目的探讨显微超声技术在在治疗上颌第一恒磨牙近颊根管的应用。方法以112颗上颌第一恒磨牙为研究对象,开髓后探查近颊第二根管(second mesiobuccal root canal,MB2),未能发现MB2者在牙科手术显微镜下(dental operating microscope,DOM)采用超声技术探查MB2根管口。结果上颌第一恒磨牙近颊第二根管肉眼下探查发现率为32.1%,使用显微镜后MB2的发现率为75.9%。结论显微超声技术有助于发现较隐匿的MB2根管口,对于完善根管治疗具有较大临床意义。 Objective To investigate the application of micro-ultrasound in the treatment of the maxillary first molar root canal. Methods One hundred and twelve maxillary first permanent molars were selected as the object of study. Second mesiobuccal root canal (MB2) was opened after open pulp, and those who failed to find MB2 were used in dental operating microscope (DOM) Ultrasound exploration of the root canal of MB2. Results The detection rate of the second root canal of the maxillary first permanent molars was 32.1%. The detection rate of MB2 after using the microscope was 75.9%. Conclusion Micro-ultrasound technique can help to find the more hidden MB2 root canal, which has great clinical significance for the improvement of root canal therapy.