超声技术在从根管中取出折断的旋转镍钛根管器械方面的成功及其对根管折断所需力的影响。

Success of ultrasonic technique in removing fractured rotary nickel-titanium endodontic instruments from root canals and its effect on the required force for root fracture.

机构信息

Kerman Oral and Dental Diseases Research Center, Kerman University of Medical Science, Kerman, Iran.

出版信息

J Endod. 2013 Jun;39(6):824-8. doi: 10.1016/j.joen.2013.02.008. Epub 2013 Apr 16.

DOI:10.1016/j.joen.2013.02.008

PMID:23683286

Abstract

INTRODUCTION

Fracture of rotary nickel-titanium files is a real concern among endodontists; it affects the long-term prognosis of treatment. Ultrasound is a favorable technique for removing broken files, although it may result in some complications. The aim of this study was to determine the success rate of ultrasonic technique in removing file fragments and to evaluate its influence on the force required to fracture a tooth root.

METHODS

An in vitro study was carried out on 70 extracted maxillary premolars. In the experimental group a #30/.04 taper Hero file was guided into the canal to break and lodge therein. The lodged file was removed by ultrasonic vibration and use of a dental operating microscope. The canals were instrumented with Hero files by using crown-down technique and then obturated. All the teeth were prepared for mechanical testing in Testometric machine to measure the required force for root fracture. The Fisher exact test and independent two-sample t test were used to analyze data.

RESULTS

Ultrasonic technique exhibited a success rate of 80% in removing broken files. Success rate in the roots with file fracture before the curve was 11.5 times more than that of file fracture cases beyond the curve. Other factors such as bypass possibility did not affect success rate. The average time required for removing file fragments was 36.3 ± 7.15 minutes, which did not significantly differ in different file locations within the canal. According to mechanical test results, ultrasonic application did not significantly affect the required force for root fracture. The force required to fracture a root did not significantly differ in various file locations. Vertical fracture in the buccolingual direction (split tooth) was the most incident fracture pattern. Procedural errors observed in this study predominantly included transportation, perforation, and craze line.

CONCLUSIONS

Ultrasonic technique was successful in removing 80% of fractured rotary files and did not significantly affect the required force for root fracture.

摘要

简介

根管锉折断是牙髓病医生非常关注的问题，它会影响治疗的长期预后。超声技术是取出折断器械的有利手段，但可能会带来一些并发症。本研究旨在确定超声技术取出根管内器械断片的成功率，并评估其对折断牙根所需力的影响。

方法

本研究为体外实验，共纳入 70 颗上颌前磨牙。实验组将 30/.04 锥度 Hero 根管锉折断并楔入根管，然后用超声振动和牙科手术显微镜取出折断器械。采用冠向下技术用 Hero 根管锉预备根管，然后进行根管充填。所有牙齿均在 Testometric 机器上进行机械测试，以测量折断牙根所需的力。采用 Fisher 确切检验和独立两样本 t 检验对数据进行分析。

结果

超声技术取出折断器械的成功率为 80%。在根管内未出现弯曲前折断器械的成功率是根管内出现弯曲后折断器械的 11.5 倍。其他因素，如旁路的可能性，不影响成功率。取出器械断片的平均时间为 36.3±7.15 分钟，在根管内不同器械位置之间无显著差异。根据机械测试结果，超声的应用对折断牙根所需力无显著影响。在不同器械位置，折断牙根所需力无显著差异。颊舌向垂直（牙裂）是最常见的折断模式。本研究中观察到的操作失误主要包括器械移位、穿孔和微裂纹。