Surface modifications of short quartz fibers and their influence on the physicochemical properties and in vitro cell viability of dental composites.

ABSTRACT

OBJECTIVE: Although glass fibers are more common, quartz fibers (QFs) are also considered as the ideal reinforcing material in dentistry, due to their superior mechanical strength, high purity, and good photoconductive properties. However, the relatively inert surfaces limit their further applications. Therefore, the aim of this study is to modify the fiber surface properties to improve the interfacial interactions with polymeric resins. METHODS: In this study, we systematically introduced four different surface modification strategies onto short quartz fibers (SQFs) for the preparation of dental composites. Particularly, the acid etching was a facile way to create mechanical interlocking structures. In addition, the silanization process, the sol-gel treatment, and the polymer grafting were further proposed to increase the surface roughness and the reactive sites. The effect of surface modifications on the fiber surface morphological changes, mechanical properties, water stability, and in vitro cell viability of dental composites were investigated. RESULTS: Among all surface-modified SQFs, SQFs-POSS (SQFs modified with methacrylate-POSS) exhibited the roughest surface morphology and highest grafting rates compared with other three materials. Furthermore, all these SQFs were applied as reinforcements to make dimethacrylate-based dental resin composites. Of all fillers, SQFs-POSS demonstrated the best reinforcing effect, providing significantly higher improvements of 55.7 %, 114.3 %, and 164.7 % for flexural strength, flexural modulus, and breaking energy, respectively, over those of SQFs-filled composite. The related reinforcing mechanism was further investigated. The SQFs-POSS-filled composite also exhibited the best water stability performance and in vitro cell viability. SIGNIFICANCE: This work provided valuable insights into the optimization of filler-matrix interaction through fiber surface modifications. Specifically, SQFs-POSS markedly outperformed other formulations in terms of the physicochemical performance and in vitro cytotoxicity, which offers possibilities for developing high-performance dental composites for clinical applications in restorative dentistry.