Improving antibacterial performance of dental resin adhesive via co-incorporating fluoride and quaternary ammonium.

Objective: Aiming to achieve improved antibacterial performance for dental application, sodium fluoride (NaF) nanoparticles and photopolymerizable N,N-dodecylvinylimidazole (DCV) were co-introduced into the dental resin adhesive at different ratios.

Methods: The respective effect of NaF and DCV on adhesive curing kinetic, antibacterial activities against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Bacterial Flora of Human saliva (HSBF) were comprehensively evaluated. Then, the synergistic effects of NaF nanoparticles and DCV on adhesive performance were studied in terms of fluoride ion (F) release, antibacterial activity, hydrophilicity, surface potential, cytotoxicity, and bonding strength.

Results: DCV monomer could polymerize with other adhesive monomers without influencing C = C double conversion rate, while the addition amount of DCV would affect the hydrophilicity and bonding strength of the cured adhesives. The cationic quaternary ammonium group could reduce the burst release of negative F for the adhesive at a NaF/DCV ratio (1:1, 2%), hence achieving both non-contact and contact antibacterial activity in an extended term without causing cytotoxicity.

Conclusion: Mixing NaF nanoparticles and DCV into the dental resin adhesive can slow down the initial burst release of F and prolong the release-type antibacterial effect. The ionic interaction between F and quaternary ammonium groups, as well as, the effect of DCV on adhesive hydrophilicity, simultaneously influence the release behavior of F. Co-incorporation of quanternary ammonium and fluoride improves adhesive's antibacterial performance for dental application.

Clinical Significance: Incorporating both NaF nanoparticles and DCV into dental resin adhesive could provide an efficient strategy for dental restoration as well as the prevention of secondary caries.