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目的:体外观察不同光敏剂浓度和不同激光能量密度的TBO-PDT抑制离体牙根管内粪肠球菌的效果,确定最佳光敏剂参数和激光参数,并在此基础上探讨TBO-PDT在抑制离体牙根管内粪肠球菌上的作用优势,为PDT应用于根管消毒的临床实践提供理论与实验依据。方法:对离体牙进行根管预备,接种粪肠球菌,厌氧培养21d后建立粪肠球菌感染根管模型。将其随机分组:A组为阴性对照组,以生理盐水冲洗根管;B组为阳性对照组,以5.25%NaClO冲洗根管;其余组别根据光敏剂浓度的不同,分为C1组80μg/mL、D1组90μg/mL、E1组100μg/mL、F1组110μg/mL、G1组120μg/mL,避光孵育5min后用波长为630nm功率密度为90mW/cm2半导体激光在根管内上下提拉螺旋照射90s;根据光照时间的不同,分为C2组30s、D2组60s、E2组90s、F2组120s、G2组150s,光敏剂浓度为100μg/mL避光孵育5min后,用波长为630nm功率密度为90mW半导体激光在根管内上下提拉螺旋照射各实验组牙标本,实验处理前后即刻取样,厌氧培养24h,计数平板菌落,明确实验处理前后根管内粪肠球菌的数量变化。结果:(1)不同光敏剂浓度下TBO-PDT对根管内粪肠球菌抑菌效果的影响。平板菌落计数结果显示:不同光敏剂浓度的各组抑菌率随光敏剂浓度的增加而增高。与阴性对照组相比,C1组、D1组、E1组、F1组和G1组的抑菌率显著提高,而F1组和G1组两组间抑菌率没有明显差异。(2)不同光照时间对TBO-PDT抑制实验根管内以生物膜形式存在的粪肠球菌的抑菌效果。平板菌落计数结果显示:不同光照时间的各组抑菌率随光照时间延长而增高。与阴性对照组相比,其中C2组、D2组、E2组、F2组和G2组的抑菌率明显升高,而F2组和G2组两组间抑菌率没有明显差异。结论:TBO-PDT对以生物膜形式存在的粪肠球菌有明显的抑制作用,实验证实TBO-PDT最佳光敏剂浓度为110μg/mL,最佳光照时间为120s。
OBJECTIVE: To observe the inhibitory effect of TBO-PDT with different photosensitizer concentrations and different laser fluences on Enterococcus faecalis in vitro and to determine the optimal photosensitizer parameters and laser parameters. Based on this, the effects of TBO-PDT The role of root canal in E. faecalis role for the clinical application of PDT in root canal disinfection to provide theoretical and experimental basis. Methods: Root canal preparation was performed in vitro. Enterococcus faecalis was inoculated into the root canal of E. faecalis after anaerobic culture for 21 days. Group A was a negative control group, the root canal was washed with saline; the group B was a positive control group, the root canal was washed with 5.25% NaClO; the other groups were divided into C1 group 80μg / mL, D1 group 90μg / mL, E1 group 100μg / mL, F1 group 110μg / mL, G1 group 120μg / mL, incubated in the dark for 5min with a wavelength of 630nm power density of 90mW / cm2 semiconductor laser up and down the root canal According to the illumination time, the cells were divided into C2 group, 30s, D2 group, 60s, E2 group, 90s, F2 group, 120s and G2 group for 150s. The concentration of photosensitizer was 100μg / The density of 90mW semiconductor laser in the root canal up and down the spiral extraction of the experimental group of dental specimens, samples were taken immediately before and after the experiment, anaerobic culture 24h, count plate colonies, a clear experimental treatment before and after the number of Enterococcus faecalis changes. Results: (1) Effect of TBO-PDT on bacteriostasis of Enterococcus faecalis in root canal under different photosensitizer concentrations. The results of plate colony counting showed that the antibacterial activity of each group with different photosensitizer concentrations increased with the increase of photosensitizer concentration. Compared with the negative control group, the antibacterial rate of Group C1, D1, E1, F1 and G1 increased significantly, while there was no significant difference between F1 and G1. (2) The inhibitory effect of TBO-PDT at different light time on the bacteriostasis of Enterococcus faecalis with biofilm in experimental root canal. The results of plate colony counting showed that the antibacterial activity of each group increased with the increase of light time at different illumination time. Compared with the negative control group, the inhibitory rates of C2, D2, E2, F2 and G2 were significantly increased, while there was no significant difference between F2 and G2. CONCLUSION: TBO-PDT has a significant inhibitory effect on the presence of Enterococcus faecalis in the form of biofilm. The optimal photosensitizer concentration of TBO-PDT was 110μg / mL and the optimal illumination time was 120s.