Influence of pigments and pigmenting methods on color stability of different silicone maxillofacial elastomers after 1-year dark storage.

Purpose: The purpose of this study was to measure spectrophotometrically the color changes of pigmented maxillofacial silicone elastomers with different pigments and pigmenting methods after storing 1 year in the dark environment.

Methods: Three maxillofacial silicones, Cosmesil M511 (CosM511), Cosmesil M522 (CosM522), and Multisil-Epithetic (Mult-Epit), were selected for this study. A total of 240 specimens were fabricated; 80 of each of the 3 elastomers (n = 5) (18 mm in diameter and 2 mm in thickness) were prepared in 6 colorant categories (5 colorant and 1 with no colorant). Specimens were stored in a black box representing a condition of total darkness and placed in a dark environment at ambient room temperature (22°C ± 10°C) and humidity (50% ± 10%) for 1 year. A color spectrophotometer was used to measure the ΔE* values of the test specimens to determine the color changes.

Results: The lowest color changes were observed in CosM511 in white color (ΔE* = 1.31) and in Mult-Epit in white color (ΔE* = 1.82) in extrinsic coloration group. The highest color changes were observed in yellow color in CosM511 (ΔE*= 21.61) and CosM522 (ΔE*= 23.78) in silicone pigmented intrinsic coloration method. In coloration methods, intrinsic silicone pigmented groups in all colors except brown in Mult-Epit had the highest ΔE* values.

Conclusions: Significant color changes were observed in both pigmented and unpigmented specimens, which were stored in dark environment and not exposed to sunlight.