根管遗漏往往会引起残髓炎或根尖周病变。上颌第一磨牙近中颊根第二根管(second mesio-buccal canal,MB2)因其细小、弯曲、根管口较为隐蔽,在临床上常造成根管遗漏,继而导致根管治疗的失败。因此,如何定位和疏通MB2是临床治疗中的难点。现报道1例上颌第一磨牙MB2遗漏的再治疗,以期为临床治疗提供参考。1病例资料 Root canal leakage often leads to residual myelitis or periapical lesions. The second mesio-buccal canal (MB2) of the maxillary first molars is often subtle in clinical practice due to its small size and curvature. The root canal mouth is often hidden, leading to the failure of root canal therapy. Therefore, how to locate and clear MB2 is a difficult point in clinical treatment. We report a case of maxillary first molar MB2 missing re-treatment, with a view to providing a reference for clinical treatment. 1 case information