Effect of Thickness and Abutment Type on Masking of Advanced Lithium Disilicate Ceramics

Objectives: This study aimed to evaluate the masking ability of different thicknesses of advanced lithium disilicate (ALDS) ceramic used for implant-supported crowns compared to conventional lithium disilicate (LDS) and to assess the influence of their combination with various implant abutment materials. Methods: Two types of high-translucency computer-aided design/computer-aided manufacturing (CAD/CAM) glass-ceramics in shade A2 were tested: IPS e.max CAD (LDS) and CEREC Tessera (ALDS). Each material was sectioned into four thicknesses (n = 8 per group). Four implant abutments were evaluated: titanium (Ti), yellow-anodized titanium (TiY), pink-anodized titanium (TiP), and white zirconia (Zir). The translucency parameter (TP₀₀) and color difference (ΔE₀₀) between the glass-ceramic and abutment were calculated using the CIEDE2000 formula. Results: Significant differences were observed between 1.0 mm and 2.5 mm thicknesses in all groups except for ALDS on TiY. Both glass-ceramics on TiY and TiP showed lower ΔE00 values than those on Ti, except for 2.0 mm and 2.5 mm ALDS. Additionally, their ΔE00 values were lower than those on Zir. Clinically acceptable ΔE₀₀ values occurred for 2.5 mm LDS on TiP, 2.0 mm ALDS on TiY and TiP, and 2.5 mm ALDS on TiY and TiP. ALDS demonstrated lower TP₀₀ values than LDS at corresponding thicknesses. Conclusions: Greater restoration thickness and titanium anodization improved color masking. Anodized titanium enhanced the glass-ceramic masking ability. ALDS at 2.0-2.5 mm on TiY or TiP and 2.5 mm LDS on TiP achieved clinically acceptable masking, with ALDS showing lower translucency than LDS.