The Effect of Brushing and Aging on the Staining and Smoothness of Resin Composites

To evaluate the staining and smoothness of resin composites undergoing aging in water or red wine and simulated brushing with or without dentifrice.

The resin composites (Z250 microfilled and Z350XT nanofilled) were tested according to aging media (deionized water or red wine) and surface treatment (no brushing, brushed with water, or brushed with dentifrice). Specimens (n = 10) were subjected to three aging cycles (5 days) of continuous immersion in the aging media; each followed by simulated brushing (585 strokes). Color coordinates (CIEL*a*b*) were measured with a spectrophotometer (SP60, EX-Rite) and roughness (Ra) measured with a contact profilometer (Surftest SJ-201P, Mitutoyo), in five time points across the experiment. Surface morphology was analyzed using AFM (SPM-9600, Shimadzu) at the end of the experiment. Data for color change (ΔE₀₀ ) and Ra were analyzed by two-way repeated measures ANOVA and Tukey test (p < 0.05).

Color change was observed for all groups, and it was always greater for Z350. Surface treatment did not influence the ΔE₀₀ values for the groups aged in water. However, brushing decreased ΔE₀₀ for the groups aged in red wine. In general, ΔE₀₀ increased with time. Little to no differences in smoothness were observed with aging and brushing. The surface morphology analyses showed exposed/lost filler particles for brushed Z250. Such observations were not so clear for Z350.

Within the limitations of the present experiment, short-time simulated toothbrushing with soft-bristle toothbrush and low abrasive dentifrice did not increase roughness and reduced staining for both nanofilled and microfilled materials.

Staining and surface degradation of the resin composites was reduced, but not prevented by brushing alone. Thus, minimizing the restoration exposure to staining substances is important for maintaining the aesthetic appearance of the restoration. (J Esthet Restor Dent 29:E44-E55, 2017).