Effect of artificial sweat, pigmentation and adhesives for fixing facial prostheses on physical and optical properties of two facial silicones.

The aim of this study was to evaluate the effect of sweat and adhesives on color stability, roughness (Ra) and Shore A hardness of two silicones for facial prostheses with different pigmentation. Samples of Silastic MDX4-4210 and A-2186 silicone were made for the proposed tests, distributed into 12 groups according to their pigmentation and adhesive used and were immersed in artificial sweat for 3 months, disinfected every 3 days with neutral soap. Measurements of color stability, roughness and hardness were performed according to ISO 21920 and CIEDE2000 using a spectrophotometer and ISO 868, respectively. There was a statistically significant color change in the two silicones used, with the groups that had the least change being those without adhesive applied to their surface (controls). There was also a reduction in roughness in all groups, with MDX4-4210 being the roughest silicone. In terms of Shore A hardness, all the groups became harder after the experimental period, with A-2186 achieving the highest results. Color change, Shore A hardness and roughness showed significant changes in the MDX4-4210 and A-2186 silicones for the proposed tests. Even so, all the results found were clinically acceptable, making both silicones excellent options for use in maxillofacial rehabilitation.