Evaluation of the Effect of Different Finishing and Polishing Procedures on the Color Change and Translucency Properties of Monolithic CAD/CAM Ceramic

Aim: The purpose of this study was to compare the effects of different finishing and polishing procedures for monolithic CAD/CAM ceramics on their optical properties after ultraviolet (UV) aging. Material and Methods: A zirconia-reinforced lithium silicate ceramic (Vita Suprinity) with a thickness of 1.5 mm was selected for this study. A total of 42 samples were prepared and divided randomly into six groups on the basis of the finishing–polishing technique used: disc, polishing paste and glazing or combinations (n=7). Color change measurements of the samples were performed on a gray background before and after UV aging. The translucency values on white and black backgrounds were calculated after UV aging according to the CIEDE2000 formula. The Kruskal‒Wallis H test and post hoc Dunn test were used for the statistical analysis (P<0.05). Results: The effects of finishing–polishing procedures were statistically significant in terms of color change and translucency (P<0.001). The highest color change was found in the crystallized samples. The samples polished with polishing paste after crystallization and glazing exhibited the lowest color change. The lowest translucency was presented in the samples that just crystallized. The highest translucency was presented in ceramics crystallized with glaze, which was significantly different from that in those crystallized, crystallized+polished with discs, and crystallized+polished with polishing paste ceramics (P<0.001). Conclusion: Finishing ceramic restorations is an important step for long-term clinical use. Glazing or mechanical polishing of zirconia-reinforced lithium silicate ceramics produces similar results in terms of optical properties. Crystallization with glazing together can be used for quick and reliable finishing.