Evaluation of the castability of four different alternative alloys by measuring the marginal sharpness.

The castability of two low-gold and two silver-palladium alloys was evaluated, using a Type III gold alloy as reference. Six castings from each alloy were subjected to a castability test, in which the marginal sharpness of simulated crowns--that is, the edge diameter--was used to assess the castability. The mean crown edge diameters of the silver-palladium alloys were three to four times the corresponding diameters of the gold-based alloys. The differences between these two groups were statistically significant. It is concluded that the castability of the low-gold alloys studied was comparable to that of the Type III alloy, whereas the silver-palladium alloys studied had a castability that may result in technical and clinical problems.