Bonding of an indirect composite material to a magnetic stainless steel alloy

Purpose: The purpose of the present study was to investigate the bond strength of an indirect composite material to a magnetic stainless steel alloy. Materials and Methods: The surfaces of machined magnetic stainless steel alloy specimens were abraded with 600-grit silicon carbide paper and then grouped according to the type of surface treatment given: 1) without preparation, 2) tribochemical silica coating, 3) air abrasion with 50 μm alumina, 4) tribochemical silica coating and application of opaque resin, 5) air abrasion and application of a metal conditioner for base metal alloys, and 6) air abrasion, application of a metal conditioner and opaque resin. An indirect composite material (Estenia C&B) was then applied to the treated surfaces of the alloy and polymerized. The specimens in groups 2-6 were thermocycled up to 10,000 cycles. The specimens in groups 5 and 6 were thermocycled up to 20,000 cycles. The shear bond strengths were determined using a universal testing machine. Results: All of the cylindrical columns of the indirect composite material in group 1 debonded before their shear bond strengths could be determined. Group 6 exhibited the greatest bond strength, followed by group 5, compared to the other groups before thermocycling (p<0.05). The bond strengths of groups 3-6 did not decrease after thermocycling (p>0.05), whereas those of group 2 significantly decreased (p<0.05). Conclusion: Significant improvement in the bond durability of an indirect composite material to a magnetic stainless steel alloy was achieved by alumina air abrasion and the application of a metal conditioner for base metal alloys and opaque resin, followed by pre-polymerization. (Asian Pac J Dent 2012; 12: 27-31.)