A study on the influence of nano-c-BN on the physical and mechanical characteristics of PMMA biocomposites used in dental prosthetics

Due to their high strength and exceptional thermal resistance, boron nitride (BN) nanostructures are a promising new type of reinforcement for medical applications. Among these, cubic BN (c-BN) nanoparticles are crystalline-shaped structural, combining extremely high hardness and thermal stability, which make them highly effective reinforcements in polymers. Their incorporation enhances material performance by increasing density, load-bearing capacity, and wear resistance. This study examines the influences of c-BN nanoparticle addition on the mechanical and wear characteristics of PMMA/c-BN biocomposites. c-BN nanoparticles (NPs) were added to the polymer matrix at different concentrations of 0, 0.5, 1, 2, 3, and 5 wt%. Measurements of bulk density, Vickers microhardness, ultimate compressive stress, yield stress, and wear resistance revealed that the properties of the fabricated composites were significantly improved by the increased concentration of c-BN nanoparticles in the matrix. Notably, the biocomposites containing a 5 wt% c-BN exhibited the highest bulk density, hardness values, and surface roughness of 1.221 ± 0.002 g/cm 3 , 79.5 ± 1.6 HV, and 125.52 µm, respectively; while the porosity decreased to 0.16% compared to other produced composites. In particular, the biocomposite produced at 3 wt% c-BN displayed the highest ultimate compressive stress, and yield stress: 215 ± 6.17 MPa, and 101.1 ± 2.2 MPa, respectively, with improvements of 99.07%, and 27.85% compared with the PMMA matrix. Additionally, the wear track profiles also showed improved wear resistance; this was confirmed by 3D surface roughness topography and experimental results for SEM images of worn surfaces. Due to their superior mechanical and wear resistance, PMMA biocomposites with c-BN NPs make excellent secondary reinforcement for a variety of medical applications, including dental prostheses.