Novel Rechargeable Nano Calcium Phosphate Crown Cement Containing Antibacterial Monomer

Objectives: Resin cements with remineralizing and antibacterial properties are favorable for inhibition of caries. The objectives of this study were: (1) to investigate the capability of the novel dimethylaminohexadecyl methacrylate (DMAHDM) and nano-sized amorphous calcium phosphate (NACP) containing cement to reduce complex cariogenic biofilm models derived from human saliva, and (2) to investigate the long-term ion release, recharge, and re-release of DMAHDM-NACP resin-based crown cement.
Methods: NACP was integrated at a mass fraction of 25%. DMAHDM was added at 0%, 3%, and 5% mass fractions. Colony-forming units (CFU), lactic acid production, metabolic activities, and minimum inhibitory concentration (MIC) assays were performed. In addition, calcium (Ca) and phosphate (P) ion release, recharge, and re-release were assessed.
Results: Compared to experimental and commercial controls, the NACP-DMAHDM cement significantly reduced CFU biofilm by 2-3 orders of magnitude, metabolic activities from 0.24±0.06 A₅₄₀/cm² to 0.03±0.005 A₅₄₀/cm², and lactic acid production from 27±2 mmol/L to 5.4±2 mmol/L (n=6) (p<0.05). The DMAHDM antibacterial agent showed significant antibacterial potency, with an MIC value of 0.032 mg/L. However, when the DMAHDM was combined with the pyromellitic glycerol dimethacrylate (PMGDM) monomer, the MIC was greater than DMAHDM alone. The ion concentrations for the experimental groups significantly increased over time (1 to 84 days), indicating continuous ion release (n=3) (p<0.05). Increasing DMAHDM from 3% to 5% did not affect Ca-P ion release (p>0.05). All cement groups had continuous ion release after each recharge. Increasing the DMAHDM level from 0% to 5% and from 3% to 5% significantly enhanced ion recharge and re-release at the third cycle (p<0.05).
Conclusions: Incorporating DMAHDM-NACP into resin-based crown cement provides strong antibacterial action against multi-species biofilms and presents a high level of Ca and P ion recharge abilities, exhibiting long-term Ca and P ion release and remineralization potential.