Ward Jeff R, Parashos Peter, Messer Harold H
Department of Endodontics, School of Dental Science, The University of Melbourne, Victoria, Australia.
J Endod. 2003 Nov;29(11):756-63. doi: 10.1097/00004770-200311000-00017.
The use of nickel-titanium rotary instruments in endodontic practice is increasing. One frequently mentioned problem is fracture of an instrument within the root canal. To date, there is no consistently safe and successful technique for removing these fractured instruments. This study evaluates the use of an ultrasonic technique to remove fractured rotary nickel-titanium instruments from narrow, curved canals in both simulated (resin blocks) and mesiolingual canals of extracted mandibular first molars. A technique using ultrasonic tips, combined with the creation of a "staging platform" and the use of the dental operating microscope, was consistently successful and safe at removing fractured rotary nickel-titanium instruments from curved root canals, when some part of the fractured instrument segment was located in the straight portion of the canal. When the fractured instrument segment was located entirely around the curve, the success rate was significantly decreased and major canal damage often occurred.
镍钛旋转器械在牙髓病治疗中的应用正在增加。一个经常被提及的问题是根管内器械折断。迄今为止，尚无一种始终安全且成功的技术来取出这些折断的器械。本研究评估了一种超声技术在模拟（树脂块）和拔除的下颌第一磨牙近中舌根管的狭窄、弯曲根管中取出折断的旋转镍钛器械的应用。当折断器械片段的一部分位于根管的直线部分时，一种使用超声头、结合创建“分级平台”和使用牙科手术显微镜的技术，在从弯曲根管中取出折断的旋转镍钛器械方面始终是成功且安全的。当折断器械片段完全位于弯曲处时，成功率显著降低，且常发生严重的根管损伤。
