Tensile bond strengths of composites to a gold-palladium alloy after thermal cycling.

Statement Of Problem: Many different materials and methods have been used to fabricate or repair veneer facings with composites, but only a few of these have been studied.

Purpose: This study compared the tensile bond strengths of composites to a gold-palladium alloy with the use of several surface treatment methods.

Material And Methods: Forty alloy specimens were cast in Eclipse (52% gold and 37.5% palladium) in the form of truncated cones. These specimens were divided equally into 4 groups. In group I, the bonding surfaces of the metal cones were treated with Silicoater MD. Truncated cones of Dentacolor composite were bonded to the metal surfaces and light-polymerized. In group II, the bonding surfaces of the metal cones were air-particle abraded with 50 microm aluminum oxide and coated with C&B Metabond. Truncated cones of Epic-TMPT composite were bonded to the metal surfaces and light-polymerized. In group III, the bonding surfaces of the metal cones were air-particle abraded with CoJet-Sand. Truncated cones of Pertac-Hybrid composite were bonded to the metal surfaces and light-polymerized. In group IV, the bonding surfaces of the metal cones were air-particle abraded with CoJet-Sand. Truncated cones of Visio-Gem were bonded to the metal surfaces and light-polymerized. After 24 hours of water immersion at 37 degrees C and 1000 thermal cycles in water at 5 degrees C and 55 degrees C, tensile forces were applied to all specimens with a universal testing machine. Analysis of variance was applied to the data (P<.05), and differences among means were determined with a Tukey-Kramer interval of 5.4 MPa.

Results: Tensile bond strengths in MPa were as follows: Dentacolor, 14 +/- 5; Epic-TMPT, 12 +/- 4; Pertac-Hybrid, 13 +/- 5; and Visio-Gem, 18 +/- 4. The tensile bond strength of Visio-Gem was significantly higher than that of Epic-TMPT, but no differences were found among Dentacolor, Pertac-Hybrid, and Epic-TMPT (P<.05).

Conclusion: Within the limitations of this study, all 4 bonding systems tested produced high bond strengths between composites and a gold-palladium alloy after thermal cycling.