IMPROVEMENT OF BONDING DURABILITY OF DENTAL NOBLE METAL ALLOYS

通过体外剪切试验，研究了合金成分、底漆和热循环对银-钯-铜-金合金粘结强度的影响。从三种商业可得的(S12、S20和Castwell M.C.12)和四种实验性的银-钯-铜-金合金(K1、K2、K3和K4)铸造了两个不同直径的圆盘样品，后者中的每一种都含有超过20%的铜。试件要么不涂底漆，要么用金属护理剂(V-Primer)底漆，用粘结树脂粘结(Super-Bond不透明)，然后进行剪切测试。结果表明，无论使用何种调理剂，低铜S12和S20合金的热循环后结合强度均低于Castwell合金。预涂K1、K2、K3和K4合金的热循环后结合强度与Castwell合金相同。除了一个组(S12，没有热循环)外，所有组的粘结强度都通过使用金属表面调节剂而提高。施加热应力显著降低了未启动基团的结合强度，而两个启动基团(K1和K2)的结合强度不受热循环的影响。希望使用20%的铜银钯铜金合金，通过V-Primer调理剂和Super-Bond粘合剂的组合实现持久粘接。

The influence of alloy composition, priming, and thermocycling on bond strength to silver-palladium-copper-gold alloy was evaluated in vitro by means of shear testing. Disk specimens with two different diameters were cast from three commercially available (S12, S20, and Castwell M.C.12) and four experimental silver-palladium-copper-gold alloys (K1, K2, K3, and K4), each of the latter containing copper more than 20%. Specimens were either unprimed or primed with a metal conditioner (V-Primer), bonded with an adhesive resin (Super-Bond Opaque), then shear testing was performed. The results showed that the low-copper S12 and S20 alloys showed lower post-thermocycling bond strength than the Castwell alloy regardless application of the conditioning agent. Post-thermocycling bond strengths of the primed K1, K2, K3 and K4 alloys were the same magnitude as that of the Castwell alloy. For all groups except for one (S12, without thermocycling), bond strength was elevated by use of the metal surface conditioner. Application of thermal stress drastically reduced bond strength of unprimed groups, whereas bond strength of the two primed groups (K1 and K2) was unaffected by thermocycling. It is desirable to use a 20%-copper silver-palladium-copper-gold alloy for achieving durable bonding with the combination of the V-Primer conditioner and the Super-Bond adhesive.