Lenet B J, Komorowski R, Wu X Y, Huang J, Grad H, Lawrence H P, Friedman S
Endodontics Department, University of Toronto, Ontario, Canada.
J Endod. 2000 Nov;26(11):652-5. doi: 10.1097/00004770-200011000-00005.
Root canal dentin acquires antimicrobial substantivity after exposure to chlorhexidine gluconate (CHX) for 1 wk. Therefore development of a vehicle for delivery of CHX as an intracanal medication is desirable. This in vitro study assessed the efficacy of two CHX delivery vehicles, a controlled-release device and a gel, to affect antimicrobial substantivity of bovine root dentin. Sixty bovine incisor root specimens were prepared with standardized length (10 mm) and canal diameter (3.3 mm), and coated externally with nail polish. Specimens were divided into four equal groups and their canals medicated for 7 days with either: (i) an experimental controlled-release device containing 25% CHX that was immersed in sterile saline; (ii) 2% CHX gel; or (iii) Ca(OH)2 paste. Sterile saline was used as the positive control. After medication, the canals of the specimens were inoculated with Enterococcus faecalis for 21 days. Root canal dentin samples ranging in depth from 0.1 to 0.45 mm were then obtained using sterile round burs of ascending diameter. Each dentin sample was placed in a separate test tube containing Brain Heart Infusion broth and incubated for 24 h. The optical density (OD) of the broth was then measured spectrophotometrically at 540 nm. The positive control showed significantly higher mean OD values (one-way ANOVA and Tukey's Studentized Range Test; p < 0.001) than the three test groups. The CHX controlled-release device group showed significantly lower OD values than the Ca(OH)2 group; however only at dentin depths up to 0.2 mm. In contrast, the CHX gel group consistently showed significantly lower OD values than both the CHX controlled-release device and Ca(OH)2 groups. These results suggest that bovine root canals medicated with 2% CHX gel for 7 days acquire antimicrobial properties for at least 21 days.
根管牙本质在暴露于葡萄糖酸氯己定（CHX）1周后会获得抗菌持久性。因此，开发一种作为根管内药物递送CHX的载体是很有必要的。这项体外研究评估了两种CHX递送载体——一种控释装置和一种凝胶——对牛牙根牙本质抗菌持久性的影响。制备了60个具有标准化长度（10毫米）和根管直径（3.3毫米）的牛切牙根标本，并在外部涂上指甲油。标本被分成四组，每组数量相等，其根管用药7天，用药方式分别为：（i）一种含有25%CHX的实验性控释装置，该装置浸泡在无菌盐水中；（ii）2%CHX凝胶；或（iii）氢氧化钙糊剂。无菌盐水用作阳性对照。用药后，将粪肠球菌接种到标本的根管中21天。然后使用直径递增的无菌圆钻获取深度在0.1至0.45毫米之间的根管牙本质样本。每个牙本质样本被放置在一个单独的含有脑心浸液肉汤的试管中，并孵育24小时。然后在540纳米处用分光光度计测量肉汤的光密度（OD）。阳性对照的平均OD值显著高于三个测试组（单因素方差分析和Tukey氏学生化极差检验；p<0.001）。CHX控释装置组的OD值显著低于氢氧化钙组；然而，仅在牙本质深度达0.2毫米时如此。相比之下，CHX凝胶组的OD值始终显著低于CHX控释装置组和氢氧化钙组。这些结果表明，用2%CHX凝胶处理7天的牛根管至少在21天内具有抗菌性能。
