Mechanical Evaluation of Boron Nanoparticle-Modified Silicone Elastomers for Maxillofacial Prostheses

This study evaluated the effects of boron nanoparticles (BNPs) on the mechanical properties of two silicone elastomers, A-2000 and A-2006. Tensile, tear, hardness, and elongation tests were conducted in accordance with ASTM and ISO standards. A total of 180 specimens were prepared, comprising control groups without BNPs and experimental groups containing 1 and 3 wt% BNPs. Tensile and tear strength tests were performed using a device with a 1 kN capacity at a crosshead speed of 100 mm/min; hardness was measured using Shore A tests, and Atomic Force Microscopy (AFM) was employed to assess surface roughness. Tensile testing revealed that the A-2000 control group exhibited the highest tensile strength, with significant reductions observed in both BNP-incorporated subgroups. In A-2006, tensile strength decreased significantly with 1 wt% BNPs but partially recovered at 3 wt%. Tear strength in A-2000 significantly decreased at 1 wt% but returned to control levels at 3 wt%, whereas no statistically significant differences were observed among the A-2006 subgroups. Hardness significantly increased with 3 wt% BNPs in A-2000 and with both 1 and 3 wt% BNPs in A-2006. Regarding elongation, A-2000 showed no significant change compared with the control, although the 1 and 3 wt% groups differed significantly from each other. In A-2006, both 1 and 3 wt% BNP groups showed significant reductions in elongation compared with the control. Overall, A-2000 exhibited superior tensile and tear strength, while A-2006 demonstrated greater elongation capacity. These findings indicate that BNP incorporation depends on both the elastomer type and concentration, with potential trade-offs between improved hardness and decreased flexibility. Both A-2000 and A-2006 remain viable options for maxillofacial prostheses, although optimization of BNP concentration is essential to balance strength, durability, and flexibility.