Effect of Toothbrushing on Surface Characterization of Ceramic-Polymer Materials

Objectives: The purpose of this study was to examine the effects of toothbrushing on the change in color (delta E*) of extrinsic characterization of ceramic-polymer materials
Methods: Two ceramic-polymer materials (Cerasmart, GC; Enamic, Vita) and one lithium-disilicate material (IPS e-max CAD; Ivoclar Vivadent) were examined. The blocks were polished in a polishing machine (Ecomet 6, Buehler) using various grits of silicon-carbide paper. Each block material was characterized and glazed per manufacturers’ instructions. Specimens were then brushed in a toothpaste slurry using a toothbrush machine (Sabri Dental Enterprises) under a load of 3N at 1 Hz with a soft toothbrush (GUM). CIE - L*a*b* values were recorded using a spectrophotometer (Easyshade, Vita) at baseline and at 3, 6, 9, and 12-year equivalent simulated years of brushing (7,300 strokes/yr). A mean change in color (delta E*) and standard deviation were determined for each group and brushing interval. Data were analyzed with a repeated-measures ANOVA and one-way ANOVAs/Tukey’s (alpha=0.05).
Results: Cerasmart and Enamic had a significantly greater delta E* compared to IPS e.max at each time interval. The delta E* was not significant different between Cerasmart and Enamic except at 3 years. Cerasmart and Enamic had a significant increase in delta E* between each time interval, whereas for IPS e.max, the increase in delta E* was only significant at 9 and 12 years of brushing.
Conclusions: The extrinsic stains on the ceramic-polymer materials may be more susceptible to change from toothbrushing compared to the lithium-disilicate material. However, the change may only be clinically perceptible to the naked eye (delta E* > 2.3) after 12 years of brushing the ceramic-polymer materials.