Preparation And Characterization Of Antimicrobia Light-cured Composite Resin

Light-cured composite resin, with excellent aesthetic and mechanical properties, has become the main material in dental restoration, especially widely used in tooth defect filling.. However, secondary caries caused by its lack of antibacterial properties is a major cause of failure in restoration. LZB-GC antibacterial agent is a silver base inorganic antibacterial agent with good antibacterial property. It is an important topic in clinic to explore how to add the antimicrobial inorganic filler into composite resin.In this study, we added0,0.5%,1%,1.5%and2%LZB-GC inorganic antibacterial agent into composite resin using the mechanical and ultrasonic dispersion. Dispersion degree of antibacterial agent was observed by scanning electron microscopy (SEM). The curing rate of modified composite resin (RC) with different proportion of inorganic antibacterial was determined by the Fourier transform infrared spectrometer (FTIR). Its antimicrobial property after curing is tested by bacteriostatic ring experiment. Flexural strength (FS), Surface hardness and Coefficient of friction (COF) were respectively detected by universal testing machine, UMT-2MT friction and wear tester, micro hardness tester. We discussed the effect of the different proportions of inorganic antibacterial agent on curing rate, the antibacterial and mechanical properties of composite resin, finding the best proportion of the LZB-GC inorganic antibacterial agent.The main results were as follows:(1) The LZB-GC inorganic antibacterial agent with different proportions was successfully mixed in composite resin, using mechanical and ultrasonic dispersion through, adding silane coupling agent. The surface particles dispersed evenly, observed by SEM.(2) FTIR determinate the change of C=C (1640cm-1) on the peak area before and after treatment of the composite resin. We obtained the early rate of curing. The results indicated that the addition of LZB-GC inorganic antibacterial agent did not result in the decrease of curing rate, but improvement in a certain extent.1%antibacterial agent could achieve the largest initial curing degree.(3) Bacteriostatic ring testing was carried out using streptococcus mutans. Results showed that all the modified composite resin exhibit obvious bacteriostatic ring after2weeks,1.5%bacteriostasis was the best. The bacteriostasis was reduced after eight weeks. The bacteriostasis of1%,1.5%,2%antibacterial composite resin remained relatively stable,0.5%was almost disappear during8～16weeks,(4) Mechanical properties testing illustrated that adding LZB-GC inorganic antibacterial agent will change the mechanical properties of composite resin. Flexural strength was significantly increased compared with the control group,1.5%(170.96MPa) was the highest, and it is two times higher than that of control group. Surface hardness was lower compared with control group. The more adding proportion, the greater fall in hardness will be observed.1%and1.5%were the minimum of falling range,0.5%and2%were the maximum of falling range. COF were higher compared with the control group,1.5%achieved the maximum COF (0.1639).