AIM To evaluate the viability of the electrochemical dissolution of fragments of fractured NiTi instruments in root canals of extracted human maxillary molars, using two electrodes and the solution restricted to a small reservoir coupled to the pulp chamber. The primary hypothesis was that this method enables the reduction of fragment volume and re-establishment of the root canal path with a size 08 K-file, both in simulated canals and in extracted human maxillary molars. METHODOLOGY Fragments of F1 ProTaper instruments were polarized in simulated root canals and in distobuccal root canals of extracted maxillary molars using a new method, with the solution restricted to a small acrylic microcell coupled to each resin block or pulp chamber. Two electrodes were used, where one was kept in contact with the intracanal fragment and another was positioned in the solution present in the acrylic microcell. After the tests, a size 08 K-file was used passively to verify the possibility of bypassing the fragment, which was also confirmed by radiographic analysis. Micro-CT analysis of the teeth was used before and after fragment dissolution to evaluate the volume, length and porosity of the fragments. The D'Agostino-Pearson normality test was used to verify the distribution of the data. A paired t-test (P < 0.05) was used to compare the volume, length and porosity of the fragments before and after the dissolution tests. RESULTS After dissolution, all fragments could be bypassed with a size 08 K-file in both simulated canals and in extracted teeth. The dissolution process did not result in significant reduction of neither the fragment length nor the fragment porosity. However, it resulted in a significant reduction of fragment volume (paired t-test, P < 0.05). CONCLUSION The electrochemical dissolution of fragments of NiTi files in root canals of extracted human maxillary molars using two electrodes, and the solution restricted to a small reservoir coupled to the pulp chamber resulted in a significant reduction of fragment volume. The re-establishment of the root canal path with the passive insertion of size 08 K-files was possible in all samples after the tests, both in simulated canals and in extracted teeth.

中文翻译：

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使用少量电解液储存镍钛仪器碎片在提取的人类上颌磨牙的根管中的电化学溶解。

目的使用两个电极并将溶液限制在与牙髓腔相连的小储液罐中，以评估破碎的NiTi器械碎片在已提取的人类上颌磨牙的根管中电化学溶解的可行性。最初的假设是，该方法可以减少碎片的体积，并可以在模拟的运河和提取的人类上颌磨牙中重建大小为08 K的根管路径。方法学F1 ProTaper器械的碎片在模拟的根管和提取的上颌磨牙的口腔颊根管中极化，采用的是一种新方法，其溶液仅限于与每个树脂块或浆腔相连的小型丙烯酸微孔。使用了两个电极，其中一个保持与管内片段接触，另一个保持在丙烯酸微池中存在的溶液中。测试后，被动地使用大小为08 K的文件来验证绕过碎片的可能性，这也通过射线照相分析得到了证实。在碎片溶解之前和之后使用牙齿的Micro-CT分析来评估碎片的体积，长度和孔隙率。使用D'Agostino-Pearson正态性检验来验证数据的分布。配对t检验（P <0.05）用于比较溶出度测试前后的碎片体积，长度和孔隙率。结果溶解后，所有碎片均可以在模拟管和拔出的牙齿中绕过08 K尺寸的锉刀。溶解过程不会导致碎片长度或碎片孔隙率的显着降低。但是，它导致片段体积显着减少（配对t检验，P <0.05）。结论使用两个电极将镍钛锉碎片的电化学溶解在提取的人类上颌磨牙的根管中，溶液限制在与牙髓腔相连的小储液罐中，导致碎片体积显着减少。在测试后的所有样本中，无论是在模拟的根管还是在拔出的牙齿中，都可以通过被动插入08 K锉刀来重建根管路径。结论使用两个电极将镍钛锉碎片的电化学溶解在提取的人类上颌磨牙的根管中，溶液限制在与牙髓腔相连的小储液罐中，导致碎片体积显着减少。在测试后的所有样本中，无论是在模拟的根管还是在拔出的牙齿中，都可以通过被动插入08 K锉刀来重建根管路径。结论使用两个电极将镍钛锉碎片的电化学溶解在提取的人类上颌磨牙的根管中，溶液限制在与牙髓腔相连的小储液罐中，导致碎片体积显着减少。在测试后的所有样本中，无论是在模拟的根管还是在拔出的牙齿中，都可以通过被动插入08 K锉刀来重建根管路径。