Low-power laser therapy for repairing acute and chronic-phase bone lesions

To evaluate the therapeutic activity of low-power laser (InGaAlP: 670 nm/30 mW), at doses of 90 J/cm2, on the process of acute and chronic-phase repair of bone lesions of Wistar rats. Sixty-three adult males were divided into nine groups subjected to bone injury, in order to form the following treatments: T1 (control); T2 (acute-phase); T3 (chronic-phase) which were subdivided into three subgroups (n = 7), analyzed on the 9th, 17th and 28th days post-surgery, after a period of daily treatment with laser. The animals with acute-phase treatment presented a more extensive endochondral ossification process. Laser-treated animals showed significant increases in serum alkaline phosphatase levels and had an effect on biomechanical property, resulting in a gradual increase in bone stiffness. Laser therapy aided the bone consolidation process and favored the physiopathologic mechanisms involved in bone tissue repair, and its effects were more prominent when treatment started during the acute phase of the injury.