Objective To investigate the influence of three primers on the shear bond strength between cast titanium (Ti) and composite resin.Methods The disks (n=40) were cast by commercially pure (CP) Ti，which diameter were 8 mm and thick were 3 mm. The titanium surfaces were polished with silicon carbide sand papers under running water and then treated by sandblasting and acid (4%HF) etching. They were divided into four groups: control group (group A), treated with KH-570 (group B), treated with Alloy Primer (group C), treated with Metal photo primer (group D). After treatment, the specimens were evaluated for their shear bond strengths by universal testing machine. The values were statistically analyzed. The frac-tured surfaces were observed by scanning electron microscope (SEM).Results The shear bond strengths of group A, B, C, D were (9.773±0.67), (11.463±0.82) , (14.224±0.75), (13.157±0.73) MPa. There were significant differences in bond strength between A and B, C, D (P0.05).Conclusion KH-570, Alloy Primer, Metal photo primer significantly improve the bond strength of ceramage composite resin to cast titanium. KH-570 group bonding strength is lower than the the Alloy Primer group and Metal photo primer group.
