Evaluating the Mechanical Properties of Maxillofacial Silicone Enhanced by Hexagonal Boron Nitride Particles

Maxillofacial silicone is the most popular and commonly used material for the construction of maxillofacial prostheses. However, the material failed to satisfy the expected features of a maxillofacial prosthesis due to major limitations, particularly in mechanical properties. The goal of this study is to evaluate the mechanical properties of the VST-50F silicone elastomer with the addition of hexagonal boron nitride (H-BN). A total of 120 specimens were prepared and divided into three groups control and two experimental (0.5 wt% and 0.7 wt% H-BN). Each group was divided into four identical subgroups. For each subgroup, 10 specimens were utilized for each test (tear strength, tensile strength, Shore A hardness, and surface roughness). The H-BN powder and specimens from each group were studied using field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). The data were analyzed using one-way ANOVA and post-hoc Tukey’s tests, and a P-value < 0.05 indicated statistical significance. The FE-SEM test showed evenly dispersed H-BN within the VST-50F silicon matrix. The FTIR test revealed no chemical interaction between the silicone and H-BN. Both experimental groups showed significantly increased tear strength and decreased Shore a hardness and surface roughness (P < 0.05). The 0.5 wt% group exhibited no significant decrease in tensile strength, but the 0.7 wt% group showed a significant decrease compared to the control group (P < 0.05). As the quantity of H-BN increased, tear strength improved, whereas tensile strength, Shore a hardness, and surface roughness reduced.