The physical and chemical stability of the intrinsic pigments for facial prosthesis was investigated in order to improve the color stability when using it.
In the present study, TH/Red I and TH/Blue of SILSKIN® as intrinsic pigments and DOW CORNING® MDX-4-4210 as base elastomer were selected. The effects of the curing temperature and time (75°C: 80-260 minutes, 125°C: 40-130 minutes) in processing and the ultraviolet light irradiation (0-1, 008 hours) after processing on these pigments were evaluated by measuring the weight of the pigments in the materials.
The findings were as follows:
1. With regard to the curing temperature, the weight of both pigments did not change at 75°C but decreased at 125°C. The greatest degree of the decrease was observed at over 100 minutes of curing time. The degree of the decrease of TH/Blue was greater than that of TH/Red I.
2. With regard to ultraviolet light irradiation after processing, the weight of the pigments decreased with the increase of the irradiation period. The degree of the decrease of TH/Red I was greater than that of TH/Blue.
3. The effect of ultraviolet light irradiation after processing varied with TH/Blue according to the curing temperature but this was not observed with TH/Red I.