Reinforcement of Dental Composites With Novel Core-Shell Nanofibers Containing Matrix Resin Through Interface Modification

Considering the significant contribution of fillers-matrix interfacial adhesion to the mechanical characteristics of dental dimethacrylate resin composites, novel core-shell nanofibers containing matrix resin have been investigated as reinforcement for their excellent interfacial adhesion. The coaxial electrospinning was employed to fabricate the core-shell nanofibers using a mixture of bisphenol A-glycidyl methacrylate (BISGMA) and tri-(ethylene glycol) dimethacrylate (TEGDMA) as core fluid and polyacrylonitrile (PAN) solution as shell fluid. The primary aim was to analyze the flexural properties of BISGMA/TEGDMA composites reinforced with varying mass fractions (2.5%, 5%, and 7.5%) of these innovative core-shell nanofibers. The PAN solution with and without BISGMA/TEGDMA monomers was also electrospun through single-nozzle electrospinning. The morphology and tensile properties of electrospun nanofibers, besides the BISGMA/TEGDMA wetting properties of nanofibers, were investigated. BISGMA/TEGDMA contact angle measurements imply enhanced compatibility of core-shell nanofibers with the resin matrix. The encapsulation of monomers into the core-shell structure preserves the mechanical properties of nanofibers compared to neat PAN. In contrast, mixing monomers through the electrospinning solution deteriorates the tensile strength and modulus of nanofibers. The incorporation of BISGMA/TEGDMA-PAN core-shell nanofibers into the BISGMA/TEGDMA composite resulted in an enhanced flexural strength of 21.0%, 47.3%, and 40.5% for 2.5, 5, and 7.5 wt.%, respectively, in comparison to the neat resin. The results confirm that encapsulating BISGMA/TEGDMA monomers into nanofibers is valuable for significantly increasing the nanofibers-matrix interfacial adhesion.