Boron Nitride Nanoplatelets as Reinforcement Material for Dental Ceramics

Abstract

Objective: The main goal of this research was to demonstrate the potential value of boron nitride nanoplatelets (BNNPs), which have excellent mechanical properties and biocompatibility, as a suitable reinforcement for dental materials.

Methods: The BNNPs were prepared by exfoliating h-BN via high-energy ball-milling and dispersion on a zirconia matrix. Then the composite powder was consolidated using spark plasma sintering. Fracture toughness, flexural strength and wear resistance were the mechanical properties explored. Agar diffusion-based biocompatibility testing was carried out. Low temperature degradation tests were also performed in a steam environment in an autoclave.

Results: The BNNPs dispersed zirconia exhibited improved strength (up to 27.3%), and fracture toughness was also increased (up to 37.5%) with the addition of 1-1.5 vol.% BNNPs. Tribological properties were also enhanced by the addition of BNNPs. The cytotoxicity tests confirmed that the BNNPs do not have obvious toxicity. The accelerated low-temperature degradation experiment revealed the barrier properties of the BNNPs, whose addition almost fully inhibited the degradation of the zirconia matrix in a humid environment.

Significance: The main contribution of this study is the introduction of an advanced material, BNNP, which can be used as a biocompatible reinforcement for dental materials, resulting in enhanced mechanical properties of the system due to its unique structure and extraordinary properties.