Effect of Nd:YAG laser on bone formation in rat tibia defects: three-dimensional micro-computed tomography image analysis.

Nd:YAG laser is in common clinical use for the treatment of tissue incision, transpiration, and haemostasis in soft tissues. However, few studies have reported the effects of low-level laser therapy (LLLT) from Nd:YAG laser on bone healing. The aim of this study was to perform three-dimensional (3D) morphological evaluation of the photobiomodulation of Nd:YAG laser in bone defects in rat tibiae using micro-computed tomography CT (micro-CT) imaging. A bone defect was created in each tibia of 30 rats. The right side was treated with LLLT from Nd:YAG laser (LT group) daily until sacrifice and the left tibiae served as controls (control group). All tibiae underwent micro-CT imaging at 7, 14, and 21 days after the operation. Three-dimensional image analysis of bone volume (BV) and bone surface area (BS) of new bone formation in the defects was performed and histologic analysis was conducted for all tibiae. Tibial BV and BS values were highest in both groups at 7 days after the operation and decreased at 14 days after operation. BV and BS values were both significantly higher in the LT group than in the control group at 7 and 14 days. There was no significant difference between the groups for either metric at 21 days. The present findings demonstrate that Nd:YAG laser simulates bone formation during the early healing period.

Effect of Low-intensity Pulsed Ultrasound on Healing of Bone Defects in Rat Tibia as Measured by Reconstructed Three-dimensional Analysis of Micro CT Images.

BACKGROUND/AIM: The aim of this study was to evaluate the effect of low-intensity pulsed ultrasound (LIPUS) on bone metabolism during the healing period in rat tibiae bone defects using micro-computed tomography (micro CT) imaging for three-dimensional morphological evaluation. MATERIALS AND METHODS: The right tibia received ultrasound exposure (US group) every day, whereas the opposite side served as a control (Control group). At 1, 2, and 3 weeks after the operation, micro CT was performed, and the volume and surface area of new bone formation in the bone defects was evaluated three-dimensionally. RESULTS: Bone volume (BV) and bone surface (BS) in the tibiae of both the US and Control groups demonstrated the highest values 1 week after the operation, with no significant differences between the groups. At 2 weeks after the operation, the BV and BS values in both groups had decreased, but the decrease was smaller in the US group than the Control group. At 3 weeks after the operation, the BV and BS values in the Control group were significantly lower than those in the US group. CONCLUSION: LIPUS stimulation can prevent bone loss during the healing of bone defects.