Objective: This study aims to compare the efficiency of three kinds of microtube extraction devices, namely, instrument removal system (IRS), micro-retrieve and repair (MR&R) system, and MR&R system using modified microtube in removing separated instruments with different exposure lengths.
Methods: After a cross-section platform model was established, the IRS, MR&R, and MR&R modified microtube system with sidewall window reduced to 0.20 mm were used to retrieve various separated instrument models, and the differences in extraction effects were statistically analyzed by Chi-square test. The separated instrument models were divided into two groups: stainless steel and nickel-titanium instrument groups. In total, 23 instruments were tested for three times each.
Results: When the exposed length of separated instrument was 0.50 mm, the removal efficiency of the modified MR&R system group was significantly higher than those of the IRS and MR&R system groups (P<0.001). When the broken end of the fracture instrument was up to 1.00 mm, the success rates of the MR&R system and modified MR&R groups were significantly higher than that of the IRS group (P<0.01). No difference was observed among these three devices when the exposure length of separated instruments was 1.50 mm or higher.
Conclusions: The MR&R and modified MR&R systems have good removal effect when the exposed length of separated instrument is small.
目的 研究IRS和根管治疗并发症微处理（MR&R）系统分离器械提取装置以及改良微套管的MR&R系统，对不同暴露长度的分离器械模型的提取效果。方法 通过建立断面平台模型，制作不锈钢器械实验组和镍钛器械实验组共23种分离器械模型，使用IRS和MR&R系统及改良微套管的MR&R系统分别提取这些分离器械，每种器械提取3次，使用卡方检验分析其提取效果的差异。结果 当分离器械暴露为0.50 mm时，使用改良微套管的MR&R系统提取效果显著优于IRS及MR&R系统（P<0.001）；当分离器械暴露为1.00 mm时，提取镍钛分离器械时，2种MR&R系统提取效果显著优于IRS系统（P<0.01）；当分离器械暴露为1.50 mm以上时，三者无差异。结论 对暴露长度较短的分离器械，MR&R系统提取效果好，改良微套管的MR&R系统提取分离器械的成功率更高。.
Keywords: instrument removal system; instrument separation; micro-retrieve and repair system; microtube.