Effect of Toothbrushing on Surface Color of Ceramic-polymer Materials: An In Vitro Study

The purpose of this study was to examine the effects of toothbrushing on the change in color of extrinsic characterization of ceramic-polymer materials. Two ceramic-polymer materials (CeraSmart, GC; Enamic, VITA) and one lithium-disilicate material (IPS e.max CAD; Ivoclar Vivadent) were tested. Specimens of each material were prepared, characterized, and glazed per manufacturer's instructions. The treated surface of the blocks were then brushed in a toothpaste slurry with artificial saliva using a toothbrush machine with a soft toothbrush. Commission Internationale de L'Eclairage (CIE) L*a*b* values were recorded with a spectrophotometer at baseline and at 3, 6, 9, and 12 simulated years of brushing (7,300 strokes/year). A mean change in color (Δ *) and standard deviation was determined for each group and brushing interval. Data were analyzed with a two-way repeated measures ANOVA examining the effects of toothbrushing the ceramic materials on Δ * over time (α = 0.05). The difference in the Δ * between CeraSmart and Enamic was significant at 3 years, while the differences between them were not significant at 6, 9, and 12 years of simulated brushing. The Δ * of IPS e.max CAD was significantly lower than CeraSmart and Enamic at all time points (all < 0.0001) except for the comparison with Enamic at 3 years. The extrinsic stains on the ceramic-polymer materials may be more susceptible to change from simulated toothbrushing compared to the lithium-disilicate material. Toothbrushing may change the color of extrinsic characterization of ceramic-polymer materials. However, the change may remain clinically imperceptible to the naked eye (Δ * > 1.0) for nearly 6 equivalent years of brushing.