Effects of Diode Laser Irradiation on Bone Formation in the Tibiae of Estrogen-deficient Rats

Background/Aim: The aim of this study was to examine the effects of diode laser irradiation (910 nm) on bone formation in tibiae with bone defects in estrogen-deficient rats. Micro-computed tomography (micro-CT) was performed for 3-dimensional (3D) morphological evaluation of newly formed bone tissues. Materials and Methods: Rats underwent sham operation (Sham) or ovariectomy (OVX), and bone defects were created in the tibiae, which were then subjected to diode laser irradiation for seven days in the laser groups (Sham-laser or OVX-laser groups). Tibiae with bone defects from Sham or OVX groups were irradiated with a guide light instead of a laser, serving as control groups (Sham-Cont or OVX-Cont groups). The tibiae were exposed to laser irradiation every day over a period of seven days. After irradiation, the tibiae underwent micro-CT, and then 3D reconstruction was performed for analysis of new bone formation. Results: Estrogen deficiency induced osteoporosis in the tibiae of OVX rats. Laser irradiation induced greater new bone formation in the region of bone defects in both Sham- and OVX-laser groups compared to the Sham- and OVX- Cont groups, respectively. No significant difference in the volume of new bone formation was seen between Sham- and OVX-laser groups. Conclusion: Laser irradiation could induce new bone formation in the region of bone defects in both Sham and OVX rats. This suggests that laser irradiation has potential for bone regeneration therapy in cases of postmenopausal osteoporosis.