Mechanical properties and bonding of maxillofacial silicone elastomers

Abstract

Objectives: Maxillofacial silicone elastomers are used to replace facial parts lost through disease or trauma. However, these materials do not possess ideal properties. The purpose of this study was to investigate the mechanical properties of recently and previously introduced maxillofacial silicone elastomers and their bond strength to acrylic resin substrate.

Materials and methods: Specimens of three maxillofacial silicone elastomers (TechSil S25, Cosmesil M511, and Cosmesil Z004) were prepared according to manufacturers' instructions. Tear and tensile strengths, elongation percentage, modulus of elasticity and hardness were evaluated for each material. Shear bond strengths of these silicone elastomers to primed acrylic resin surfaces were evaluated. Data was analyzed with 1-way ANOVA, Bonferroni, and Dunnett's T3 post hoc tests (P < 0.05).

Results: The tensile strength of S25 was higher than M511 and Z004 (P < 0.05). Also S25 had higher elongation percentage in comparison to the other materials (P < 0.05). Z004 and S25 were harder (P < 0.05) than M511. All materials had the same tear strength and modulus of elasticity (P > 0.05). Z004 had higher shear bond strength than S25 (P < 0.05). There was a positive linear correlation between shear bond strength, and tear strength (r = 0.974) and shore A hardness (r = 0.717).

Conclusions: All silicone elastomers tested showed desirable properties. TechSil S25 had more favorable combination of high tensile strength and elongation at break, comparable tear strength, and hardness within the favorable range. However, Cosmesil Z004 was more resistant to shear debonding than other silicone elastomers.

Significance: TechSil S25 silicone elastomer has promising properties that favor its use in fabricating maxillofacial prostheses.