PAN core-PMMA shell nanofiber fabric was prepared by electrospinning of polymer blends to reinforce 2,2 bis-[4-(methacryloxypropoxy)-phenyl]-propane (Bis-GMA) a dental resin system. The core-shell structure of the PAN-PMMA nanofiber was confirmed by scanning electron microscopy (SEM) and transmission electron microscope/energy dispersive spectroscopy (TEM/EDS) observation. The flexural properties and dynamic mechanical properties of the PAN-PMMA nanofiber reinforced Bis-GMA composites were studied. Results showed that PMMA shell was partly dissolved with the Bis-GMA resin. After photopolymerization, liner PMMA chains interpenetrated and entangled with the dental resin network, which resulted in an in situ nano-interface in the shell structure. Improvement of the mechanical properties of the PAN-PMMA nanofiber reinforced Bis-GMA composites has been achieved through this nano-interface formation. (C) 2008 Elsevier Ltd. All rights reserved.