Abstract
Background and Objectives
Bone remodeling is characterized as a cyclic and lengthy process. It is currently accepted that not only this dynamics is triggered by a biological process, but also biochemical, electrical, and mechanical stimuli are key factors for the maintenance of bone tissue. The hypothesis that lowβlevel laser therapy (LLLT) may favor bone repair has been suggested. The purpose of this study was to evaluate the bone repair in defects created in rat lower jaws after stimulation with infrared LLLT directly on the injured tissue.
Study Design/Materials and Methods
Bone defects were prepared on the mandibles of 30 Holtzman rats allocated in two groups (nβ=β15), which were divided in three evaluation period (15, 45, and 60 days), with five animals each. control groupβno treatment of the defect; laser groupβsingle laser irradiation with a GaAlAs semiconductor diode laser device (Ξ»β=β780 nm; Pβ=β35 mW; tβ=β40 s; Ξβ=β1.0 mm; Dβ=β178 J/cm^2^; Eβ=β1.4 J) directly on the defect area. The rats were sacrificed at the preβestablished periods and the mandibles were removed and processed for staining with hematoxylin and eosin, Masson's Trichrome and picrosirius techniques.
Results
The histological results showed bone formation in both groups. However, the laser group exhibited an advanced tissue response compared to the control group, abbreviating the initial inflammatory reaction and promoting rapid new bone matrix formation at 15 and 45 days (P<0.05). On the other hand, there were no significant differences between the groups at 60 days.
Conclusion
The use of infrared LLLT directly to the injured tissue showed a biostimulating effect on bone remodeling by stimulating the modulation of the initial inflammatory response and anticipating the resolution to normal conditions at the earlier periods. However, there were no differences between the groups at 60 days. Lasers Surg. Med. 39:788β796, 2007. Β© 2007 WileyβLiss, Inc.