Evaluation of the effect of glaze or polish application on color stability on different CAD/CAM ceramic surfaces after orthodontic bonding

The aim of this study is to evaluate the color changes that may occur after orthodontic treatment of CAD/CAM aesthetic ceramic materials in vitro. The CAD/CAM ceramics used in our study are zirconia-reinforced lithium silicate ceramic (VITA SUPRINITY® PC), twenty feldspar ceramics (VITABLOCS® MARK II) and twenty leucite-reinforced feldspar ceramics (GC LRF INITIAL® BLOCK). A total of 60 samples, 20 from each brand, were produced with the size of 12 x 14 x 1.5 mm. The samples were divided into 6 groups (n=10) and after the orthodontic application, glaze was applied to one group of each material and manual polish was applied to the other group. Color measurements were measured with a colorimeter device after the first production, after the brackets and the composite residue was removed with a carbide bur, and after the surface treatments. The Mann-Whitney U test was used for the comparison of ΔE values between groups, and the Kruskal-Wallis test and Dunn-Bonferroni tests were used for multiple comparisons. According to the results of the study, Vita Suprinity showed clinically significant color change after orthodontic applications. Vita Mark II and GC LRF Initial Block showed less color change. When all applications are evaluated separately, Vita Suprinity is the CAD/CAM ceramic with the highest color change and Vita Mark II with the least color change. In addition, the brand of CAD/CAM ceramic, the structure of the material and the applied surface treatment (glaze or polishing) affect the degree of color change of the materials.