Effects of three whitening toothpastes on the surface roughness and morphology of a nanohybrid composite resin

The present in vitro study compared the effects of three whitening toothpastes on the surface roughness of a nanohybrid composite resin.

Fifty-five disk-shaped composite resin samples (Opallis) were produced and divided into five groups based on the brushing with toothpastes (n=11): 1. Whitening toothpaste containing blue-covarine (White Now, Signal); 2. Whitening toothpaste containing hydrogen peroxide (Optic White, Colgate); 3. Whitening toothpaste containing abrasive agents (Opalescence, Ultradent); 4. Conventional toothpaste (Max Fresh, Colgate); 5. Control (storage in distilled water). Brushing in all test groups was carried out using a brush testing machine. Changes in surface roughness (Ra) and the surface morphology of composite resin were evaluated using profilometry and electron microscopy, respectively. The data were analyzed with paired-samples t-test, Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests. (α=0.05).

Brushing with different kinds of toothpaste increased the Ra of the composite resin compared to the baseline (p<0.05). There were significant differences in Ra between the groups (P<0.001). The Optic White toothpaste group exhibited higher surface roughness than the conventional toothpaste group (Max Fresh) (P<0.001), with no significant differences from the White Now and Opalescence groups (P=0.065 and P=0.523, respectively).

Hydrogen peroxide-containing whitening toothpastes caused the greatest changes in surface roughness and morphology of the nanohybrid composite resin compared to the conventional toothpaste.