Effect of CAD-CAM block material and thickness on the translucency parameter and polymerization of light-cured resin cement

PURPOSE: This study assessed the association of computer-aided design-computer-aided manufacturing (CAD-CAM) block material and thickness with the translucency parameter and polymerization of a light-cured resin cement. METHODS: Specimens were prepared from CAD-CAM blocks (Lava Ultimate, IPS Empress CAD, Celtra Duo) with thicknesses of 0.5, 1, and 2 mm (n = 10 each). The translucency parameter (TP) of the blocks was calculated with a spectrophotometer. A total of 100 resin cement specimens were prepared from Calibra Veneer, and the microhardness of the resin cement was measured with a Vickers microhardness device. RESULTS: In all CAD-CAM blocks, TP decreased as thickness increased (P < 0.05). Microhardness values for the top surface were lower than that of the control group for all groups except the LU 0.5 mm group (P < 0.05). Microhardness values for the bottom surface were lower than that of the control group in all groups (P < 0.05). In addition, microhardness was lower immediately after polymerization than at 24 h after polymerization in all groups (P < 0.05). CONCLUSION: The microhardness of a light-cured resin cement varied in relation to the material and thickness of the CAD-CAM block and was higher at 24 h after polymerization.