UBC Theses and Dissertations
A comparison of the mechanical properties of pigmented silicone elastomers used in maxillofacial prostheses El-Mowafy, Nora
Purpose: To evaluate and compare the mechanical properties of various commercially available pigmented polydimethylsiloxane elastomers (silicone elastomers) utilized in the fabrication of maxillofacial prostheses. Materials & Methods: Three commonly used silicone elastomers were evaluated: A-2000 (Factor II), A-2186 (Factor II), A-103 (Factor II). The silicones was combined with opacifier: Titanium White (Factor II), and pigment: Intrinsic Pigment in Naturelle (Factor II). Specimens were fabricated through the use of aluminum and stone moulds to form trouser- and dumbbell- shaped specimens. From each material 20 specimens were prepared, 10 dumbbell-shaped and 10 trouser-shaped (n=10) for a total of 60 specimens. Mechanical properties evaluated included: Shore-A hardness, tear strength, tensile strength, and percent elongation. These properties were tested according to ASTM protocols. Data was statistically-analyzed with one-way ANOVA of each property at the 95% level of confidence as well as Tukey’s post-hoc tests for specific identification of significant differences between materials. Results: ANOVA indicated statistically-significant differences among the three materials for each of the four outcomes tested. Further statistical analysis with Tukey’s post-hoc tests showed significantly lower tensile strength and tear strength and higher % elongation for A-103 when compared to both A-2000 and A-2186. No statistically significant differences were found between A-2000 and A-2186 with respect to tensile strength, percent elongation or tear strength. All three groups were found to be significantly different from each other in terms of Shore-A hardness. A-103 exhibited the lowest hardness values, whereas A-2186 was found to have the highest hardness. iii Conclusions: Material A-103 exhibited the lowest tensile and tear strengths as well as hardness, however, it displayed the greatest percent elongation. Material A-2000 and A-2186 displayed similar characteristics with regard to tensile and tear strengths, but differed in terms of Shore-A hardness with A-2186 exhibiting the greatest hardness.
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