Abrasiveness and Bleaching Level of Toothpastes on Composite Resins: A Quantitative Analysis Using a Novel Brushing Simulator

This study assessed the bleaching and abrasiveness levels of different kinds of toothpaste with various RDA values on nanohybrid and microhybrid composite samples using a novel Press-on Force-Guided brushing simulator. One hundred and forty disc-shaped samples were prepared using two nano-hybrid and three microhybrid composites and divided randomly into four subgroups (n = 7). The samples were immersed in a coffee solution for 144 h and then brushed using R.O.C.S. (Remineralizing Oral Care Systems) brand toothpaste with different RDA values [Sensitive Instant Relief (SIR), Sensation Whitening (SW), and their combination with PRO Polishing (PP) (once a week)] using a brushing simulator for 140, 280 and 560 strokes (140 strokes correspondence to one week of real-time brushing). The level of surface roughness and color change (ΔE) were measured before and after the simulated brushing. Color changes were evaluated in Photoshop CC software through ∆E00* values generated from before and after L, a*, b* parameters on sample photographs taken by a mobile dental photography tool. The surface structure of samples was measured before and after the brushing using a profilometer. The measurements were analyzed in SPSS V23 software by Analysis of Variance and the Bonferroni Test, and the level of significance was set at <0.05. Regarding ΔE values comparisons, there were no significant differences between the toothpastes after 2 weeks of brushing. SW (2.82 ± 1.24), SIR + PP (2.78 ± 0.98), and SW + PP (2.84 ± 1.22) values were found to be similar after one month of brushing (p < 0.007). Regarding surface roughness comparisons between the toothpastes, two-week and one-month brushing values were found to be similar and statistically rougher than the initial values. Using R.O.C.S. PRO Polishing with low-abrasive toothpaste may increase the whitening effect by enhancing color recovery.