Department of Endodontics, School of Dentistry, University of Washington, Seattle, WA 98195-7448, USA.
Int Endod J. 2012 Sep;45(9):878-82. doi: 10.1111/j.1365-2591.2012.02048.x. Epub 2012 Apr 6.
To determine if the formation of para-chloroaniline (PCA) can be avoided by using an alternative irrigant following sodium hypochlorite but before chlorhexidine.
Fifty-five single-rooted teeth were decoronated, instrumented to size 40, .06 taper whilst being irrigated with 14% ethylene-diamine-tetra-acetic acid (EDTA) and 6% NaOCl. Samples were then randomly divided into three experimental and two control groups. Group 1 was irrigated with saline followed by 2% chlorhexidine gluconate (CHX). Group 2 was irrigated with 50% citric acid (CA) followed by 2% CHX. Group 3 was irrigated with 14% EDTA followed by 2% CHX. The chemical identity and quantification of the PCA in the formed precipitate was determined using gas chromatography/mass spectrometry (GC/MS).
All experimental groups contained PCA. The mean level of PCA for group 1 (sterile saline) was 229 ng mL(-1), group 2 (citric acid) 72 ng mL(-1) and group 3 (EDTA) 400 ng mL(-1), respectively. A significant difference was found between the saline and EDTA groups and the negative control (P < 0.05). Although no statistical significance was found between the negative control and citric acid group, PCA was still present in this experimental group.
Citric acid used as the intermittent irrigant had the least amount of PCA formation in the canal system. Until the threshold required to cause biological damage in humans is determined, the combination of NaOCl and CHX in root canal treatment should be avoided.
确定在使用次氯酸钠后、氯己定之前，使用替代冲洗液是否可以避免形成对氯苯胺（PCA）。
55 颗单根牙被去冠，用 14%乙二胺四乙酸（EDTA）和 6%次氯酸钠冲洗至 40 号、0.06 锥度，然后将样本随机分为三组实验组和两组对照组。第 1 组用生理盐水冲洗，再用 2%葡萄糖酸氯己定（CHX）冲洗。第 2 组用 50%柠檬酸（CA）冲洗，再用 2% CHX 冲洗。第 3 组用 14% EDTA 冲洗，再用 2% CHX 冲洗。使用气相色谱/质谱联用仪（GC/MS）测定形成沉淀中 PCA 的化学性质和定量。
所有实验组均含有 PCA。第 1 组（无菌生理盐水）PCA 的平均水平为 229ng/ml，第 2 组（柠檬酸）为 72ng/ml，第 3 组（EDTA）为 400ng/ml。生理盐水和 EDTA 组与阴性对照组之间存在显著差异（P<0.05）。虽然柠檬酸组与阴性对照组之间无统计学意义，但该实验组仍存在 PCA。
柠檬酸作为间歇性冲洗液，在根管系统中形成的 PCA 最少。在确定引起人类生物损伤的阈值之前，应避免在根管治疗中同时使用次氯酸钠和氯己定。
