Mehrvarzfar Payman, Akhlagi Nahid Mohammadzade, Khodaei Fatemeh, Shojaee Golnaz, Shirazi Sara
Department of Endodontics, Dental branch, Islamic Azad University, Tehran, Iran.
Dent Res J (Isfahan). 2014 Mar;11(2):251-6.
Management of canal isthmus is considered as an important factor for successful endodontic treatment. Accordingly, this study was designed to determine the prevalence, location, and types of isthmus in mesial root canals of extracted mandibular molars in a sample of Iranian population.
In this cross-sectional descriptive study, 60 extracted molars with two mesial canals were included. The samples were initially decoronated and then, roots were sectioned horizontally at 2, 4, and 6 mm levels from the apex via a low-speed handpiece with a thin metallic disk and finally prepared and stained with Indian ink. All sections were examined using a stereomicroscope at a magnification of ×30. Prevalence, location, and types of isthmus were evaluated based on the classifications by Kim and Teixeira and all data were statistically analyzed by the chi-squared test. The statistical significance level was established at 0.05.
Eighty-three percent of extracted mandibular molars had an isthmus at the mesial root. This prevalence increased with distance from the apex, that is, 92% at 6 mm from the apex and 70% at 2 mm from the apex. A statistically significant difference was found between the sections at 2 and 6 mm from the apex (P < 0.05), but no other significant differences between other levels (P > 0.05).
Isthmus is very common in the mesial roots of the mandibular permanent molars in the Iranian population, with the highest prevalence in the 6 mm distance from the root apex. Therefore, detection, cleaning, and filling of these apical 6 mm isthmuses are of great benefit in modern endodontics.
根管峡部的处理被认为是牙髓治疗成功的一个重要因素。因此，本研究旨在确定伊朗人群样本中拔除的下颌磨牙近中根管峡部的发生率、位置和类型。
在这项横断面描述性研究中，纳入了60颗有两条近中根管的拔除磨牙。样本首先去除牙冠，然后使用带有薄金属盘的低速手机从根尖分别在2mm、4mm和6mm水平进行水平切片，最后用印度墨水进行制备和染色。所有切片均在放大30倍的体视显微镜下检查。根据Kim和Teixeira的分类评估峡部的发生率、位置和类型，所有数据均采用卡方检验进行统计学分析。统计学显著性水平设定为0.05。
83%的拔除下颌磨牙近中根存在峡部。这种发生率随着与根尖距离的增加而升高，即距根尖6mm处为92%，距根尖2mm处为70%。在距根尖2mm和6mm处的切片之间发现有统计学显著差异（P < 0.05），但其他水平之间无其他显著差异（P > 0.05）。
峡部在伊朗人群下颌恒磨牙近中根中非常常见，在距根尖6mm处发生率最高。因此，在现代牙髓病学中，对这些根尖6mm峡部的检测、清理和充填具有很大益处。
