Photodynamic antibacterial property of g-C3N4 formulated dental resin composite

The occurrence of secondary caries associated with the polymerization shrinkage of dental resin composite repairing is mainly due to the resin lacking of bacteria-killing ability to counteract bacterial colonization at the tooth-resin interface. Photodynamic therapy against bacterial infections paves a new way for developing novel antibacterial dental resin composites. Herein, a yellowish graphitic carbon nitride (g-C 3 N 4 ) is synthesized via thermal polycondensation of melamine and functions as photoactive filler for resin composites in oral application. Upon exposed to visible light, the g-C 3 N 4 would generate reactive oxygen species (ROS) to kill bacteria, that Staphylococcus aureus ( S. aureus ) and Streptococcus mutans ( S. mutans ) almost completely die within 30 min. As the g-C 3 N 4 mixed into photocurable bisphenol A glycidyl methacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) at 5 wt%, the resulted composite remains high S. aureus and S. mutans killing rates (> 99 %), even supplemented with extra 65 wt% Schott® dental glass powders. The mechanical properties and biocompatibility of the resin composite are not influenced with the addition of g-C 3 N 4 . Overall, this resin composite with excellent photodynamic antibacterial capacity displays significant potential for dental restoration application.