Abstract: Objective To evaluate the translucency and color characteristics of zirconia with different thicknesses. Method Three brands of high translucency zirconia ceramics Katana? UTML(KU), Lava? Plus(LP), Ceramill? Zolid (CZ) with different thicknesses (0.5、1.0、1.2 and 1.5mm) were prepared(n=5 per group), the CIELab* parameters of the sample were measured using a contact colorimeter and its translucency parameter TP was calculated. Statistical analysis was made between each group of TP values and CIELab* values. Results 1. The TP value of KU ranged from 7.666 to 15.555, LP from 7.500 to 14.916, and CZ from 6.804 to 15.508. The translucency of zirconia ceramics with different thicknesses were significantly different (P<0.05). There was an increase in the TP with a decrease in thickness (P<0.05). At the same thickness, the translucency decreases in order of KU, CZ, and LP. The L* value of KU was significantly different from that of LP and CZ(P<0.05), and its brightness was lower than that of LP and CZ(P<0.05). There were significant differences in a* and b* between KU, LP and CZ (P=0.05). Conclusion The three zirconia ceramics evaluated in this study show a certain degree of translucency. KU has the highest transparency, and the translucency of zirconia ceramics increases with decreasing thickness. The color of KU is closest to the chromaticity of human dentin.

Key words: translucency parameter, translucency, optical property, color, zirconia ceramic