Sustained Antibacterial Effect and Wear Behavior of Quaternary Ammonium Contact-Killing Dental Polymers after One-Year of Hydrolytic Degradation

This study intended to investigate the long-term antibacterial effect, mechanical performance, and surface topography of new anticaries dental composites. While most artificial aging studies resins lasted for 30–90 days, this prolonged water-aging one year be more clinically relevant. The base resin was loaded with dimethylaminohexadecyl methacrylate (DMAHDM) at 3 or 5 wt.% nano-sized amorphous calcium phosphate (NACP) 20 wt.%. Composites were subjected one-year water storage wear. Following aging, samples evaluated flexural strength, elastic modulus, microbiological assays. Biofilm plate counting method, metabolic assay, colorimetric quantification lactic acid, Baclight bacterial viability assay measured after year. Topography changes (ΔRa, ΔRq, ΔRv, ΔRt) examined wear observed by scanning electron microscopy. assays data analyzed via one-way ANOVA Tukey’s tests. Mechanical properties normalized verified using a t-test. strength values formulations that contained 5% DMAHDM-20% NACP, 3% DMAHDM, DMAHDM reduced significantly (p < 0.05) in relation baseline but still above ISO standards. No significant differences between groups concerning changes, except ΔRt, where there increase NACP group. All demonstrated robust biofilm-inhibition, slightly following aging. aged total microorganisms, streptococci, mutans streptococci 1.5 3-log, compared experimental control. containing able sustain performance affected over time.