Abrasiveness and whitening effect of charcoal-containing whitening toothpastes in permanent teeth.

BACKGROUND: Charcoal toothpastes can whiten teeth through abrasion. The purpose of this study was to determine the level of whitening and abrasiveness of charcoal toothpastes in permanent teeth. MATERIALS AND METHODS: In this in vitro study, 30 premolars were polished, sectioned, mounted, and stored for 5 days in a coffee solution at 37°C. The color and surface profile of the teeth were measured by spectrophotometry and a profilometric device, respectively. The specimens were divided into 3 groups of 10 and were brushed 2000 times (equivalent to 3 times a day for 1.5 months) in a brushing machine using 20 g of each toothpaste (Bencer, Beverly, and Colgate) mixed with 40 ml of distilled water. The color and surface profile were remeasured. Bonferroni test and repeated measures analysis of variance (ANOVA) were used to examine the abrasion. One-way ANOVA was used to assess the whitening. RESULTS: The three toothpastes caused changes in the surface profile (P = 0.0001). ΔE was equal to 3.3 (within the acceptable range) in all groups (95% confidence interval). There was no significant difference in abrasion (P > 0.05) and color change (P = 0.884) among toothpastes. CONCLUSION: The results of this study showed that all the three used toothpastes have the abrasive and whitening effect on the samples significantly. The differences between the toothpastes were not significant.