Nowadays resin cements have been used for cementing fixed restorations increasingly. Many new resin cements have been introduced for clinical applications. This study compared shear bond strength of 5 resin cements ABC, Calibra, Panavia F, RelyX ARC and Super-Bond C&B to nickel-chromium-molybdenum-beryllium alloy and studied effect of 2 primers META FAST and ALLOY PRIMER on shear bond strength. Two sizes of alloy cylinders, diameter 7 and 9x2 millimeters thickness, 225 pairs sandblasted with 50 micron aluminum oxide, cleaned with ultrasonic cleaner, conditioned with 1 of 2 primers and bonded with 1 of 5 resin cements. After storing in distilled water for 24 hours, shear bond strength testing was performed with Lloyd instrument. Shear bond strength and mode of failure were recorded. Analysis of variances revealed significant effect on shear bond strength from type of resin cements and primer applications (P<0.05). Not regarding to primer applications, Tukey HSD's multiple comparison showed Panavia F and Super-Bond C&B yielded significantly higher mean shear bond strength than the other 3 resin cements. Panavia F showed insignificant difference in mean shear bond strength with Super-Bond C&B. Not regarding to type of resin cements, using resin cement with ALLOY PRIMER or META FAST yielded significantly higher mean shear bond strength than using resin cement with no primer. Using resin cement with ALLOY PRIMER yielded insignificant difference in mean shear bond strength with using resin cement with META FAST. Chi-square test revealed significant relation between mode of failure and primer applications in all resin cements except Calibra. Mean shear bond strength of mixture adhesive and cohesive failure founded higher than mean shear bond strength of adhesive failure in all resin cements but significant difference with RelyX ARC only.
