Abstract
The bonding durability of four kinds of metal-resin veneers to a Ag-Pd-Cu-Au alloy was evaluated by the shear bond strength and impact resistance. The surface of cast alloy was treated with only Al_2O_3 sandblasted on polished surface or applied to the beads before casting. Then resin veneers φ 6×2 mm were fabricated according to the manufacturer's instructions. Specimens were stored in water at 37℃ for 24 hrs as a control and 30 days or thermocycled for 5,000 times between in water baths of 4℃ and 60 ℃. The results indicated that when treatment was applied to beads, bonding strength and their durability was effectively improved. After immersion for 30 days, the shear bond strength of the two kinds of veneers was higher than that of the control. The fractography after impact test implied that cracks initiated in the opaque resin and propagated into or along the interface between the resin and the alloy. From results of the flexural test and of previously described, it was suggested that the opaque resin was not cured sufficiently and has poor mechanical properties compared to those of the body resin. The degree of conversion of the opaque resin and the wettability between the resin and the filler should be improved to increase the bonding durability of metal-resin veneers.
