Nano-antibacterial strategy for durable restoration: Optimized MgO-loaded adhesive resins combat biofilm formation

During process of light-curing, dental adhesives develop internal stresses that compromise marginal integrity, leading to microbial infiltration and subsequent biological and mechanical complications. To mitigate this, we developed an antibacterial light-curing adhesive resin by incorporating magnesium oxide nanoparticles (MgONPs) and systematically evaluated its performance. At 2 wt% MgONPs loading, the adhesive demonstrated antibacterial activity against Streptococcus mutans (S. mutans) with a 94.10 % inhibition ratio, while maintaining comparable mechanical properties and bond strength. Material characterization showed an overall increase in water absorption and film thickness with increasing MgONPs ratio. Cytotoxicity assays confirmed biosafety for all groups. The optimal MgONPs ratio was identified as 1–2 wt%, achieving effective antibacterial functionality without compromising critical material properties. The study provides a viable strategy for developing durable antibacterial dental adhesives through nanomaterial integration, showing promise for preventing recurrent decay and enhancing clinical durability.