Introduction: The bond between the veneering ceramic and the substructure is important for the long-term survival of the restorations. However, the shear bond strength of heat-pressed ceramic substructures to veneering ceramic materials remains unclear.
Aim of study: This study aimed to evaluate the SBS and mode of failure of two heat-pressed glass ceramic substructures (lithium disilicate and zirconia-reinforced lithium silicate) with their corresponding veneering ceramics.
Material and methods. Thirty glass ceramic disk-shaped specimens fabricated from heat-pressed LDS and ZLS (n = 15) with a diameter of 10mm and a thickness of 3mm. LDS and ZLS specimens were veneered with FLGC and LFP veneering materials, respectively. The veneering material was condensed in a mold and fired on the glass ceramic to form a disk with a diameter of 3mm and a thickness of 2mm. Specimens were subjected to shear force in a universal testing machine at a crosshead speed of 0.5 mm/minute until failure. Failed specimens were examined under an scanning electron microscope to analyze the mode of failure. Data analyzed using independent t-test.
Results. LDS (29.75 MPa) showed a statistically significant higher Shear bond strength than that ZLS (21.96 MPa) (P value