Thesis (Ph.D.) - Cairo University - National Institute of Laser Enhanced Science - Department of Laser Applications on in Medical and Biological

Objective: This study was conducted to determine the effect of low level laser therapy (LLLT) on bone repair in rats. Materials and methods: Seventy two rats were assigned randomly into three groups, group (A) consisted of twenty four rats whose bone fracture didn{u2019}t receive laser therapy, group (B) consisted of twenty four rats whose bone fracture received He-Ne laser (632.8 nm) and group (C) consisted of twenty four rats whose bone fracture received Ga-As laser (905 nm). Each group was subdivided into three subgroups according to their sacrificing day on 15th, 30th and 45th post-operative days. Assessment of bone fracture healing was done through radiological analysis and histopathological analysis. Results: The results of this study revealed that group (C) showed more complete bone regeneration on 15th and 30th post-operative days when compared with groups (A&B) according to the radiological findings. According to the histopathological analysis, on 15th and 30th postoperative days, there was no statistically significant difference between groups (A&B) (p > 0.05) in newly formed blood vessels, fibroblasts, osteiod and bone formation scores. While, there was a significant difference between groups (A&C) and (B&C) (p value < 0.05) in favor of group (C). Conclusion: Ga-As laser showed a bio-stimulating effect on the rate of bone repair by stimulating the modulation of the initial inflammatory response and anticipating the resolution to normal condition at the earlier periods. Both He-Ne and Ga-As lasers were not different from the control group on 45th postoperative day

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