Comparative Evaluation of the Optical Properties of CAD-CAM Zirconia Materials: An In Vitro Study

The aim of this in vitro study was to compare the relative translucency parameter (RTP), contrast ratio (CR), and opalescence parameter (OP) of selected commercial translucent CAD-CAM zirconia materials. Three Computer-Aided Design – Computer-Aided Manufacturing (CAD-CAM) zirconia materials were evaluated: Katana UTML, InCoris TZI C, and Cercon XT. Thirty-six A2-shade specimens with dimensions of 10 × 12 mm and a final thickness of 1.00 ± 0.05 mm were prepared. Color coordinates were measured on standardized black and white backgrounds using a digital spectrophotometer. RTP was calculated using the CIEDE2000 formula, CR was determined from reflectance values, and OP was calculated from differences in a* and b* coordinates. The data were analyzed using one-way analysis of variance followed by the Bonferroni post hoc test. Significant differences were found among the materials for RTP, CR, and OP. Katana UTML showed significantly higher RTP and lower CR values than InCoris TZI C and Cercon XT. However, Katana UTML showed significantly lower OP values. These findings indicate that translucency and opalescence do not necessarily change in parallel. RTP, CR, and OP should therefore be considered together when selecting zirconia materials for esthetic restorations.