Airborne-particle abrasion; searching the right parameter.

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 AlO 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 < .05). The highest surface roughness value was measured in 110 μm, 75 psi, 20 mm and 30 s. The higher bond strength values were obtained in 110 μm, 75 psi groups and no statistically significant difference was observed within each group.

Conclusion: While all the air-particle abrasion parameters were effective on surface roughness, only the pressure and grain size make statistically significant difference on shear bond strength.