Abstract: First molar missing or extraction is common in orthodontic clinic，and the protraction of the second molar to close the space of the missing tooth is an important method to replace the missing tooth and to maintain the occlusal function. However，many factors，such as patients′ age，tooth tilt angle and periodontal condition，should be taken into consideration during the second molar protraction. Besides，doctors should try to avoid the risk of alveolar bone and root absorption. Due to the strong anchorage effect of second molar，more rigorous anchorage design and effective support are needed. This review summarizes the indications，protraction method and risks，aming to provide clinical reference for the orthodontic treatment for closing the space of first molar missing or extraction by second molar protraction.

Key words: molar protraction, first molar missing, mini-implant anchorage, orthodontic treatment, space closure

摘要： 第一磨牙缺失或拔除在正畸临床中较为常见，近中移动第二磨牙关闭缺牙间隙是替代第一磨牙并维持咬合功能的重要手段。但第二磨牙近中移动不仅需要考虑患者年龄、牙轴倾斜角度及牙体牙周条件等多方面因素，还要尽量避免牙槽骨及牙根吸收风险。另外，由于磨牙的支抗作用强，在近中移动过程中需要更加科学严谨的支抗设计及有效的辅助手段。因此，文章就第二磨牙近中移动的适应证、方法和风险等进行综述，以期为第二磨牙近中移动关闭第一磨牙缺失或拔除间隙的正畸治疗提供临床参考。

关键词: 磨牙近中移动, 第一磨牙缺失, 微种植体支抗, 正畸治疗, 间隙关闭