Analysis of Electronic Apex Locators in Human Teeth Diagnosed With Apical Periodontitis

Abstract Electronic apex locators (EAL) have been used to establish the working length (WL) in root canal treatment. In teeth diagnosed with apical periodontitis, resorption of tooth apical structures can lead to difficulties to obtain an appropriate WL. The aim was to compare the capacity of three EAL’s (Root ZX II, Raypex 6 and Endo-Eze Quill) to locate the tip of the K-file between 0 to -0.5 mm from the apical foramen (AF) on teeth diagnosed with asymptomatic apical periodontitis (AAP). Electronic working length was performed on 60 roots with AAP. A K-file #15 was inserted in the root canal until the apical foramen (AF) was located, and followed was re-adjusted to -0.5 mm through observation in EAL display. The K-file was fixed to the tooth with composite and teeth were extracted. The 4 apical millimeters were worn out until the K-file could be seen and were prepared and measured its distance to AF in a scanning electron microscope. Appropriate WL was when the tip of the K-file was located between 0 to -0.5 mm from AF. Results: Root ZX II showed significant difference (p<0.01) with the other two EALs. Root ZX II presented the better performance than Raypex 6 or Endo-Eze Quill in teeth with AAP.

摘要：电子根尖定位仪（Electronic apex locators, EAL）已被应用于根管治疗中确定工作长度（working length, WL）。针对确诊为根尖周炎的患牙，其根尖结构的吸收会增加获取适宜工作长度的难度。本研究旨在对比三款电子根尖定位仪（Root ZX II、Raypex 6及Endo-Eze Quill）在确诊为无症状根尖周炎（asymptomatic apical periodontitis, AAP）的患牙中，定位K型锉尖端与根尖孔（apical foramen, AF）间距处于0至-0.5 mm范围内的能力。
本研究对60颗确诊为无症状根尖周炎的患牙根尖实施电子工作长度测定操作：将15号K型锉插入根管直至定位根尖孔，随后通过电子根尖定位仪显示屏将锉尖调整至距根尖孔-0.5 mm的位置，使用复合树脂将K型锉固定于患牙后拔除患牙。将根尖端4mm区域磨除直至K型锉完全暴露，通过扫描电子显微镜制备样本并测量其与根尖孔的间距。当K型锉尖端与根尖孔间距处于0至-0.5 mm范围内时，判定为工作长度适配。
结果显示，Root ZX II与其余两款电子根尖定位仪相比存在显著统计学差异（p<0.01），在无症状根尖周炎患牙中，Root ZX II的定位性能优于Raypex 6与Endo-Eze Quill。