Effects of Ceramic Shade, Ceramic Thickness, and Surface Treatment on the Color Match of High-Translucency Monolithic Multilayer Zirconia Restorations.

The purpose of this in vitro study was to evaluate the effects of ceramic shade, ceramic thickness, and surface treatment on the color match of high-translucency monolithic multilayer zirconia restorations. Seventy-two high-translucency monolithic multilayer zirconia disk specimens with different shades (A2, A3, B2, and B3) and different thicknesses (1, 1.5, and 2 mm) were fabricated, polished, and glazed. CIELab values were measured with a spectrophotometer in the incisal, middle, and cervical regions before and after glazing. ∆ color differences were calculated between polished and glazed specimens (Δ ), between polished specimens and their analogous Vita classical shade tabs as targets (Δ ), and between glazed specimens and the targets (Δ ). The ∆ values were compared with a 50:50% acceptability threshold (∆  = 1.8) to assess color matches. Repeated measures ANOVA, Bonferroni, and 1-sample -tests were used for data analysis ( = 0.05). Mean ∆ values ranged between 1.11 and 2.74 for Δ , between 2.69 and 6.78 for Δ , and between 1.47 and 5.59 for Δ . The overall mean values were 1.82, 4.66, and 3.63 for Δ , Δ , and Δ , respectively. Ceramic shade, ceramic thickness, and surface treatment significantly affected the CIELab values ( < 0.05). All mean ∆ and ∆ values were greater than the threshold ( < 0.05) except for the mean ∆ for the 1.5- and 2-mm-thick, A3 shade, glazed zirconia in the cervical region ( > 0.05). The color match of high-translucency monolithic multilayer zirconia restorations depends on ceramic shade. Additionally, increased ceramic thicknesses (≥1.5 mm) and glazing can improve the color match of these restorations.