Colour stability of Siloczest LSR 120 against Cosmesil M511 maxillofacial silicones under simulated environmental ageing conditions

TL;DR

This study compares how two types of silicone materials used in facial prostheses change color over time when exposed to simulated environmental conditions.

Contribution

The study provides a direct comparison of Siloczest LSR 120 and Cosmesil M511 under combined environmental stressors relevant to clinical use.

Findings

Both materials showed color changes, but Cosmesil M511 was more stable under neutral soap and combined sunlight and sweat.

Siloczest LSR 120 showed higher discoloration under neutral soap and combined conditions, but changes were within clinically acceptable limits for darker skin tones.

The combination of sweat and sunlight caused the greatest color degradation, especially in Siloczest LSR 120.

Abstract

Maxillofacial prostheses play a vital role in rehabilitating facial form and function, with long-term colour stability being a key determinant of patient satisfaction. These prostheses are routinely exposed to ultraviolet radiation, sweat, and cleaning agents, which may compromise their appearance over time.

To compare the colour stability of two maxillofacial silicone elastomers, Siloczest LSR 120 and Cosmesil M511 under simulated ageing conditions replicating clinical exposures.

A total of 80 samples (40 per material) were fabricated and divided into four subgroups based on ageing conditions: sunlight, artificial sweat, immersion in neutral soap, and a combination of sunlight and sweat. Colour measurements were recorded before and after 6 months of ageing, except for neutral soap (30 hours) using the Commission Internationale de l’Eclairage Lab* ( CIE L*a*b*) system via a spectrophotometer, and ΔE values were calculated. Data were analysed using SPSS v28. Normality was assessed with Kolmogorov-Smirnov and Shapiro-Wilk tests. Independent t-test and one-way analysis of variance with Bonferroni correction were used for inter- and intra-group comparisons.

Both materials exhibited colour changes under all conditions. No statistically significant difference was observed between Siloczest LSR 120 and Cosmesil M511 under isolated sunlight or sweat exposure. However, Siloczest LSR 120 showed significantly higher discolouration under neutral soap (ΔE-1.48) and combined sunlight and sweat conditions (ΔE-6.68) against Cosmesil M511 (ΔE-0.68 & 3.82 respectively), (p < 0.05). The combination of sweat and sunlight caused the greatest colour degradation, particularly in Siloczest LSR 120.

The results suggest that while Cosmesil M511 remains the more reliable option for long-term aesthetics, Silicozest LSR 120 demonstrates promising performance. Although its colour stability was comparatively poorer under neutral soap and combined exposure, the observed changes remained within clinically acceptable limits for darker skin tones (ΔE < 10.07), indicating that it can still be considered a viable material for clinical use in appropriate contexts.

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