Properties of silicone maxillofacial elastomer processed in stone and metal.

1. The effect of mold conditions on the UTS, n, and TS at 200% and 300% elongations, and Shore A hardness was measured for Silastic 44210. 2. There was no difference in n, Shore A hardness, and TS at 200% and 300% elongation between Silastic 44210 samples whether produced in metal or coated stone molds. 3. The highest UTS for Silastic 44210 was demonstrated for samples processed in aluminum molds. The UTS was slightly reduced when coated stone molds were used, and it was considerably reduced with untreated stone molds. It is felt that the slight decrease in UTS with coated stone molds would not compromise the use of stone molds clinically, particularly when ease of processing is considered. 4. Petroleum jelly, silicone spray, and tinfoil substitute were all equally effective in improving the physical properties of the elastomer when processed in a stone mold. These results demonstrate the necessity of using a mold sealant when processing Silastic 44210 in a stone mold.