Avaliação in vitro do efeito da escovação com dentifrícios clareadores sobre a superfície dentinária

Abstract

Toothbrushing abrasion has an important role in the etiology of dentine hypersensitivity. The abrasion may be related to the abrasivity of the toothpaste. The aim of this study was to compare by mechanical profilometry the effect of toothbrushing abrasion with whitening and regular toothpastes on root dentine. Ninety dentine specimens (4x4x2 mm) were randomly divided into five experimental groups (n=18) according to the toothpaste: three whitening (W1, W2 and W3) and two regular toothpastes (C1 and C2), produced by two different manufacturers. Using a brushing machine, each specimen was brushed with constant load of 300g for 2500 cycles (4.5 cycles/second). The toothpastes were diluted at a ratio of 1:3 w/w (dentifrice/distilled water). The brush diamond tip of the profilometer moved at a constant speed of 0.05 mm/s with a force of 0.7 mN. The average reading value of brushing abrasion (μm; mean ± standard deviation) was obtained from five consecutive measurements of each specimen: W1 = 8.86 ± 1.58, W2 = 8.27 ± 2.39, W3 = 7.59 ± 1.04, R1 = 2.94 ± 1.29 and R2 = 2.89 ± 1.05. There was a significant difference between groups (ANOVA - p<0.0001). Post-hoc Tukey test for multiple comparison showed differences between all the whitening toothpastes and the regular ones, but not among the whitening or the regular against each other. Whitening toothpastes can cause more dentine abrasion than the regular ones.