[Adhesion of polysulfide rubber impression material to dental metals (author's transl)].

In order to investigate the adhesiveness of polysulfide rubber impression material to dental metals, we performed the tension test on the sample specimens which had been prepared by injecting the impression material into the gap between opposite metal surfaces finished brightly, thereafter observed the fractured surfaces. Pure metals decreased their adhesive strength to the impression material in order of Au, Pd greater than Ag greater than Cu. Some noble metal alloys containing gold and palladium in a large amount showed the good adhesiveness. In clinical using of 14 carat gold and gold-palladium-silver alloys for core metal, it should be noticed that polysulfide rubber adheres tightly to these alloys. Adhesive strength of copper was not so great comparing with noble metals, therefore the surface of copper tray should be roughned by emery paper above #500, aiming the mechanical bonding forth to increase. The surface of many metals which had left in regulated atmosphere for many hours showed the tendency to decrease their adhesiveness to the impression material. This tendency was not recognized on the metals which had appeared the failure of adhesion bond on the bright finished surfaces.