (5 min, 4x/dia, 5 days). Following, half of the blocks were subjected to abrasion by brushing with a placebo dentifrice slurry for 15 s. Enamel wear (mu m), surface hardness (SHf) and cross-sectional hardness (Delta KHN) were assessed after each experimental period. Results were analyzed by ANOVA, Student-Newman-Keuls's test and Pearson correlation coefficient (p < 0.05). Results: The fluoride varnish supplemented with TMP promoted significantly lower wear and DKHN when compared to the other groups after erosive challenges, followed or not by abrasion (p < 0.05). As for (SHf) the fluoride varnish supplemented with TMP promoted similar results to the 5% NaF product, being significantly higher than the remaining groups after erosive and erosive + abrasive challenges (p < 0.05). Conclusion: TMP significantly enhanced the effects of F on enamel wear after erosive challenges, followed or not by abrasion. (C) 2013 Elsevier Ltd. All rights reserved.