Study On Resin-based Dental Restorative Materials With Dual Antibacterial Mechanism

At present, resin-based dental restorative materials play a role in dental restoration. But resin composites have not antibacterial effect, so large amounts of researches have been carried out developing antibacterial restorative materials. Antibacterial agents can be divided into three types:inorganic antibacterial agents, organic antibacterial agents and polymerizable antibacterial monomer. In recent years, the multiple antibacterial mechanisms of materials become the focus of the study. In this thesis, the dental resin polymer system was added silver antimicrobial agent and a quaternary ammonium antibacterial monomer to prepare dental restorative materials with strong bactericidal activity.Silver substituted hydroxyapatite (Ag/HAP) was prepared and characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy. Then polymerizable Quaternary Ammonium monomer MAE-MB (2-methacryloxylethyl myristylmethyl ammonium bromide) was synthesized and characterized by nuclear magnetic resonance spectroscopy and infrared spectroscopy. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of unpolymerized MAE-MB against gram-positive (S. aureus) and gram-negative (E. coli) bacteria were tested. Unpolymerized MAE-MB showed strong bactericidal activity against two strains of bacteria. The MIC value of MAE-MB ranged from 4.8 to 39.1μg/mL and the MBC value of MAE-MB ranged from 9.6 to 78.1μg/mL.The antibacterial properties of resin-based dental restorative materials containing antibacterial agents were tested. First, experimental resin specimens containing Ag/HA were prepared. And the zone of inhibition was tested by an immersion method. These results confirmed that resin specimens incorporating Ag/HAP have release-killing capacity. With the Ag/HAP leaching more Ag+, its antibacterial properties became stronger. Second, experimental resins containing MAE-MB were polymerized, and the antibacterial effects against E. coli and S. aureus were determined. The conclusion is that resin specimens containing MAE-MB have contact bacteria-killing capacity, and it showed strong bactericidal activity. Final, the two kinds of antibacterial agents (Ag/HAP and MAE-MB) were added to the resin system to prepare experimental resin specimens. The resin specimens'surface were coated and tested by E. coli and S. aureus. The antibacterial activities of the resins which contained two kinds of antibacterial agents were increased with the incorporated concentration increased. And these reins exert rapid and long-lasting antibacterial activity.