Study on the Bonding between Ni-Cr Alloys and Porcelain and the Fitness of Metal Coping to Metal Die

Abstract

Study on the Bonding between Ni-Cr Alloys and Porcelain and the Fitness of Metal Coping to Metal Die.
The base metal alloys for porcelain firing have recently been used because of the increase in the cost of precious metal alloys. And also, these alloys were prefered in the mechanical strength.
The base metal alloys remain unknown problems in bonding between the porcelain and alloys. Furthermore, in the case of base metal alloys, the fitness of metal coping to prepared teeth are less than in precious metal alloys.
The purpose of this study was to investigate the element behavior at the porcelain metal interface after firing, and to measure bonding strength and the deformation of metal coping obtained by firing.
The results were as follows:
1. The bonding between Ni-Cr alloy and porcelain.
1) It was not concluded that roughness contributes mechanical interlocking or increse of reaction area from this experiment.
2) The segregation of Sn, Al was marked at the porcelain/metal interface.
3) Shear strength at the interface was not significant between Ni-Cr alloy and precious alloy.
2. The metal coping was considerably deformed by repeated firing.
3. The space for cementation of metal coping to metal die was 300-350μm at marginal shoulder, 35-60μm at labial side, 300-350μm at edge, 20-45μm at lingual side.