Bone tissue microscopic findings related to the use of diode laser (830ηm) in ovine mandible submitted to distraction osteogenesis

Purpose: To analyze the microscopic characteristics of the effect of Gallium-Aluminum Arsenid diode laser (GaAlAs-830 eta m) applied during the activation and consolidation period to ovine mandibles submitted to distraction osteogenesis. Methods: Eighteen sheep underwent surgery in order to have bone distractors implanted in the left side of the jaw area. They were divided into three groups: 1 - Control; 2 - Laser irradiation during the activation period; 3 - Laser irradiation during the fixation period. The irradiation was carried out in five sessions, on every other day, with 4,0J/cm(2) doses applied to four pre-established areas, totaling 16J per session. After four days of latency under post-operative care, ten days of distractor activation (at 1 mm/day) and twenty-one days of fixation the animals were sacrificed and the devices removed for microscopic analysis. Results: The groups that received laser irradiation (GaAlAs) presented a greater amount of mineralized bone trabeculae when compared to the Control Group. Despite that, cartilaginous tissues were also found in Group 2. Conclusion: The laser has been more favorable when used in the consolidation period, after bone elongation. Key words: Lasers. Bone lengthening. Wound healing. Sheep.