Effect of addition of pigments and opacifier on the hardness, absorption, solubility and surface degradation of facial silicone after artificial ageing

The physical properties of silicone prostheses can be influenced by materials used for aesthetic detailing. The purpose of this study was to investigate the effect of two pigments and one opacifier on hardness, absorption, and solubility of a facial silicone subjected to accelerated ageing. Silicone specimens were fabricated with or without pigments and opacifier. 120 specimens were produced, with half being used for hardness testing and the other half for absorption and solubility tests. The specimens were divided into the following 6 groups (n = 20) according to whether they were made with nanofiller with pigments and opacifier: colourless (I), colourless with opacifier (IO), ceramic (C), opacifier with ceramic (OC), oil (O), and oil with opacifier (OO). The specimens were subjected to accelerated ageing for 1008 h. Hardness, absorption, and solubility were measured at baseline (B) and after 253 h (A1), 504 h (A2), and 1008 h (A3) of accelerated ageing. The data were analysed by 2-way repeated-measures analyses of variance (ANOVA) and Tukey's HSD test (α = 0.05). The lowest hardness values were obtained for the O and OO groups (ps < 0.05 vs. other groups). Absorption and solubility did not differ between the groups, regardless of ageing period. Hardness, absorption, and solubility values did differ between the ageing time points. The use of nanofillers and opacifier did not affect the absorption and solubility properties of the silicone. However, the oil paint may have affected the polymerization of the silicone leading to initially lower hardness values.