Shear bond strength of resin composite to magnetic Fe-Pt alloy

Statement of problem

It is important to obtain strong adhesion between resin composite material and magnetic Fe-Pt alloy for fabrication of an indirect veneered crown. However, little is known about the bond strength between these materials.

Purpose

This study evaluated the bond strength of resin composite to magnetic Fe-Pt alloy, using 4 adhesive metal primers.

Material and methods

Seventy disk-shaped patterns (7.5 mm in diameter, 2.0 mm thick) were cast from a custom-made Fe-Pt ingot using a high-frequency centrifugal casting machine. After the bonding surfaces were airborne-particle abraded with 50 μm Al₂O₃, specimens were divided into groups (n=7) and primed with either Metal Primer II (MP), Meta Fast Bonding Liner (BL), New Meta Color INFIS Opaque Primer (IN), or Epricord Opaque Primer (EP). Nonprimed specimens served as controls (n=7). A resin composite (New Meta Color INFIS) was then applied to all specimens and polymerized. After the specimens were immersed in 37°C water for 24 hours or thermal cycled at 4°C to 60°C with a 1-minute dwell time of up to 10,000 cycles, the shear bond strengths (MPa) were measured using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were statistically analyzed by a 2-way analysis of variance and the Scheffe test (α=.05).

Results

Although IN had the lowest strength, there were no significant differences in bond strengths of the other 3 primers (MP, BL, and EP) before thermal cycling. The bond strengths of MP and EP were slightly altered by thermal cycling (P>.05); however, BL and IN underwent a significant decrease (P<.05).

Conclusion

The results of this in vitro study indicate that MP and EP provide superior long-term shear strength when bonding the resin composite evaluated to Fe-Pt alloy.