Porcelain repair - Influence of different systems and surface treatments on resin bond strength

PURPOSE The purpose of this study was to evaluate the bond strength of composite resin on the fracture surface of metal-ceramic depending on the repair systems and surface roughening methods. MATERIALS AND METHODS A total of 30 disk specimens were fabricated, 15 of each were made from feldspathic porcelain and nickel-chromium base metal alloy. Each substrate was divided into three groups according to the repair method: a) application of repair system I (Intraoral Repair Kit) with diamond bur roughening (Group DP and DM), b) application of repair system I with airborne-particle abrasion (Group SP and SM), and c) application of repair system II (CoJet Intraoral Repair System, Group CP and CM). All specimens were thermocycled, and the shear bond strength was measured. The data were analyzed using the Kruskal-Wallis analysis and the Mann-Whitney test with a significance level of 0.05. RESULTS For the porcelain specimens, group SP showed the highest shear bond strength (25.85 ± 3.51 MPa) and group DP and CP were not significantly different. In metal specimens, group CM showed superior values of bond strength (13.81 ± 3.45 MPa) compared to groups DM or SM. CONCLUSION Airborne-particle abrasion and application of repair system I can be recommended in the case of a fracture localized to the porcelain. If the fracture extends to metal surface, the repair system II is worthy of consideration.