Effect of Low Level Laser Therapy on Bone Histomorphometry in Rats

The aim of this study was to assess the histological effect of Low Level Laser Therapy (LLLT) (904 nm) on the repair of standardized bone defects on the femur of rats. Sixty male wistar rats were assigned into two equal groups. Group (A: laser group) and group (B: control group). A surgical fracture was done in middle third of femur of all rats. In group (A) a continuous wave 904 nm infrared laser was applied at dose 4 j/cm(2) at fracture site immediately post operative for 7 sessions, each session was 5 minutes. The animals were killed by over dose of general anesthesia on the 15th, 30th and 45th days after surgery, The specimens were processed and stained with Hematoxylin-eosin (H/E), special stain Masion trichrome and analyzed by light microscopy. The descriptive analysis of histological imaging showed greater degree of new bone formation, osteoblastic surface and collagen fiber in the irradiated group when compared with the control group. Based on the obtained results, this study concluded that LLLT was efficient in promoting bone healing, and increasing new bone formation in the process of surgically fractured femur in animal study.