The use of a photoprotective agent to increase the color stability of a tinted extraoral prosthetic silicone.

PURPOSE This study investigated the use of ultraviolet-absorbing or photoprotective agents as a method of decreasing the color changes caused by ultraviolet radiation on an intrinsically tinted facial prosthetic material. MATERIALS AND METHODS Silastic MDX 4-4210 (Dow Corning Corp, Midland, MI) was the facial prosthetic material studied. It was intrinsically tinted with talc and nylon flock to approximate the color of skin. Three brands of commercially available sunscreens with sun protective factor (SPF) of 15 were placed on the surface of the cured silicone samples. The samples were rotated in an ultraviolet radiation chamber for 300 hours. A control group was placed in the dark for 300 hours. The second phase of the experiment had para-aminobenzoic acid (PABA) added to the tinted silicone. All samples were measured with a spectrophotometer at the beginning and at the end of 300 hours, and a delta E was obtained. RESULTS None of the sunscreens provided any ultraviolet radiation protection to the silicone. The addition of PABA caused a significant color degradation of the silicone. CONCLUSIONS No photoprotective agent tested provided any significant level of ultraviolet radiation protection for silastic MDX 4-4210.