Core–Shell-Structured Piezoelectric Inorganic Fillers Developed for Antibacterial Dental Resin Composites

Abstract One persistent challenge for dental restorations using photocurable resin composites is the occurrence of secondary caries associated with resin polymerization shrinkage. Resin composites with high antibacterial activity can be a solution to tackle this challenge. Piezoelectric materials showed long-term potential for killing bacteria due to their surface charge distribution and catalytic effect on the reactive oxygen species (ROS) generation under external mechanical stimulation. Herein, a kind of core–shell-structured filler (BAG@BT) was synthesized by coating dental glass powder (BAG) with piezoelectric barium titanate (BT), which is able to produce rich ROS and kill both Staphylococcus aureus (S. aureus) and Streptococcus mutans (S. mutans) with high efficiency (>99%). Unlike the resin composite cofilled with 30% BAG powder and 30% BT nanoparticles (bacteria-killing rate <50%), the resin composite containing 60% BAG@BT particles retained strong antibacterial activity (bacteria-killing rate >99%), as the BT phase had a larger surface area in the latter case. Compared to the resin composite filled with 60% BAG powder, the BAG@BT filler-formulated resin composite displayed similar flexural properties while promoting biomineralization. Conclusively, the core–shell-structured piezoelectric BAG@BT particles can function as antibacterial fillers for dental resin composites without compromising other performances for oral application, offering a promising strategy to cope with dental caries.