3D-printed resins used in occlusal splints modified with graphene nanoplatelets

This research focused on incorporate nanoparticles though sonification of the liquid 3D printing resin used in occlusal splints in the CAD-CAM process. It was evaluated the mechanical characteristics and cytotoxic effects of polymethylmethacrylate (PMMA) resin enhanced with graphene nanoplatelets (GNP at 0.125%, 0.250%, and 0.500% w/w) utilizing the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The flexural strength and modulus did not significantly change with GNP incorporation with exception of 0.500% composite, in which a reduction of similar to 50% for both properties was observed. The impact resistance showed the same trend but with a reduction of similar to 75% for 0.500% composite. In tensile strength, the unmodified PMMA sample exhibited superior resistance, which diminished progressively with higher GNP concentrations until a maximum of 20% reduction with high GNP concentration. The Shore D hardness test revealed a notable reduction at 0.125%, whereas higher concentrations (0.250% and 0.500%) led to the same results of the neat resin. All samples demonstrated favorable wettability with water. Composites with GNP concentrations of 0.125% and 0.500% were found to be cytotoxic, resulting in cell viability below 70%. Furthermore, the incorporation of graphene enhanced the hydrophilicity of the material, creating a surface barrier that inhibited bacterial proliferation. Finally, despite the promising prospects of graphene in dentistry, several challenges remain that must be overcome before these materials can achieve full commercialization for other applications as bone tissue engineering, coatings for dental implants, antibacterial functionalities, and collagen membranes.