Impact of a mixture of nanofiller and intrinsic pigment on tear strength and hardness of two types of maxillofacial silicone elastomers

Abstract

The ideal maxillofacial prosthesis should have fine and thin boundaries that bind with the surrounding facial structures and possess high tear strength. This study aims to determine the best percentages of nanofiller (TiO2) and intrinsic pigment (silicone functional intrinsic) that could be mixed in as additives to improve the tear strength of Cosmesil M511 and VST50F silicone elastomers with the least effect on their hardness. In this in vitro experimental study, a total of 80 samples, 40 for each elastomer, were fabricated. Each elastomer sample was split into two equal groups to test for tear strength and Shore A hardness. Each group consisted of 20 samples, including 10 control samples without additives and 10 experimental samples with additives (mixtures of 0.2 wt% nano-TiO2+ 0.25 wt% intrinsic pigment and 0.25 wt% nano-TiO2+ 0.25 wt% intrinsic pigment for the Cosmesil M511 and VST50F silicone elastomers, respectively). Two-way ANOVA and Tukey test were used for comparison; P < 0.05 was considered statistically significant. Significant differences in tear strength were found among all tested groups (P < 0.05). The tear strength of the experimental subgroups significantly increased compared with the control subgroups (P < 0.05). Significant differences in Shore A hardness were also observed among all tested groups (P < 0.05) except between the experimental subgroups of both materials, where a nonsignificant difference was obtained (P > 0.05). Incorporation of select percentages of TiO2 nanofiller and intrinsic pigment into Cosmesil M511 and VST50F silicone elastomers yields improvements in tear strength with a slight increase in hardness.