Microtensile Bond Strength of Lithium Disilicate to Zirconia with the CAD-on Technique

Purpose Recently, a novel technique was introduced to combine lithium disilicate and zirconia into one restoration. The purpose of this study was to compare the microtensile bond strength of veneering ceramic to a zirconia core in two techniques: the e.max® CAD‐on technique and the Press‐on technique. Materials and Methods Group A was prepared by veneering sintered zirconia blocks (e.max® ZirCAD) with lithium disilicate blocks (e.max® CAD) using the CAD‐on technique according to manufacturer's instructions. Group B was prepared by taking sintered e.max® ZirCAD blocks and veneering them with fluorapatite glass‐ceramic (e.max® ZirPress) using the Press‐on technique according to manufacturer's instructions. Each block was loaded in a dynamic cyclic loading machine. The blocks were then sectioned into 1 × 1 mm2 beams (n = 43) using a precision saw, thermocycled, and loaded in tension until failure on a universal testing machine. A mean and standard deviation were determined per group. Data were analyzed using an unpaired t‐test (α = 0.05). Results The mean microtensile bond strengths were 44.0 ± 13.8 MPa for the CAD‐on technique and 14.9 ± 8.8 MPa for the Press‐on technique. Significant differences were found between the two groups (p = 2.7E−19). Conclusions The CAD‐on technique (lithium disilicate/zirconia) resulted in greater microtensile bond strength than the Press‐on technique (fluorapatite glass‐ceramic/zirconia).