بررسي بافت شناسي تاثير ليزر كمتوان GaAs بر سرعت و كيفيت تشكيل استخوان در Distraction Osteogensis در خرگوش

Histological study of effect of low level laser GaAs on rate and quality of bone formation in distraction osteogenesis in rabbit

Introduction: Although distraction osteogenesis is a surprising modality in treatment of many of deformities in craniofacial region, but often tolerance of distractor devices is hard and problematic for many of patients. If low level lasers can increase rate of ossification, cause shortening of treatment duration, and cause lessening of problems of patients. Therefore, purpose of this study was determination of effectiveness of low level laser in acceleration of new bone formation and consequently shortening of treatment period and decrease ofproblems of distractor device. Materials and Method: In this study, after corticotomy, distractor devices were placed in mandibular body of 18 white zelanian rabbits and after 5 days, were activated at a rate of lmm/day for 10 days. 9 rabbits were exposed to 7 doses of GaAs laser with power of200 /uw every other day and other 9 rabbits received no laser. Then, the rabbits were periodically sacrificed in the 10th, 20th and 40th days of consolidation period and obtained samples were studied by scanning electron microscopy and light microscopy and then analyzed by Mann-Whitney method (D= 0.05). Results: In SEM and histological examinations, the amount and orientation of fibroblasts and fibrous tissue in the 10th day was greater in laser group than in control group. In the 20th day, in addition to fibrous tissue, the amount of woven bone was greater in laser group than that in control group but the degree of their difference wasnʹt significant and really was smaller as compared with the 10th day. In the 40th days in each of two groups of laser and control, woven and lamellar bone were seen but no significant difference of new bone formation was found in the laser group as compared with control group. It appears that laser radiation in initial stages of distraction is more effective than end stages.