Effect of Whitening Toothpastes on Dentin Abrasion: An in Vitro Study

Purpose: To compare the effect of toothbrushing abrasion with hydrated silica-based whitening and regular toothpastes on root dentin using contact profilometry. Materials and Methods: Ninety dentin specimens (4 x 4 x 2 mm) were randomly divided into five experimental groups (n = 18) according to the toothpaste: three whitening (W1, W2 and W3) and two regular toothpastes (R1 and R2) produced by two different manufacturers. Using a brushing machine, each specimen was brushed with a constant load of 300 g for 2500 cycles (4.5 cycles/s). 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. Results: The average value of brushing abrasion in pm (mean +/- SD) was obtained from five consecutive measurements of each specimen: W1 = 8.86 +/- 1.58, W2 = 7.59 +/- 1.04, W3 = 8.27 +/- 2.39, R1= 2.89 1.05 and R2= 2.94 +/- 1.29. There was a significant difference between groups (ANOVA, p<0.0001). Post-hoc Tukey's test for multiple comparisons showed differences between all the whitening and regular toothpastes, but not among the whitening nor among the regular toothpastes. Conclusion: The whitening toothpastes tested can cause more dentin abrasion than the regular ones.