The effect of restoration thickness and resin cement shade on the color and translucency of a high-translucency monolithic zirconia

Abstract

Statement of problem. Information regarding the influence of cements and material thickness on the final color of monolithic zirconia restorations is lacking. Purpose. The purpose of this in vitro study was to examine the effect of varying resin cement colors and material thicknesses on the color and translucency of a high-translucency monolithic zirconia and to compare these effects with those reported in similar studies that examined other dental zirconia materials. Material and methods. Katana High Translucent (Kuraray) was used as a monolithic zirconia material. A total of 80 disk specimens (10 mm in diameter) were made in 4 different thicknesses of 0.5 mm, 1 mm, 1.5 mm, and 2 mm (n=20 per thickness). The color of the specimens (Commission Internationale de I'Eclairage [CIE] L*, a*, b* values) before cementation was measured using a spectrophotometer. Specimens within each thickness were further divided into 2 groups: transparent (n=10) and opaque (n=10). A transparent or opaque self-etch adhesive resin cement (Panavia V5) was then applied to each specimen. After cementation, the color was measured again. The translucency parameter (TP) and Delta E were calculated and evaluated with the color measurements by using descriptive statistics, correlation analysis, single specimen t test, 2-way ANOVA, and the Tukey Honestly Significant Difference (HSD) test. Results. Statistically significant (P<.001) changes were found with the increasing thicknesses of the high-translucency zirconia specimens. The TP, L*, and b* values decreased, whereas the a* values increased. In both the transparent and opaque groups, statistically significant (P<.001) increases in L*, a*, and b* values and a significant decrease in TP were found with cementation. The lowest AE value (1.19 for 2 mm) was observed for monolithic zirconia-clear cement. The highest AE value (8.05 for the 0.5 mm) was observed for the monolithic zirconia and opaque cement combination. Conclusions. Material thickness and cement color affected the color and translucency of high-translucent monolithic zirconia, with effects similar to those observed with other monolithic zirconia materials.