COLOR CHANGES IN DRY-PIGMENTED MAXILLOFACIAL ELASTOMER RESULTING FROMULTRAVIOLET-LIGHT EXPOSURE

Five dry pigments and one maxillofacial elastomer were evaluated for c olor changes (Delta E) resulting from prolonged exposure to two types of ultraviolet light. The elastomer, pigments, and pigmented elastomer s were subjected to each ultraviolet light source for 400, 600, and 18 00 hours, and Delta E color shifts were determined. The unpigmented el astomer underwent minimally perceptible color change after 600 hours o f exposure to both types of ultraviolet light. Two pigments underwent substantial color change after 400 hours, whereas the remaining three pigments remained color stable after 1800 hours. It was concluded that for the materials tested, early color changes in a prosthesis may be the result of degradation of certain ultraviolet light-susceptible pig ments, whereas longer term color shifts may be caused by color changes within the elastomer.