BONDING STRENGTHS OF PORCELAIN REPAIR SYSTEMS WITH VARIOUS SURFACE TREATMENTS

Statement of problem. Metal porcelain combined surfaces are often invo lved in the repairing of fractured porcelain fused to metal restoratio n. Purpose. This study investigated the effect of surface treatments o n the bonding strength of porcelain fused to metal prosthesis repair. Material and methods. Specimens (8 x 4 mm) were fabricated with Biobon d II casting alloy and randomly divided into three surface groups: met al, porcelain, and metal-porcelain combined surface. Biobond porcelain system and commercially available porcelain repair systems were reste d. The metal surface group was further divided into two subgroups: con trol and sandblasting treatment (Al2O3, 50 mu m, 20 seconds). In the p orcelain surface group, there were three subgroups: (1) control, (2) s andblasting, and (3) 9.5% hydrofluoric acid etching for 4 minutes. The metal-porcelain surface combined group was divided into three subgrou ps: (1) control, (2) sandblasting, and (3) sandblasting and etching. T he manufacturer's instructions for repair systems were followed for sp ecimen preparation. hear bond strengths of 10 specimens For each subgr oup were determined with a universal testing machine after storing in distilled water at 37 degrees C for 7 days. The data were analyzed wit h analysis of variance and Scheffe F-test at the 95% significance leve l. Results. The Liner-M repair system showed significantly greater str ength than the other tested systems on the metal surface with or witho ut sandblasting treatment (p < 0.05). On the porcelain surface, the st rengths of sandblasting and etching subgroups ranged from 7.2 to 16.8 MPa, and 6.8 to 16.8 MPa, respectively. There were no significant diff erences in bond strengths between sandblasting and combined treatment of the metal-porcelain combined surface group (P > 0.05). Conclusion. The results of this study suggest that metal substrates treated with s andblasting and porcelain treated with either hydrofluoric acid or san dblasting can increase repair strength.