IMPROVEMENT OF BONDING DURABILITY OF DENTAL NOBLE METAL ALLOYS

通过体外剪切试验，评价了合金成分、底漆和热循环对银钯铜金合金粘结强度的影响。两种不同直径的圆盘试样由三种市售（S12、S20和Castwell M.C.12）和四种实验性银-钯-铜-金合金（K1、K2、K3和K4）铸造而成，后者的铜含量均超过20%。样品要么不底漆，要么用金属调理剂（V-Primer）底漆，然后用粘接树脂（Super-Bond Opaque）粘合，然后进行剪切测试。结果表明，无论是否添加调理剂，低铜S12和S20合金的热循环后结合强度都低于Castwell合金。热循环后K1、K2、K3和K4合金的结合强度与Castwell合金相同。对于除S12外的所有组（无热循环），使用金属表面调理剂可以提高结合强度。热应力的施加大大降低了未启动基团的键强度，而两个启动基团（K1和K2）的键强度不受热循环的影响。最好使用20%铜银钯铜金合金，结合V-Primer调节剂和Super-Bond粘合剂，实现持久的粘合。

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.