Abstract
Purpose: To evaluate the effect of light-curing through 1.0-mm thickness of two types of ceramics IPS Empress Esthetic (EST) and IPS e.max ZirPress (ZR) on the Degree of conversion (DC) and Knoop microhardness (KHN) of two shades of the base of dual-cure resin cement, with or without the catalyst.Materials and Methods: Resin cement shades A1 and A4 were used. A hi-power LED light cured the cement through 1-mm thickness of EST and ZR ceramic discs. All specimens were cured for 20 s directly on an Attenuated Total Reflectance FTIR plate. The DC was calculated at 100 s. The KHN values were obtained immediately and again after 24-hrs. Five specimens were prepared and tested in each group. The DC and KHN results were analyzed with ANOVA and Fisher's PLSD. Results: The addition of catalyst to cement increased DC and KHN values. Specimens cured through EST had higher DC and KHN values than those cured through ZR (p < 0.0001). Shade A4 had higher DC and KHN compared with shade A1. KHN values increased significantly after 24-hrs compared with immediate values. Conclusion: The Knoop hardness and DC of both shades of resin increased with the addition of the catalyst. To achieve the maximum degree of conversion and hardness for the resin luting cement, the addition of catalyst to the light activated mode is recommended especially of you light activated it through ceramics.