Purpose: The stimulating effect of low-power laser on the process of wound healing is characterized by the proliferation of fibroblasts, faster collagen production, and enhanced enzyme activity. The aim of this study was to experimentally evaluate the histological effect of low-power laser on healing of bone defects. Materials and Methods: Eight albino Wistar rats were used. Round defects (3 mm wide, 2 mm deep) were made in each rat on both femurs, right (experimental side) and left (control side). The experimental sides were treated daily with a 637-nm GaAlAs low-power laser, at a power output of 50 mW, using 4 J/cm2 per defect for 7 days; the control sides were left to heal spontaneously. The effects of laser irradiation were evaluated 2 and 3 weeks postoperatively. Results: Histological analysis showed strong osteoblastic activity in bone defects of the experimental side 2 weeks after surgery. At the same time, newly formed bone growths were found at the periphery of bone defects, and fibroblastic tissue with no signs of new bone formation was noticed in the central area of the bone defects on the control side. Three weeks after surgery, experimental bone defects were completely filled with spongious lamellar bone; in the same period, control bone defects were characterized by mature lamellar bone at the periphery, and immature bone in the central areas. Conclusion: These results show that the use of low-power laser can have a significant influence on the speed of healing bone defects.
Keywords: low-power laser, GaAlAs laser, bone defect, bone healing, osteoblastic activity, experimental study