THE EFFECT OF TIN-ELECTROPLATING ON THE BOND OF 4 DENTAL ALLOYS TO RESIN CEMENT - AN IN-VITRO STUDY

Statement of the problem. Nickel-chromium alloys are indicated for the construction of resin-bonded fixed partial dentures; however, the pot ential toxicity of nickel has been a source of concern. Composite ceme nts do not develop an adequate bond to air abraded noble alloys, which cannot be electrolytically etched. Tin-electroplating of noble alloys appears to be an alternative treatment for resin bonding. Purpose. Th is in vitro study investigated the effect of tin-electroplating on the bond of a composite cement to base and noble alloys. Material and met hods. Tensile tests were made with disks of four alloys that were ceme nted to each other with an adhesive composite cement after (1) air abr asion with 50 mu m aluminum oxide and (2) air abrasion plus tin-electr oplating. Results. Tin-electroplating increased the bond strength of m etal-ceramic gold alloy (Au,Pd,Pt) to a level comparable to the nickel -chromium alloy, but had a harmful effect on type IV gold alloy. Concl usions. Despite the recommendation for tin-electroplating of type IV g old alloys, this procedure did not improve bond strength to composite in this study.