Shear bond strength between Ni-Cr alloy bonded to a ceramic substrate

doi: 10.1111/j.1741‐2358.2011.00585.x Shear bond strength between Ni‐Cr alloy bonded to a ceramic substrate Introduction: The aim of this study was to evaluate the shear bond strength between a Ni‐Cr alloy and a ceramic system submitted or not to thermocycling. Materials and methods: Forty‐eight cylinder blocks of Ni‐Cr with 3.0 mm diameter by 4.0 mm hight and 48 disc‐shaped specimens (7.0 mm in diameter by 2.0 mm thick) composed of ceramic were prepared. The Ni‐Cr cylinder blocks were randomised in two groups of 24 specimens each. One group was submitted to air‐particle abrasion (sandblasting) with 50 μm Al₂O₃ (0.4–0.7 MPa) during 20 s, and the other group was submitted to mechanical retentions with carbide burrs. Each group was subdivided into other two groups (n = 12), submitted or not to thermocycling (500 cycles, 5–55°C). The cylinder blocks were bonded to the disc‐shaped ceramic specimens under 10 N of load. The shear bond strengths (MPa) were measured using a universal testing machine at a cross head speed of 0.5 mm/min and 200 kgf of load. The data were submitted to statistical analysis (anova and Tukey’s test). Results: The air‐particle abrasion group exhibited significantly higher shear bond strength when compared to drilled group (p < 0.05). Conclusions: Thermocycling decreased significantly the bond strengths for all groups tested.