Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 13 4 2021 12 15 Effect of Different Bleaching Methods on Optical Behaviors of CAD/CAM Ceramics 113 118 10.34172/ajdr.2021.22 EN Saeed Nikanjam https://orcid.org/0000-0002-5353-583X Samaneh Abbasi Sara Khazaei https://orcid.org/0000-0001-8589-8611 Journal Article 10.34172/ajdr.2021.22 2021 05 02 2021 06 01 Background: The present study aimed to survey the influence of two different bleaching techniques on changes of color, translucency, and whiteness of the four CAD/CAM materials. Methods: The monolithic blocks of Vita Suprinity, Vita Enamic, IPS e.max CAD, and Katana Zirconia were sectioned to discs with thickness of 2 mm (n=30 / each group). Samples from each type of ceramic were assigned to three subgroups: 1) the 40% hydrogen peroxide for 20 minutes; 2) the 16% carbamide peroxide for three hours/day for 2 weeks; and 3) the control. Then CIELab coordinates of each sample were evaluated before and after the intervention by a spectrophotometer. Final color change (ΔE), Whiteness (ΔWI D), and Translucency Parameter (ΔTP) were calculated. Two-way ANOVA test was adopted to analyze the data (α=0.05). Results: Type of ceramic, bleaching subgroups, and interaction between them had a statistically significant influence on mean values of ΔE, ΔWID. The influence of bleaching subgroup on the mean value of ΔTP was also significant (P<0.001). Conclusions: Carbamide peroxide 16% for three hours/day and for two weeks caused the most considerable changes in final color, whiteness, and translucency of the all tested CAD/CAM materials. Maximum color change and whiteness were detected in the Vita Enamic, which were clinically unacceptable.