水中浸泡对自修复抗菌复合树脂性能影响的实验研究

目的 合成新型牙科自修复抗菌复合树脂,并探讨水中浸泡对其相关性能的影响。方法 在前期研究的基础上,制备含牙科自修复单体三乙二醇二甲基丙烯酸酯的微胶囊,以7.5%的质量百分比添加到含长链烷基季铵盐修饰的纳米抗菌二氧化硅填料的复合树脂中,生成自修复抗菌复合树脂,并以商品化的Tetric N-Ceram纳米瓷化复合树脂作为对照。复合树脂试件在37 ℃蒸馏水中浸泡处理不同时间,用三点弯曲试验来检测其力学性能;用单刃V形切口梁法来测试其断裂韧性及自修复效率;建立人牙菌斑生物膜体外模型,通过菌落计数、乳酸代谢分析等手段来评价其抗菌性能。结果 浸泡30 d后,对照组和实验组所有复合树脂力学性能及断裂韧性下降明显（P<0.05）,而后随着浸泡时间的延长,下降不明显（P>0.05）;水浸泡处理对自修复效率没有明显影响（P>0.05）,浸泡270 d后仍然可以获得64%的自修复效率;随着浸泡时间的延长,与对照组相比,实验组复合树脂对人牙菌斑生物膜的代谢仍然可以产生明显的抑制作用（P<0.05）,而实验组各时间段之间菌落计数及乳酸产生量则没有明显差异（P>0.05）,显示出良好的抗菌性能。结论 水中浸泡可以明显影响自修复抗菌复合树脂的力学性能,而自修复特性及抗菌性能则没有明显的变化。

Effect of water immersion on a dental self-healing and antibacterial resin composite

Objective This investigation aimed to develop a novel self-healing and antibacterial dental resin composite. The effects of water immersion on its properties were also evaluated. Methods Microcapsules filled with healing agent of triethylene glycol dimethacrylate were synthesized on the basis of previous studies. Antibacterial resin composite contained nano-antibacterial inorganic fillers that were modified by quaternary ammonium salt with long-chain alkyl. Microcapsules were incorporated into antibacterial resin composite at mass fraction of 7.5%. A commercial resin composite named Tetric N-Ceram was used as control. The resin samples were immersed in 37 °C distilled water for different periods. A flexural test was used to measure the mechanical properties of the novel resin composite. A single-edge V-notched beam method was used to measure fracture toughness and self-healing efficiency. A dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming units (CFU) and lactic acid production of biofilm on the novel resin composite were calculated to test the antibacterial property. Results Mechanical properties and fracture toughness decreased significantly after the composite was immersed in water for 30 days (P<0.05), and no significant reduction was found from then on (P>0.05). Water immersion did not weaken the self-healing capability of the composite (P>0.05), and self-healing efficiency of 64% could still be obtained even after 270 days. The antibacterial resin composite showed a strong inhibition effect on the biofilm metabolic activity versus water immersion time from 1 day to 270 days. Therefore, the com-posite could still have a promising antibacterial property even after being immersed in water (P<0.05). Conclusion Water immersion could weaken the mechanical properties of the novel self-healing and antibacterial resin composite, but it insig-nificantly affected the self-healing and antibacterial properties of the composite.