Comparison of the effects of whitening and conventional toothpastes on the wear rate of a composite resin.

Considering the importance of the effect of abrasion on a restoration's durability and the high volume of abrasive materials in whitening toothpastes, it is necessary to evaluate whitening toothpastes to determine the degree of abrasion they cause in composite resins. This in vitro study evaluated the abrasive effect of 3 bleaching toothpastes on Filtek Z250 composite resin. Three whitening toothpastes (Oral-B Pro-Expert Whitening, Signal White Now, and Crest 3D White Arctic Fresh) were studied, and Crest Complete 7 conventional daily toothpaste was used as a control group. Forty disc-shaped composite resin specimens, 7 mm in diameter × 2 mm thick, were polymerized according to the manufacturer's instructions. The specimens were divided into 4 groups of 10 each according to the toothpaste applied. An electronic scale was used to record the weight of each specimen before and after simulated toothbrushing (20,000 cycles to simulate 2 years). The weight loss after toothbrushing was calculated, and data were analyzed using Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). The Kruskal-Wallis test showed that there was a statistically significant difference in the weight loss of the specimens depending on the toothpaste used (P = 0.01). The Mann-Whitney U test indicated that Crest 3D White (P = 0.01) and Signal White Now (P = 0.005) were significantly more abrasive than Crest Complete 7 (control). There was no statistically significant difference in abrasion between Oral-B Pro-Expert Whitening and Crest Complete 7 (P = 0.034). According to the results of this study, whitening toothpastes can increase the amount of composite resin abrasion, and the specific toothpaste used affects the amount of abrasion.