模板法合成Ag-Zn-Ca-Si复合纳米介孔颗粒用于根管内感染控制的实验研究

Researches have revealed that the canal re-infection is responsible for over 60% of root canal treatment failure. The main reason for the canal re-infection is the incomplete removal of bacteria from the canal system. The routine canal mechanical preparation, chemical irrigation and intra-radicular medication are not able to eliminate the bacteria inside the canal isthmus and dentinal tubules. Besides, some dominant intra-radicular infectious bacteria, such as Enterococcus faecalis, have developed resistance against the most often used intra-radicular medication. Antibacterial metal ions, such as Ag+ and Zn2+, show a broad-spectrum anti-bacterial ability with no resistance phenomenon, but the Ag+ presents higher cytotoxicity than Zn2+. The nano-mesoporous particles containing Ca and Si elements present strong infiltration ability and could promote tissue mineralization. These nano-particles could be excellent carrier for antibacterial metal ions. Despite this, current studies are mostly using adsorption method to load a single type of metal ion onto materials. Adsorption method for loading a single type of metal ion could not provide a precise control on the amount of ions being loaded and employ the synergistic anti-bacterial effects by different types of ions. Comparatively, the template method for loading ions could produce a stable and controllable structure and component for the material. Based on these considerations, the main purposes for this study are to synthesize and select out the Ag-Zn-Ca-Si nano-mesoporous particles with the best Ag-Zn ratios using template method. These particles are expected be able to infiltrate into canal isthmus and dentinal tubules, non-cytotoxic, show good control effects for canal infection and can promote the healing of periapical diseases. The effective method for the application of Ag-Zn-Ca-Si nano-mesoporous particles in the canal infection control will be hopefully established.

超过60%的根管治疗失败与根管系统的再感染有关，而根管系统中感染微生物未彻底清除是导致再感染出现的主要原因。目前常规的器械切削、化学冲洗以及根管内放置消毒药物等都无法彻底去除根管狭区和牙本质小管的感染微生物。根管再感染优势菌粪肠球菌，对目前常用的根管内消毒药物具有耐药性。抗菌金属离子Ag+ 和Zn2+，广谱抗菌且无耐药现象，但Ag+毒性显著高于Zn2+。含Ca、Si元素的纳米介孔颗粒弥散渗透性好，且有助于组织矿化成骨，是抗菌金属离子的良好载体。但目前采用的吸附法无法准确控制携带离子的量，且无法发挥多种抗菌离子的协同抗菌作用。因此，本项目拟使用模板法合成并筛选出具有最佳Ag-Zn配比的Ag-Zn-Ca-Si纳米介孔颗粒，可望其具有高弥散渗透性、良好的生物相容性、良好的根管内感染控制能力，且能促进根尖周病变愈合，并建立应用该材料进行根管内感染控制的有效方法。

根管内残留的感染微生物是根管治疗失败的重要原因，利用纳米材料携带高效抗菌剂进行根管感染控制是目前的研究热点之一。本研究通过模板法合成了钙硅纳米介孔颗粒，其表面积高达300-600m2/g，颗粒内部有直径为2-4nm的孔道，可携带和缓释多种杀菌剂；同时，对不同银-锌配比溶液对粪肠球菌的抑菌能力进行了研究，确定了银锌原子比大于1:6是抗浮游态粪肠球菌和粪肠球菌生物膜的最优配比；在此基础上，制备了含银、锌优化配比的凝胶，发现其对牙本质片上的粪肠球菌生物膜具有良好的抗菌效果。基于以上研究结果，使用模板法合成了具有最有银锌配比的Ag-Zn-Ca-Si纳米介孔材料，并进行体外抗粪肠球菌实验，发现载有最优配比的Ag-Zn-Ca-Si纳米介孔材料抗菌效果最佳。最后，建立了比格犬的根管及根尖周感染模型，通过比较载有不同银锌配比Ag-Zn-Ca-Si纳米介孔材料在比格犬根管内抗粪肠球菌感染的效果，明确了载有最优配比Ag-Zn-Ca-Si纳米介孔材料能够有效的抑制根管及根尖周的感染，为临床根管治疗中加强根管系统的感染控制提供了新方法。