Effect of whitening toothpaste on superficial roughness of composite resin.

This study sought to evaluate the effect of different toothpastes with whitening action on the average surface roughness (Ra) of a microhybrid composite resin. Twenty-five specimens of composite resin were prepared and distributed randomly among 5 experimental groups (n = 5). Groups 1-3 were treated with whitening toothpastes: Close-up Extra Whitening, Colgate Ultra White, and Colgate Total 12 Whitening. Group 4 was a negative control group (with samples brushed with deionized water), and Group 5 was a positive control group (with samples brushed using a non-whitening toothpaste). A profilometer was used to determine Ra before and after brushing. A simulated brushing machine was used for all groups, providing horizontal back and forth movement with an amplitude of 3.8 cm applying an axial load of 200 g and a speed of 356 rpm, totaling 20,000 cycles. To determine the Ra in each specimen, 6 readings were taken at various positions before and after brushing. The results were submitted to variance analyses and Tukey's test. (P < 0.05). Groups 1, 2, 3, and 5 demonstrated statistically significant differences between initial and final averages. Based on these results, it was determined that brushing with toothpaste, regardless of formulation, significantly increased the Ra of the resin composite evaluated in this study.