Tensile strength and microleakage of the bond between a nickel-chromium alloy and a visible light-cured resin composite: Effect of 4-META, silicoating, and bead retention

Three retention systems, 4-META adhesive, Silicoating, and a conventional retention beads system, were used for resin-metal bonding. For each group, 40 standard specimens were prepared (20 for microleakage testing and 20 for tensile strength testing). Wax patterns were prepared, invested, and cast with a nickel-chromium alloy. The metal surfaces of the specimens were sandblasted with 250-um aluminum oxide. Dentacolor Opaque was placed and set in a light curing unit for 90 seconds. Dentacolor resin composite w as placed and set in the same unit for 90 seconds. The bonded specimens were subjected to thermocycling process in baths of 5 degrees C and 55 degrees C with 30-second dwell time. The tensile strength test specimens were stored in water, and the microleakage test specimens were stored in 5% basic fuchsin dye for 2 days. The means of the tensile strength test groups were not significantly different. However, the differences in microleakage among groups were found to be statistically significant. As a result, 4-META and Silicoating systems were found to be better than the conventional retention beads system, which allowed the greatest microleakage.