| Objective: Plaque biofilm in the oral cavity is easy to accumulate on the surface of composite resin prosthesis,causing secondary caries and affecting the clinical long-term effect of restorations.The purpose of this experiment was to introduce nano-Mg O,an inorganic antibacterial agent,into the light-curing composite resin commonly used in dentistry,and to study the influence of the modified composite resin on human saliva microcosm biofilm,as well as their magnesium ion release performance and biocompatibility,which will lay a foundation for further research.Methods: In this study,bisphenol-A diglycidyl methacrylate(Bis-GMA)and triethylene glycol dimethacrylate(TEGDMA)were used as the matrix resin,camphorquinone(CQ)and 2-(dimethylamino)ethyl methacrylate(DMAEMA)as binary photo-initiated system,which were mixed with 78wt% surface-modified silica(Si O2)inorganic filler and nano-Mg O inorganic antibacterial agent to prepare experimental composite resins.According to the mass fraction of nano-Mg O in the filler,the experimental composite resins were divided into 6 groups: A0 = 0%,A1 = 1%,A2 = 2%,A3 = 5%,A4 = 10%,A5 = 15 %,among which A0 was the control group.An in vitro human saliva microcosm biofilm model was established,and the effect of experimental resins on it was evaluated by colony counting and live/dead bacteria staining methods.The release rule of magnesium in the experimental resin was explored by immersing the experimental resin samples in ultrapure water and measuring the content of magnesium ion in each group's leach solution with magnesium test kit on the 1d,3d,5d,7d and 28 d day,respectively.The extracts of each group of experimental resin were prepared,and co-cultured with the mouse fibroblasts L929 for 1d,3d,and 5d,the cytotoxicity were detected by methyl thiazolyl tetrazolium colorimetry(MTT)and live/dead cell staining.The experimental results were expressed as?x ± s,and processed by SPSS 23.0 statistical software.The significance of the difference among multiple groups was tested by one-way analysis of variance,and the pairwise comparison was performed by LSD-t test.Results: 1.Compared with the control group,group A2,A3,A4 and A5 had significant inhibitory effect on the growth of human saliva microcosm biofilm,showing an excellent antibacterial performance(P < 0.05).2.In addition to the first day,at all other detection time points,the concentration of magnesium ions released by the composite resin in each experimental group was significantly higher than that in control group(P < 0.05),and the release of magnesium ion in the group A4 and A5 was higher than that in the other experimental groups.3.In addition to the cytotoxicity of the extracts of group A2 and A4 in the 5d culture was grade 2,the cytotoxicity of the extracts in the other groups were grade 1.Moreover,compared with the control group,the cell morphology of each experimental group did not change significantly.Conclusions: 1.When the mass fraction of inorganic antibacterial agent nano-Mg O reached 2%,5%,10% and 15%,the composite resin had strong anti-plaque biofillm activity.2.Nano-Mg O modified composite resin could release magnesium ions in water solution slowly,and the magnesium ions released by 10% and 15% nano-Mg O containing composite resin could maintain a high level for a certain period of time.3.The cytotoxicity grade of composite resin containing nano-Mg O met the evaluation criteria and had good biocompatibility. |
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