Effect of resin cement shade and tooth-shaded background on the final color and optical properties of high-translucency lithium-based CAD/CAM ceramics

BACKGROUND: This study aimed to evaluate the effects of ceramic composition, resin cement shade, and tooth-shaded background on the optical properties and color differences of high translucent (HT) lithium-based ceramics. METHODS: A total of 192 specimens were prepared from four CAD/CAM ceramics: advanced lithium disilicate, lithium disilicate, and two zirconia-reinforced lithium silicate ceramics. The relative translucency parameter (RTP) and opalescence (OP) were evaluated using a digital spectrophotometer. Specimens were evaluated using two resin cement shades (opaque and translucent) and two tooth-shaded backgrounds (A1 and A3). Color differences (ΔE₀₀) between baseline and after cementation measurements were calculated using the CIEDE2000 formula. Data were analyzed using one-way and three-way ANOVA (p < 0.05). RESULTS: Ceramic material significantly influenced RTP and OP values (p < 0.05). Three-way ANOVA revealed significant main effects of material and cement shade (p < 0.001), as well as a significant material × tooth-shaded background interaction (p = 0.013). Opaque cement resulted in significantly higher color differences than translucent cement across all materials and backgrounds (p < 0.05). Higher ΔE₀₀ values were found on the A3 background. CONCLUSIONS: The final color and optical properties of HT lithium-based ceramics were influenced by ceramic composition and resin cement shade. These findings may help clinicians optimize cement shade and material selection for improved esthetic outcomes.