Evaluation of some mechanical properties of a new silicone elastomer for maxillofacial prostheses after addition of intrinsic pigments

OBJECTIVE: The approximate life span of a silicone maxillofacial prosthesis is as short as 1.5–2 years of clinical service, then a new prosthesis should be fabricated. The most common reason for re-making the prosthesis is silicone mechanical properties degradation. The aim of this study was to assess some mechanical properties of VST-30 silicone for maxillofacial prostheses after addition of intrinsic pigments. METHODS: Two types of intrinsic pigments (rayon flocking and burnt sienna); each of them was incorporated into silicone. One hundred and twenty samples were prepared and split into 4 groups according to the conducted tests (tear strength, hardness, surface roughness, and tensile strength and elongation percentage) with 30 samples for each test. Each group was equally split into three subgroups. Group (A) was without pigment (control group), group (B) was with rayon flocking and group (C) was with burnt sienna. RESULTS: Samples with rayon flocking showed a highly significant decrease in hardness and there was a significant increase in tear strength, while there were non-significant differences in surface roughness, tensile strength and elongation percentage. Samples with burnt sienna showed a highly significant increase in tear strength and a highly significant decrease in hardness, but surface roughness, tensile strength and elongation percentage showed non-significant differences. However, there were non-significant differences between experimental groups in all tests. CONCLUSIONS: The addition of each of rayon flocking and burnt sienna changed the mechanical properties of the VST-30 silicone, while no superior pigment-silicone combination was revealed in all the conducted tests.