Department of Endodontics, School of Dentistry, Loma Linda University, Loma Linda, California 92350, USA.
J Endod. 2010 Mar;36(3):520-3. doi: 10.1016/j.joen.2009.12.005.
The purpose of this investigation was to determine the concentration of sodium hypochlorite and the irrigation time required to disinfect dentin cylinders infected with Enterococcus faecalis.
Four hundred fifty dentin cylinders (5 mm in diameter and 4 mm in height) with a lumen (2-3 mm in width) were prepared from freshly extracted bovine incisors. The cementum and predentin were then removed. The tubules were opened by using a 4-minute application with 17% ethylenediaminetetraacetic acid and 5.25% NaOCl and then exposed to E. faecalis (ATCC 4082) for 3 weeks in brain-heart infusion broth. The cylinders were then divided into 3 groups, and a 1.3%, 2.5%, or 5.25% concentration of NaOCl was applied in 5-, 10-, 15-, 20-, 25-, 30-, 35-, and 40-minute intervals for a total of 30 subgroups including positive and negative controls. Each test sample was placed into a tube of 2 mL brain-heart infusion broth and incubated for 72 hours. Absence of turbidity demonstrated no bacterial growth, whereas turbidity indicated presence of remaining viable bacteria.
The most effective irrigation regimen was 5.25% at 40 minutes, whereas irrigation with 1.3% and 2.5% NaOCl for this same time interval was ineffective in removing E. faecalis from infected dentin cylinders.
High concentration and long exposure to NaOCl are needed for elimination of E. faecalis contaminated dentin.
本研究旨在确定次氯酸钠的浓度和冲洗时间，以消毒感染粪肠球菌的牙本质圆柱。
从新鲜提取的牛切牙中制备 450 个牙本质圆柱（直径 5mm，高 4mm，内腔宽 2-3mm）。然后去除牙骨质和前期牙本质。用 17%乙二胺四乙酸和 5.25%次氯酸钠处理 4 分钟以打开小管，然后将小管暴露于脑心浸液肉汤中的粪肠球菌（ATCC 4082）3 周。然后将圆柱分为 3 组，用 1.3%、2.5%或 5.25%的次氯酸钠分别在 5、10、15、20、25、30、35 和 40 分钟的间隔内冲洗 30 个亚组，包括阳性和阴性对照。每个测试样本都被放入 2 毫升脑心浸液肉汤的管中并孵育 72 小时。无混浊表示无细菌生长，而混浊则表示仍有存活细菌。
最有效的冲洗方案是 5.25%浓度 40 分钟，而在相同时间间隔内用 1.3%和 2.5%次氯酸钠冲洗则无法从感染的牙本质圆柱中去除粪肠球菌。
需要高浓度和长时间暴露于次氯酸钠以消除污染的牙本质中的粪肠球菌。
