Impact of simulated toothbrushing and dentifrice abrasiveness on the surface roughness, gloss, and microhardness of CAD/CAM hybrid restorative materials

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Aim: This study investigated the impact of toothpaste abrasiveness on the surface roughness, gloss, and microhardness of resin composite and CAD/CAM hybrid materials. Methods: A 4x3 factorial design was utilized. The substrate was divided into 4 groups: Vita Enamic Hybrid Ceramic (VE), SHOFU Block HC Hybrid Ceramics (SH), Grandio Blocs CAD/ CAM Nano-Hybrid Resin Block (GB), and dental enamel (ESM). The factor abrasiveness of toothpaste presented 3 levels: Low- 36 (L), Medium-78 (M), and extra-high-175 (EH). Before and after brushing represented the repetition factor. Specimens (n=15 per group) measuring 6mm X 2mm were prepared and submitted to brushing aging. Surface gloss, roughness, and microhardness were evaluated before and after the brushing simulation. Threeway repeated measures ANOVA and the Tukey’s test (p<0.05) were used for statistical analysis. Results: Gloss measurements indicated a significant increase after brushing ESM with the M toothpaste, while GB material significantly reduced gloss overall. The use of EH increased the roughness of the ESM group only. An increase in microhardness was detected using L and M for VE, while a decrease was observed in ESM specimens. Conclusion: The tested protocols influenced the surface gloss, and the roughness was similar in the groups, except in the ESM group. The EH abrasive dentifrice was the only one that did not demonstrate statistical differences for microhardness in brushing protocols for these materials.