Feasibility Of Repairing Collapsed Crown And Fixed Bridge By Porcelain Jacket Crown

Object:To test the bond strength of single porcelain jacket crown, thus determining the feasibility of clinical application of repairing collapsed crown and fixed bridge by porcelain jacket crown, and meanwhile to discuss the influence between blastsanding and silane coupling agent treatment on the metal bonding strength in the repair of porcelain fracture. Methods:The porcelain jacket crown was cast in the same shape from disk-shaped waxpatterns. Twenty specimens were chosen without blowholes and casting defects and they were all routinely burnished and cleaned in an ultrasonic bath and dried using an oil-free air stream stand-by. Then randomly we divided the specimens into four groups:specimens were treated with nothing (control), sandblast, silane coupling agent and sandblast+silane coupling agent, respectively. Each of the specimen was bonded with Poly-F Plus. AG-10TA universal testing machine was used to test the tensile strength.Results:The tensile bond strength of control, sandblast, silane coupling agent and sandblast+silane coupling agent groups respectively were (0.68±0.04) kN,(1.00±0.02) kN,(1.31±0.08) kN, and (1.09±0.04)kN. There were a big significant differences between the groups (p<0.01). In the control group, the metal surface was smooth, showing some irregular small superficial veins under the electron scanning microscope. In the sandblast group, the metal surface showed irregular scaly protrusions conducive penetrate adhesives. In the silane coupling group, the metal surface manifested a honeycomb structure in favor of chimeric adhesives.The sandblast+silence coupling agent group showed some metal projections ranging in size, on the rough metal surface, which was conducive to bond.Conclusion:Porcelain jacket crown applied to repair collapsed crown and fixed bridge is feasible. Sandblasting and silane coupling agent can improve bond strength of porcelain jacket crown. The bond strength of metal specimens treated with silane coupling agent is the best followed by the sandblasting+silane coupling agent.And then followed sandblasting group.