Shirazi Mohsen, Ahmad Akhoundi Mohammad Sadegh, Javadi Ehsan, Kamali Abbas, Motahhari Pouria, Rashidpour Mahsa, Chiniforush Nasim
Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Lasers Med Sci. 2015 Feb;30(2):713-8. doi: 10.1007/s10103-013-1407-1. Epub 2013 Aug 7.
Low-level laser has been indicated to have the capability to facilitate the differentiation of the osteoclastic and osteoblastic cells which are responsible for the bone remodeling process. The aim of this study was to evaluate the effects of InGaAlP laser with a wavelength of 660 nm on the rate of tooth movement and histological status. Thirty male Wistar rats of 7 weeks old were selected for this study. The rats were randomly divided into two groups of 15 each to form the experimental (laser-irradiated) and control (non-irradiated) groups. The control group received unilateral orthodontic appliance design (one quadrant), but the laser-irradiated group received split-mouth design, with orthodontic appliance on both sides and laser irradiation on one side only (group b) and on the contralateral side (group c). The orthodontic appliance consisted of a NiTi closed coil spring with a length of 5 mm which was ligated to maxillary molar and incisor. A total of 60 g of force was applied to the rat molar. The diode laser (660 nm) was irradiated with an output power of 25 mW in continuous mode for a total time of 5 min in the laser-irradiated group. After 14 days of orthodontic tooth movement, the amount of tooth movements was measured. In the laser-irradiated group, the amount of tooth movement was significantly greater than that of the non-irradiated group (2.3-fold), but there was no significant difference between the non-irradiated and indirectly irradiated groups. Histopathological studies revealed that the number of osteoclasts in the laser-irradiated group was significantly greater than that of the non-irradiated group (1.5-fold) while this number was almost the same in the non-irradiated and indirectly irradiated groups. The results suggested that low-level laser can accelerate the rate of bone remodeling. However, in order to utilize the low-level laser as an adjunct in orthodontic practice on patients, further research studies are needed for finding the appropriate dosage for the human tissues.
低强度激光已被证明有能力促进负责骨重塑过程的破骨细胞和成骨细胞的分化。本研究的目的是评估波长为660nm的铟镓铝磷激光对牙齿移动速率和组织学状态的影响。本研究选取了30只7周龄的雄性Wistar大鼠。将大鼠随机分为两组，每组15只，分别形成实验组（激光照射组）和对照组（未照射组）。对照组接受单侧正畸矫治器设计（一个象限），但激光照射组采用分口设计，两侧均佩戴正畸矫治器，仅一侧接受激光照射（b组），另一侧接受对侧照射（c组）。正畸矫治器由一个长度为5mm的镍钛闭合螺旋弹簧组成，该弹簧结扎在上颌磨牙和切牙上。对大鼠磨牙施加总共60g的力。激光照射组使用二极管激光（660nm），以25mW的输出功率连续模式照射，总照射时间为5分钟。正畸牙齿移动14天后，测量牙齿移动量。在激光照射组，牙齿移动量显著大于未照射组（2.3倍），但未照射组和间接照射组之间无显著差异。组织病理学研究表明，激光照射组的破骨细胞数量显著多于未照射组（1.5倍），而未照射组和间接照射组的破骨细胞数量几乎相同。结果表明，低强度激光可加速骨重塑速率。然而，为了将低强度激光作为正畸临床对患者的辅助手段，还需要进一步的研究来确定适合人体组织的剂量。
