Effects of low-intensity pulsed ultrasound on healing of mandibular fractures:: An experimental study in rabbits

Purpose: Pulsed ultrasonic waves have been shown to accelerate fracture healing of the long bones. The aim of this study was to evaluate the effects of low-intensity pulsed ultrasound (LIPU) on healing of mandibular fractures. Materials and Methods: Thirty skeletally mature mate New Zealand rabbits were used. Animals underwent unilateral mandibular osteotomy. The bone segments were repositioned and fixed with miniplates and miniscrews. Half of the animals received daily ultrasound treatment, 20 min/day, for 20 days. Ultrasound signals consisted of a 1.5-MHz pressure wave administered in pulses of 200 mu sec with an average temporal and spatial intensity of 30 mW/cm(2). Animals in the control group received sham application. All of the animals were killed on postoperative day 22. Three-point bending test, digital radiodensitometric analysis, and histologic and histomorphometric examinations were performed on the harvested hemimandibles. The data were statistically analyzed. Results: Biomechanical tests revealed significant improvement in the mechanical properties of the healing bone in the LIPU-treated group. This was supported by histologic and radiologic findings. Conclusions: Results of this study suggest that LIPU improves the bone healing of mandibular fractures in rabbits. (c) 2006 American Association of Oral and Maxillofacial Surgeons.