Translucency and Strength of Lithium Disilicate for Computer-Aided Design and Manufacturing at Different Thermal Temperatures and Thicknesses: An In Vitro Study

To manufacture dental restorations composed of lithium disilicate (LD) through the computer-aided design and manufacturing (CAD/CAM) process, thermal refinement is an essential process that can affect the optical and mechanical properties of ceramics. In this study, we aimed to evaluate the translucency and flexural strength of lithium disilicate glass-ceramic for CAD/CAM using different thermal refinement schedules and thicknesses by measuring the total transmission of light through the specimen and calculating the peak load of the specimen until fracture in a piston-on-three-ball test, respectively. The results showed that a lower translucency was exhibited in thicker specimens, and the flexural strength decreased in the order of 1.0, 0.5, and 2.0 mm ( < 0.05). The lithium disilicates thermally refined at a heat of 820 degrees were shown to have the highest biaxial flexural strength ( < 0.05). These findings suggest that it is possible to adjust transparency and strength according to the clinical situation by choosing an appropriate thickness and thermal refinement process.