Grawehr M, Sener B, Waltimo T, Zehnder M
Department of Preventive Dentistry, Cariology, and Periodontology, University of Zürich Center for Dental Medicine, Zürich, Switzerland.
Int Endod J. 2003 Jun;36(6):411-7. doi: 10.1046/j.1365-2591.2003.00670.x.
To evaluate interactions of ethylenediamine tetraacetic acid (EDTA) with sodium hypochlorite (NaOCl).
Solutions consisting of 8.5% EDTA and 0.5% NaOCl were compared to a 1 : 1 (w/w) mixture of 17% EDTA and 1% NaOCl for their calcium-chelating, tissue-dissolving, and antimicrobial properties. Amounts of available chlorine were determined in the EDTA/NaOCl solutions with an iodine/thiosulphate titration method. Calcium chelation capacity was titrated with a pure calcium solution using a murexide indicator. Weight loss of porcine palatal mucosal specimens incubated in the test solutions was measured over time. Antimicrobial potential of pure solutions and the combination was recorded using an agar diffusion test in plates incubated with Enterococcus faecalis or Candida albicans.
The presence of hypochlorite had little effect on the calcium-chelating ability or on the antimicrobial potential of EDTA. Available chlorine content decreased to 0.06% in the combined EDTA-NaOCl solution compared to 0.50% in an equivalent NaOCl mixture with deionized water. The EDTA-NaOCl solution did not dissolve more tissue than an equivalent pure EDTA solution at any time (anova, P > 0.05).
Ethylenediamine tetraacetic acid retained its calcium-complexing ability when mixed with NaOCl, but EDTA caused NaOCl to lose its tissue-dissolving capacity and virtually no free chlorine was detected in the combinations. Clinically, this suggests that EDTA and NaOCl should be used separately. In an alternating irrigating regimen, copious amounts of NaOCl should be administered to wash out remnants of the EDTA.
评估乙二胺四乙酸（EDTA）与次氯酸钠（NaOCl）之间的相互作用。
将由8.5% EDTA和0.5% NaOCl组成的溶液与17% EDTA和1% NaOCl的1:1（w/w）混合物进行比较，考察它们的钙螯合、组织溶解和抗菌性能。采用碘/硫代硫酸盐滴定法测定EDTA/NaOCl溶液中的有效氯含量。使用紫脲酸铵指示剂，用纯钙溶液滴定钙螯合能力。测定猪腭黏膜标本在测试溶液中孵育后的随时间的重量损失。使用琼脂扩散试验记录纯溶液及其组合对粪肠球菌或白色念珠菌培养平板的抗菌潜力。
次氯酸盐的存在对EDTA的钙螯合能力或抗菌潜力影响很小。与含去离子水的等量NaOCl混合物中的0.50%相比，EDTA-NaOCl混合溶液中的有效氯含量降至0.06%。在任何时候，EDTA-NaOCl溶液溶解的组织都不比等量的纯EDTA溶液多（方差分析，P>0.05）。
乙二胺四乙酸与次氯酸钠混合时仍保留其钙络合能力，但EDTA会使次氯酸钠失去其组织溶解能力，并且在组合中几乎检测不到游离氯。临床上，这表明EDTA和次氯酸钠应分开使用。在交替冲洗方案中，应大量使用次氯酸钠以冲洗掉EDTA的残留。
