1996 Volume 40 Issue 1 Pages 90-96
Sintered metal restorations, made from powder metallurgy developed by Degussa Co., Ltd., and conventional cast restorations were prepared by using a metal modelfor MOD inlay. A comparative study was carried out, and the results were as follows:
1. As for surface roughness, no significant difference of Rz could be observed both on the polished surface and cavity floor. In the graphs of Rz on the cavity floor, the picture was rough for cast restorations and sink hole-like gas cavities were locally recognized on the surface of sintered metal restorations with a roughness of 3 μm on average. As the results of the corrosion test, roughness of the polished surface of both restorations rose and the increase was larger in cast restorations. Sintered restorations showed better corrosion resistance.
2. The fitness test showed no significant difference in the margin, butthe fitness of sintered metal restorations was inferior to cast restorations on the inner surface.
3. The surface hardness of sintered metal restorations was lower than the values indicated by the manufacturer.
Based on these results, it was considered that powder metallurgy was not suitable for the preparationof a thick abutment tooth with sharp angles such as MOD.
