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Background/purpose: Air-particle abrasion process used to increase surface roughness in order to increase metal-ceramic bond strength varies in each study. This study aims to optimize the air-particle abrasion protocol. Material and methods: 820 cylindrical nickel-chrome specimens divided equally into 82 groups (n:10). The specimens' s surfaces were air-particle abraded with 50, 110, 250 μm Al2O3 at 25, 50,75 psi for 10, 20, 30 s at a distance of 10, 20, 30 mm. To determine the surface roughness, profilometer and atomic force microscope were used. Veneering ceramic was fired onto the specimens and shear bond tests were performed with a universal testing machine. Statistical analyzed were performed using analysis of variance (Kolmogorov–Smirnov). Results: The difference of surface roughness between all groups were statistically significant (P |
