a Graduate student, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
Angle Orthod. 2013 Nov;83(6):1015-21. doi: 10.2319/100812-789.1. Epub 2013 May 14.
To analyze the effect of low-level laser on bone remodeling during induced tooth movement in rats.
A diode laser (808 nm, 100 mW, 54 J on an area of 0.0028 cm(2)) was used. The application was continuous, punctual, and with contact. Forty-two 70-day-old Wistar rats had the maxillary left first molar moved using a force level of 25 g. In two experimental subgroups the movement was performed over 7 days and in three subgroups the movement occurred over 14 days. In the 7-day movement subgroups, one subgroup received laser irradiation on day 1 only; the other subgroup received laser irradiation on days 1, 3, and 5. In the 14-day movement subgroups, one subgroup received laser irradiation on day 1 only; the second on days 1, 3, and 5; and the third on days 1, 3, 5, 7, 9, 11, and 13. The control group was also divided into two subgroups, and movement occurred over two different periods of treatment (7 days and 14 days) without laser application; these were used as controls for the respective experimental subgroups. Inter-subgroup comparison was performed with Kruskal-Wallis, followed by Mann-Whitney and analysis of variance, followed by Tukey tests within the 7- and 14-day subgroups.
The subgroup with three laser applications showed significantly greater osteoclastic activity and bone resorption than the other subgroups in the 7-day movement subgroups.
Low-level laser application significantly increased the osteoclastic but not the osteoblastic activity during the initial phases of tooth movement. In addition, the osteoclastic activity was dose-dependent.
分析低水平激光在诱导大鼠牙齿移动过程中对骨重塑的影响。
使用二极管激光（808nm，100mW，54J 作用于 0.0028cm² 的面积）。应用方式为连续、点状、接触式。42 只 70 天大的 Wistar 大鼠通过 25g 的力水平使左侧上颌第一磨牙移动。在两个实验组中，移动时间为 7 天，在三个实验组中，移动时间为 14 天。在 7 天的移动实验组中，一个实验组仅在第 1 天接受激光照射；另一个实验组在第 1、3 和 5 天接受激光照射。在 14 天的移动实验组中，一个实验组仅在第 1 天接受激光照射；第二个实验组在第 1、3 和 5 天接受激光照射；第三个实验组在第 1、3、5、7、9、11 和 13 天接受激光照射。对照组也分为两个亚组，分别在不同的治疗期（7 天和 14 天）进行移动，没有激光应用；这些作为各自实验组的对照。采用 Kruskal-Wallis 进行组间比较，然后进行 Mann-Whitney 和方差分析，再在 7 天和 14 天亚组内进行 Tukey 检验。
在 7 天移动实验组中，接受三次激光应用的实验组的破骨细胞活性和骨吸收明显高于其他实验组。
低水平激光应用在牙齿移动的初始阶段显著增加了破骨细胞活性，但对成骨细胞活性没有影响。此外，破骨细胞活性呈剂量依赖性。
