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

Purpose: 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. Materials and Methods: 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. ∆E ₀₀ color differences were calculated between polished and glazed specimens (ΔE ₁), between polished specimens and their analogous Vita classical shade tabs as targets (ΔE ₂), and between glazed specimens and the targets (ΔE ₃). The ∆E ₀₀ values were compared with a 50:50% acceptability threshold (∆E ₀₀ = 1.8) to assess color matches. Repeated measures ANOVA, Bonferroni, and 1-sample t-tests were used for data analysis (α = 0.05). Results: Mean ∆E ₀₀ values ranged between 1.11 and 2.74 for ΔE ₁, between 2.69 and 6.78 for ΔE ₂, and between 1.47 and 5.59 for ΔE ₃. The overall mean values were 1.82, 4.66, and 3.63 for ΔE ₁, ΔE ₂, and ΔE ₃, respectively. Ceramic shade, ceramic thickness, and surface treatment significantly affected the CIELab values (p < 0.05). All mean ∆E ₂ and ∆E ₃ values were greater than the threshold (p < 0.05) except for the mean ∆E ₃ for the 1.5- and 2-mm-thick, A3 shade, glazed zirconia in the cervical region (p > 0.05). Conclusions: 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.