本文报告1例成功处理涉及器械分离、纤维桩取出、医源性根管穿孔及慢性根尖周炎等复杂情况的左上第二磨牙(27)显微根管再治疗病例。患者主诉左上后牙反复牙龈肿包半年, 该患牙曾于两年前行根管治疗及桩核冠修复。临床检查发现颊侧根尖区牙龈存在窦道; 锥形束CT(cone-beam CT, CBCT)检查发现近中颊根根尖区存在一长度约5 mm的金属分离器械, 腭根内有一纤维桩延伸至根管中段, 近中颊根、远中颊根和腭根根管内充填物均存在明显欠填, 且根尖周均可见低密度影像。诊断为27慢性根尖周炎(牙髓治疗后), 治疗计划为27显微根管再治疗。橡皮障隔离, 在牙科显微镜下, 利用超声技术取出了腭根内的纤维桩及近中颊根分离器械的上段(2.5 mm)。再次探查根管时发现近中颊根根管冠1/3处的医源性穿孔。鉴于分离器械下段位置深在, 较难取出, 评估风险和获益后, 治疗策略调整为旁路通过, 最终成功绕过器械并疏通根管至工作长度。经过彻底的化学-机械预备后, 采用热牙胶垂直加压技术进行三维充填, 并使用iRoot BP生物陶瓷材料对穿孔部位进行严密修补, 完成患牙全冠修复。术后10个月随访时, 患者无临床症状, 影像学检查示根尖周病变愈合良好。本病例表明, 综合运用CBCT、牙科显微镜、超声技术和生物陶瓷材料, 并采取保守而灵活的治疗策略, 能够提高多重并发症根管再治疗病例的成功率。

This case report describes the micro-endodontic retreatment and comprehensive management of a complex left maxillary second molar presenting with multiple complications. The patient, a 41-year-old female, presented with recurrent gingival swelling associated with the tooth for more than six months. The tooth had a history of root canal treatment, fiber post placement, and full crown restoration two years earlier. Cone-beam CT (CBCT) revealed a separated metallic instrument approximately 5 mm in length in the apical region of the mesiobuccal root, a fiber post in the palatal root, underfilled root canal obturation, and periapical radiolucency involving the mesiobuccal, distobuccal and palatal roots. A diagnosis of chronic periapical periodontitis (post-endodontic treatment) was established. The primary challenges included the limited access to the left maxillary second molar, the deeply embedded apical instrument segment, and the high risk for complications, such as root fracture or secondary perforation during retrieval attempts. The treatment strategy involved removal of the separated instrument and retreatment under a dental operating microscope. With ultrasonic assistance, the palatal fiber post and the coronal segment (2.5 mm) of the separated instrument from the mesiobuccal canal were successfully removed. An iatrogenic lateral perforation occurred in the mesiobuccal canal near the furcation area during the instrument retrieval procedure. Given the depth and high risk of further damage from retrieving the remaining apical segment (2 mm), a conservative and flexible approach was adopted using the bypass technique. After successful bypassing, thorough chemo-mechanical debridement was performed, followed by obturation using the warm vertical compaction technique. The iatrogenic perforation on the distal wall of the mesiobuccal canal was immediately repaired with a bioceramic material (iRoot BP) for its superior sealing and bioactivity. The tooth was then restored with a full crown. A 10-month follow-up showed that the patient was asymptomatic with complete fistula healing and radiographic examination revealed favorable healing of the periapical lesion. This case demonstrates that, in complex root canal retreatment cases involving retained instruments and iatrogenic perforations, the integration of advanced diagnostic tools (e. g. CBCT), microsurgical techniques (e. g. microscope and ultrasound), and modern restorative materials (e. g. bioceramics), along with a dynamic strategy combining instrument retrieval and bypassing, is essential for achieving predictable long-term success.

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作者贡献声明  臧海玲：接诊患者，完成病例的诊断治疗及资料的收集整理，撰写，修改论文；梁宇红：总体把关，对论文的撰写修改作出指导并进行审定。所有作者均参与论文修改，并对最终文稿进行审读和确认。