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

Abstract

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 6h, varnishes were completely removed and the blocks were subjected to erosive challenges by ex vivo immersion in citric acid (5 min, 4×/dia, 5 days). Following, half of the blocks were subjected to abrasion by brushing with a placebo dentifrice slurry for 15s. Enamel wear (μm), surface hardness (SHf) and cross-sectional hardness (ΔKHN) 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 ΔKHN 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.

Keywords: Demineralization; Dental wear; Enamel; Erosion; Fluoride varnish; Toothbrush abrasion.