Jafarzadeh Hamid, Abbott Paul V
Department of Endodontics, Faculty of Dentistry and Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
J Endod. 2007 Oct;33(10):1155-62. doi: 10.1016/j.joen.2007.07.015. Epub 2007 Sep 4.
Failure to grasp the rationale behind cleaning and shaping concepts can increase the occurrence of needless complications, such as ledges. A ledge is created when the working length can no longer be negotiated and the original pathway of the canal has been lost. Extension of the access cavity to provide unobstructed access to the root canals, precurving and not forcing instruments, using NiTi files, using passive step-back and balanced force techniques, and instrumenting the canal to its full length will all help to prevent ledge formation. Initial negotiation and bypassing the ledge can be achieved using a small file with a distinct curve at the tip, whereas a slight rotation motion of the file combined with a ''picking'' motion can often help advance the instrument. A review of the literature and a discussion of the options for prevention, recognition and managing the ledge are presented.
未能理解根管清理和塑形概念背后的基本原理会增加诸如台阶等不必要并发症的发生几率。当工作长度无法再继续推进且根管的原有通道已丧失时,就会形成台阶。扩大开髓腔以确保能无阻碍地进入根管、对器械进行预弯而不是强行使用、使用镍钛锉、采用被动逐步后退和平衡力技术以及将根管预备至全长,所有这些都有助于防止台阶的形成。使用尖端有明显弯曲的小锉可以初步探查并绕过台阶,而锉的轻微旋转运动与“挑动”运动相结合通常有助于器械向前推进。本文对相关文献进行了综述,并讨论了预防、识别和处理台阶的各种方法。