Laboratory study on AgNPs-modified 4-META/MMA-TBB resin as an antibacterial adhesive for root fracture reattachment

This study incorporated silver nanoparticles (AgNPs) into 4-META/MMA-TBB resin to develop an antibacterial adhesive for reattaching fractured roots with periodontal infections, using metronidazole (MNZ)-modified resin as control. The antibacterial effects against two oral bacteria were assessed using Plate Count and Scanning Electron Microscopy. The biocompatibility was evaluated with Cell Counting Kit-8 assay and live/dead cells staining. The bonding performance was evaluated using bovine vertical root fracture models by measuring the fracture resistance of roots reattached with experimental materials ( n = 20). Data were analyzed via one-way ANOVA and Tukey's test ( α =0.05). AgNPs-containing composites showed >99% antibacterial inhibition, outperforming MNZ-containing composites. 1.0/5.0 wt% AgNPs and 1.0 wt% MNZ groups showed biocompatibility similar to unmodified resin. AgNPs incorporation did not impair the fracture resistance of roots reattached with 4-META/MMA-TBB resin, whereas MNZ reduced it dose-dependently. AgNPs-modified 4-META/MMA-TBB resin is a promising antibacterial adhesive to improve the outcomes of root fracture reattachment.