One-year water-ageing of calcium phosphate composite containing nano-silver and quaternary ammonium to inhibit biofilms

摘要

Dental composites are commonly used restorative materials; however, secondary caries due to bio?lm acids remains a major problem. The objectives of this study were(1) to develop a composite containing quaternary ammonium dimethacrylate(QADM),nanoparticles of silver(NAg), and nanoparticles of amorphous calcium phosphate(NACP), and(2) to conduct the ?rst investigation of the mechanical properties, bio?lm response and acid production vs water-ageing time from 1 day to 12 months.A 4 × 5 design was utilized, with four composites(NACP-QADM composite, NACP-NAg composite, NACP-QADM-NAg composite,and a commercial control composite), and ?ve water-ageing time periods(1 day, and 3, 6, 9, and 12 months). After each waterageing period, the mechanical properties of the resins were measured in a three-point ?exure, and antibacterial properties were tested via a dental plaque bio?lm model using human saliva as an inoculum. After 12 months of water-ageing, NACP-QADMNAg had a ?exural strength and elastic modulus matching those of the commercial control(P40.1). Incorporation of QADM or NAg into the NACP composite greatly reduced bio?lm viability, metabolic activity and acid production. A composite containing both QADM and NAg possessed a stronger antibacterial capability than one with QADM or NAg alone(Po0.05). The anti-bio?lm activity was maintained after 12 months of water-ageing and showed no signi?cant decrease with increasing time(P40.1). In conclusion, the NACP-QADM-NAg composite decreased bio?lm viability and lactic acid production, while matching the loadbearing capability of a commercial composite. There was no decrease in its antibacterial properties after 1 year of water-ageing.The durable antibacterial and mechanical properties indicate that NACP-QADM-NAg composites may be useful in dental restorations to combat caries.