Shear Bond Strength of Porcelain Veneering to Nickel-Chromium, Chromium-Cobalt, Zirconia and Lithium Disilicate

Background and Aim: High chipping rates of the veneering porcelain in zirconia ce-ramic restorations have been reported in many clinical studies. However, information on the bonding behavior of veneering porcelain to zirconia and lithium disilicate frameworks is limited. The purpose of this study was to evaluate the bond-ing strength of porcelain veneering to zirconia, lithium disilicate, nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys. Materials and Methods: In this in vitro experimental study, core specimens were fabricated with 12 mm height and 11 mm diameter, and veneering specimens were fabricated with 7 mm height and 5 mm diameter according to the manufacturer’s in-structions in four groups (n=12) as follows: Group I: Ni-Cr alloy, group II: Co-Cr alloy, group III: lithium disilicate, and group IV: zirconia. The shear bond strength (SBS) test was performed in all samples with a universal testing machine with a crosshead speed of 0.5 mm/min. The fractured samples were examined under a stereomicroscope (×10) to determine the mode of failure. The results were analyzed by one-way ANOVA (P<0.05). Results: Maximum SBS was recorded in group IV (zirconia; 34.6 MPa) followed by groups II (Co-Cr; 30.66 MPa), I (Ni-Cr; 30.58 MPa), and III (lithium disilicate; 20.05 MPa). One-way ANOVA revealed no significant difference between the study groups (P=0.174). Conclusion: The SBS of porcelain veneering to zirconia, lithium disilicate, Ni-Cr, and Co-Cr alloys was not significantly different.