Effect of Cement Shades on Final Color of Multilayered Zirconia Ceramic Veneers with Different Thicknesses in tooth triple zones

Abstract

Color matching of the laminate veneers to the adjacent teeth still remains challenging due to the high translucency of the ceramic veneers and visual display of the resin cement through the ceramic material. Objectives: the aim of this study was to evaluate the effect of cement shades on final color of multilayered ultra-translucent zirconia veneers for each layer. Methods: A total of 90 5Y-ZP zirconia discs were prepared at two different thicknesses (0.5 mm and 0.7 mm) (n=45) allocated into five groups according to the shade of the try-in paste and resin cement as follow: Universal, Clear, Brown, White and Opaque. The color of specimens on the substrate without cement, and after application of try-in paste and corresponding resin cement were measured for each layers of specimens using a spectrophotometer. For each specimen, ΔE of (polymerized cement - substrate without cement) and (try-in paste - cement) was calculated. Also, Shear bond strength of each cemented specimens was measured before and after aging by using universal testing machine. Data were analyzed with SPSS 17 software using Multifactor ANOVA test. For the shear bond strength between groups Mann-Whitney test and Kruskal Wallis was used. (p<0.05) Results: The results showed that ΔE values for both try-in paste and resin cement were significantly affected by the resin cement shade and the thickness of ceramic veneer (p<0.05). The results revealed that ΔE values for different layers of ceramic (cervical, body and incisal) were significantly different (p<0.05). Also, significant difference was found in shear bond strength before and after aging between the two groups (p<0.05). Conclusion: The color of the resin cement, ceramic thickness and the different layers of multilayered ceramic had significant effect on the final color of veneers milled from multilayered ultra-translucent zirconia.