Near–infrared light–cured dental restoration materials with upconversion nanoparticles

Development of light–cured dental restoration materials with superior tissue penetration and mechanical properties is of paramount significance for treating oral diseases such as dental caries, which are among the most prevalent diseases globally. Herein, we report near–infrared (NIR) light–cured dental restoration materials with judiciously designed upconversion nanoparticles (UCNPs) as NIR-to-UV/Vis light nanotransducers. 808 nm NIR light-driven photopolymerization of methacrylate-thiol-ene resin materials is demonstrated, a photocuring depth of more than 11 cm is obtained for the resulting resin, and a NIR photocuring depth of more than 5 mm can be still achieved in the resin composite materials with 40 wt% SiO2 nanofillers. Importantly, the as-proposed dental restoration materials are found to exhibit superior mechanical properties, which can be comparable with commercial dental resin composites that are photocured by blue light. The in vitro and in vivo biocompatibility of the resulting materials was evaluated, and NIR light-driven restoration of the extracted teeth from periodontal or orthodontic patients was performed. This research can pave an avenue for NIR dental restoration chemistry and its widespread applications in biomedical science.