Preparation and characterization of mechanical properties of boron nitride nanosheets (BNNSs)-reinforced resin-matrix ceramics for dentistry.

OBJECTIVE

To evaluate mechanical properties and wear resistance of resin-matrix ceramics reinforced with mechanically produced boron nitride nanosheets (BNNSs) MATERIALS AND METHODS: BNNSs were dispersed using a mechanical ball-milling technique and incorporated into resin-matrix ceramics at 0.3 %, 0.5 %, 0.7 %, and 0.9 % (wt%). Three-point flexural strength, microhardness, and fracture toughness of the materials were assessed to evaluate the mechanical properties of the resin-matrix ceramics, evaluating the optical properties of resin-matrix ceramics by measuring transmittance, while the wear coefficient and wear rate were measured to determine their wear characteristics. Scanning electron microscopy was employed to analyze the fracture toughness tested sections and wear test surfaces.

RESULTS

Mechanical properties, transmittance, and wear were differently affected by different concentrations of BNNSs. Flexural strength and microhardness were higher at 0.5 wt% BNNSs group, which increased by 18.04 % and 19.8 % respectively when compared with the control group. While fracture toughness increased as BNNSs concentration also increased. Under the condition of 0.9 wt% BNNSs group, the value is larger, which increased by 73.3 % compared to the control group. The transmittance decreased with the addition of BNNSs, with the 0.9 wt% BNNSs group exhibiting a 22.49 % reduction compared to the control group. At 0.5 % BNNSs group, the wear rate was comparatively low, which was 31 % lower than that of the control group. At 0.5 wt% BNNSs group, the wear coefficient is the smallest, at 0.42. SEM analysis suggested that BNNSs reduced the peeling of the filler.

SIGNIFICANCE

This study provides an opportunity for the application of nanotechnology in the mechanical properties of resin-matrix ceramics and has the potential to contribute to a new generation of restorative materials in clinical treatment.