Mechanical behavior, numerical simulation, and cytotoxicity assessment of silicon nitride for dental application

Abstract

This study aimed to evaluate the potential of silicon nitride as a material for dental implants, focusing on its key properties, including high mechanical strength, chemical compatibility, excellent imaging characteristics, and antibacterial activity. Therefore, samples of silicon nitride ceramics with SiO2 and CaO as additives were pressureless sintered at 1800 ◦C for 1 h, and then characterized in terms of microstructure, mechanical properties, and biological behavior. Additionally, the mechanical behavior of a Si3N4 implant under masticatory loads was simulated using the Mohr-Coulomb criterion to assess risk of failure. The results showed that the prepared silicon nitride ceramic was non-cytotoxic and exhibited density, Vickers hardness, fracture toughness, compressive strength and Young’s modulus of 3.10 ± 0.01 g/cm3, 12.17 ± 0.35 GPa, 7.54 ± 0.78 MPa m1/2, 1497.42 ± 74.06 MPa, of 211.23 ± 63.81 GPa, respectively. It demonstrates that the material is a promising ceramic for dental implants, especially when compared to conventional biomaterials typically used in implant applications. Supported by the experimental results, numerical simulations using the finite element method suggested that the Si3N4-based ceramic developed in this work was able of withstanding masticatory loads of up to 400 N (under normal, compressive loads) and 350 N (under occlusal loads), without risk of failure, within the simulation parameters adopted in this study.