Light-weight RTV silicone for maxillofacial prostheses.

Weight is a problem in retention of large skin-textured maxillofacial prostheses. The purpose of this investigation was to test the feasibility of mixing foam RTV silicone rubber with conventional RTV silicone rubber to obtain a light-weight material. Various mixtures of foam and conventional silicone rubber were formulated and tested for strength, accuracy of molding, color application, color stability, and texture. A special flask to support the mold was necessary in order to overcome expansion problems associated with gas formation of the foam silicone rubber. The mold required venting to release the gas and to reduce the expansion of the prosthesis in order to maintain accuracy. Molding, accuracy, texture, and color problems were overcome. Reduction of weight proportionate to reduction of tear strength of the material formulated, however, did not allow routine use of mixtures of foam and conventional silicone. When the weight of a prosthesis is critical and excessive and thickness is sufficient to give adequate strength, the foam and conventional silicone mixture can be used.