Chockattu Sherin Jose, Deepak B S, Goud K Mallikarjun
Department of Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital, Davangere, Karnataka, India.
Department of Conservative Dentistry and Endodontics, Dental College, RIMS, Imphal, Manipur, India.
J Conserv Dent. 2017 Jan-Feb;20(1):6-11. doi: 10.4103/0972-0707.209079.
Being integral to root canal therapy, obturation can be performed adequately only after the removal of intracanal medicament. One technique involves the use of chelating agents such as ethylenediaminetetraacetic acid (EDTA) and citric acid. Etidronic acid, a relatively new chelator, has smear layer removal ability and lesser dentinal erosion. It is untested in calcium hydroxide (Ca[OH]) medicament removal.
The aim of this study was to compare the efficiency of irrigation protocols (EDTA, citric acid, and etidronate) in Ca(OH) removal.
Forty-five single-rooted mandibular premolars were decoronated, instrumented, and filled with Ca(OH). After 7 days incubation, Ca(OH) was removed by three irrigation protocols (Group-I: 17% EDTA; Group-II: 10% citric acid; and Group-III: 18% etidronate). Roots were split and analyzed (scanning electron microscope, ×1500). Chelator solution pH was tested. Data were analyzed by Kruskal-Wallis ANOVA and Mann-Whitney U-test.
Group-III (coronal-third) and Groups-I and II (middle-third) had highest cleanliness scores; Groups-II and III (apical-third) had lowest scores. Comparing the thirds, all groups showed difference in scores. pH of Groups-I, II, and III were 6.8, 1.4, and 0.3, respectively.
The solution pH of citric acid and etidronate impacts their Ca(OH) removal efficiency in different ways: the highly alkaline pH of Ca(OH) increases citric acid pH toward neutrality, where it becomes an inefficient chelator; on the contrary, high acidity of etidronate compensates for its weaker chelation. Etidronate may not require 5 min duration for Ca(OH) removal due to the likelihood of dentinal erosion.
根管充填是根管治疗的重要组成部分，只有在去除根管内药物后才能进行充分的充填。一种技术涉及使用螯合剂，如乙二胺四乙酸（EDTA）和柠檬酸。依替膦酸是一种相对较新的螯合剂，具有去除玷污层的能力且对牙本质的侵蚀较小。它在去除氢氧化钙（Ca[OH]）药物方面未经测试。
本研究的目的是比较冲洗方案（EDTA、柠檬酸和依替膦酸盐）在去除Ca(OH)方面的效率。
45颗单根下颌前磨牙去冠、预备根管并充填Ca(OH)。孵育7天后，通过三种冲洗方案去除Ca(OH)（第一组：17% EDTA；第二组：10%柠檬酸；第三组：18%依替膦酸盐）。将牙根劈开并进行分析（扫描电子显微镜，×1500）。测试螯合剂溶液的pH值。数据通过Kruskal-Wallis方差分析和Mann-Whitney U检验进行分析。
第三组（冠三分之一）以及第一组和第二组（中三分之一）的清洁度评分最高；第二组和第三组（根端三分之一）的评分最低。比较各三分之一段，所有组的评分均有差异。第一组、第二组和第三组的pH值分别为6.8、1.4和0.3。
柠檬酸和依替膦酸盐的溶液pH值以不同方式影响其去除Ca(OH)的效率：Ca(OH)的高碱性pH值使柠檬酸的pH值向中性增加，此时它成为一种低效的螯合剂；相反，依替膦酸盐的高酸度弥补了其较弱的螯合作用。由于存在牙本质侵蚀的可能性，依替膦酸盐去除Ca(OH)可能不需要5分钟的时间。
