Effects of repeated home bleaching on the surface roughness of CAD-CAM restoration materials

Aim: This study aimed to investigate the effects of the repeated usage of a home-bleaching agent (16% carbamide peroxide) on the surface roughness of commonly used computer-aided design-computer-aided manufacture (CAD-CAM) restoration materials. Methodology: Five different CAD-CAM restoration materials were used in this study: feldspathic ceramic (Vita Mark II—Group VM II), leucite-reinforced glass ceramic (IPS Empress CAD—Group EMP), lithium disilicate-reinforced glass ceramic (IPS e.max CAD—Group EMAX), polymer infiltrated network hybrid ceramic (Vita Enamic—Group VE), and resin nanoceramic (Lava Ultimate—Group LU). A home-bleaching agent containing 16% carbamide peroxide was applied in three repeated periods (10 days, 20 days, and 30 days of exposure). A surface profilometer was used to determine the roughness average (Ra) values of the specimens. The data obtained were statistically analyzed using repeated measures of the analysis of variance (ANOVA) and Bonferroni post-hoc test at a 5% level of significance. Results: All materials exhibited a rougher surface after the first treatment period (10 days of exposure). The roughness of Group VM II continued to increase for up to 20 days. With the exception of Group LU, all groups exhibited a significantly rougher surface after 30 days of exposure compared to the baseline values (p < 0.05). The greatest variation in surface roughness was observed for the ceramic-based groups (VM II, EMP, and EMAX) rather than the hybrid groups (LU and VE). Conclusion: Patients with ceramic-based CAD-CAM restorations should be careful during home-bleaching treatment, especially when repeated applications are involved. Hybrid materials, particularly Lava Ultimate, seem more resistant to the effects of repeated bleaching cycles than ceramic-based materials.   How to cite this article: Çölgeçen Ö, Köse M. Effects of repeated home bleaching on the surface roughness of CAD-CAM restoration materials. Int Dent Res 2022;12(3):143-8. https://doi.org/10.5577/intdentres.2022.vol12.no3.6   Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.