Fazilat Farzad, Ghoreishian Mahdi, Fekrazad Reza, Kalhori Katayoun A M, Khalili Sara Dehghan, Pinheiro Antonio Luiz Barbosa
1 Oral and Maxillofacial Surgery Department, Dental Faculty, AJA University of Medical Sciences , Tehran, Iran .
Photomed Laser Surg. 2014 Jun;32(6):315-21. doi: 10.1089/pho.2013.3559.
Therapeutic lasers have been shown to influence bone physiology and repair. The aim of the present investigation was to evaluate the use of a GaAlAs (λ:810 nm) laser in distraction osteogenesis.
To reduce problems associated with distraction osteogenesis and shorten the time required for treatment, it is desirable to accelerate the process of bone formation.
Eighteen male rabbits underwent corticotomy of mandibular body, and customized distraction devices were inserted. After a 5-day latency period, the mandibles were lengthened by 0.5 mm/day for 10 days. The rabbits were divided into two groups. A GaAlAs (λ: 810 nm) laser beam with the parameters power (P), 200 mW; energy density (ED), 3 J/cm(2); time (T), 7.5 sec; power density (PD) 400 mW/cm(2); energy (E) 1.5 J and spot diameter, 0.8 mm was directed medially and laterally in the study group; the control group received no laser treatment. The exposure continued with six more doses every other day. Three rabbits from each of the two groups were euthanized on the 10th, 20th, and 40th days post-distraction (consolidation) period.
Both light microscopy and scanning electron microscopic (SEM) analysis showed significant improvement in new bone formation in the study group at the 10th and 20th days compared with the control group, but the difference was more prominent on the 10th day. By the 40th day, there were no significant differences between the two groups.
This study shows that a low-level GaAlAs (λ:810 nm; P, 200 mW) laser hastens new bone formation only in the early stages of the consolidation period in distraction osteogenesis, and has no significant effect in later stages.
已证明治疗性激光会影响骨生理和修复。本研究的目的是评估GaAlAs（波长：810 nm）激光在牵张成骨中的应用。
为减少与牵张成骨相关的问题并缩短所需治疗时间，加速骨形成过程是很有必要的。
18只雄性兔子接受下颌体皮质切开术，并植入定制的牵张装置。经过5天的潜伏期后，下颌骨以每天0.5 mm的速度延长10天。兔子被分为两组。研究组用参数为功率（P）200 mW、能量密度（ED）3 J/cm²、时间（T）7.5秒、功率密度（PD）400 mW/cm²、能量（E）1.5 J且光斑直径为0.8 mm的GaAlAs（波长：810 nm）激光束向内侧和外侧照射；对照组不接受激光治疗。每隔一天继续进行6次照射。在牵张（巩固）期后的第10天、第20天和第40天，每组处死3只兔子。
光学显微镜和扫描电子显微镜（SEM）分析均显示，与对照组相比，研究组在第10天和第20天新骨形成有显著改善，但在第10天差异更明显。到第40天，两组之间无显著差异。
本研究表明，低强度GaAlAs（波长：810 nm；P，200 mW）激光仅在牵张成骨巩固期的早期阶段能加速新骨形成，而在后期无显著作用。
