A novel zirconia fibre-reinforced resin composite for dental use

The purpose of this study was to evaluate and compare some biomechanical properties such as fracture toughness, Vickers hardness and compressive strength of an experimental fibre-reinforced composite (FRC) filled with various percentages (0 wt%, 1 wt%, 3 wt%, and 5 wt%) of zirconia (ZrO2) fibres.

A resin matrix (78.4 wt% bis-GMA, 19.6 wt% MMA, 1-wt% CEMA and 1 wt% CQ) with different percentages of silanized zirconia fibres (0%, 1%, 3%, and 5% by weight of the resin matrix) was prepared. Silanization was carried out using an experimental silane blend (0.5 vol% bis-1,2-(triethoxysilyl)ethane+1.0 vol% 3-acryloxypropyltrimethoxysilane in ethanol, at pH 4.0). Each group of specimens was stored in two conditions - either at room temperature for one day or water storage at 37 °C for 7 days. They were randomly divided into study groups according to the test method. For fracture toughness, a notchless triangular prism (NTP) test (n=6) was undertaken. Hardness values (n=6) were measured by using a Vickers hardness testing machine and compressive strength (n=6) was tested. Scanning electron microscopy (SEM) images were taken at the fracture sites after fracture toughness test. The data were analysed by 1-way ANOVA (analysis of variance) and Bonferroni post-hoc tests (α=0.05).

The ANOVA test revealed that the experimental FRCs with 1 wt% and 3 wt% zirconia fibres showed statistically significant differences in Vickers hardness at dry condition and NTP fracture toughness after 7-day water storage, respectively. However, compressive strength of experimental groups exhibited no significant difference (p>0.05).

Silanized zirconia fibres reinforcement in resin is a novel FRC which have shown promising biomechanical properties.