Abstract: Objective　To evaluate the effect of low-level laser therapy on pain associated with orthodontic alignment stage or space-closing stage. Methods　From July 2017 to February 2018，19 patients in the initial stage of orthodontic treatment and 17 patients in the final stage of closing the spaces in the arch were recruited in the experiment in the Department of Stomatology，Peking Union Medical Hospital. The experiment side was irradiated with a diode laser for 40 sec per tooth both on buccal and palatal side（810 nm，0.5 W，4 W/cm2），while the control side with indication light. A numeric rating scale was used to access the spontaneous and chewing pain in the following one week. The Mann-whitney test was used to compare the scores. Results　Low-level diode laser therapy significantly reduced both the spontaneous pain and chewing pain in the initial stage of orthodontic treatment（P < 0.05），while the effect was not distinct in orthodontic final stage（P > 0.05）. Conclusion　Low-level diode laser irradiation can significantly reduce the pain in the leveling and alignment stage of orthodontic treatment.

Key words: low-level diode laser therapy, orthodontic, analgesia

摘要： 目的　研究低能量半导体激光对佩戴固定矫治器正畸患者在初始排齐和牙弓完全整平后滑动法关闭拔牙间隙2个阶段加力后牙齿疼痛的缓解作用。方法　选取2017年7月至2018年2月于北京协和医院口腔科就诊处于正畸初始阶段的患者19例，处于滑动法关闭拔牙间隙阶段的患者17例。采用单盲、自身牙弓左右侧对照的研究方法，正畸加力后使用低能量半导体激光（810 nm、0.5 W、4 W/cm2）分别照射研究侧牙弓颊侧、腭侧牙周膜区域（连续波模式、40 s/颗），对照侧相应区域采用指示光进行照射。加力后1周内，患者每日填写疼痛数字评价量表，采用Mann-Whitney检验比较研究侧和对照侧的疼痛差异。结果　在正畸初始阶段应用低能量半导体激光照射，在加力后前3 d均可显著减轻咬合痛，在加力后第1天可显著减轻自发痛（P < 0.05）；而在滑动法关闭拔牙间隙阶段，低能量半导体激光缓解这2种疼痛的作用在研究侧和对照侧间无明显差异（P > 0.05）。结论　低能量半导体激光可明显缓解临床患者在正畸初始阶段的疼痛。

关键词: 低能量半导体激光, 正畸, 疼痛