Effect of Low-Intensity Pulsed Ultrasound on Bone Formation During Mandible Distraction Osteogenesis in a Canine Model-A Preliminary Study

Purpose: To make a preliminary study of the effect of low-intensity pulsed ultrasound oil new bone formation during mandible distraction osteogenesis in dogs. Materials and Methods: Bilateral surgical cuts were made in mandibles of 7 dogs between the first and second premolar regions Anterior mandibles were lengthened by 20 mm at the rate of 1 mm/day twice a day During the distraction period 1 lateral distraction gap was irradiated by low-intensity pulsed ultrasound for 10 minutes twice a day and the other side was sham irradiated as control After distraction was completed, the dogs were sacrificed at 0, 1, 2, 4, 6, 8, and 12 weeks. Before sacrifice, dynamic bone imaging with technetium (99)m-methylene diphosphonate ((99)mTc-MDP) single-photon emission computed tomography was performed Mandible samples were harvested Then plain x-ray, dual-energy x-ray bone mineral density measurement. 3-dimensional computed tomography, and regular histologic examination were performed. Results: The (99)mTc-MDP bone imaging showed that uptake of (99)mTc-MDP in the experimental side was higher than in the control side it the early period of the consolidation side was mature sooner than that of the reversed. Plain x-my showed that new bone of the experimental side was mature sooner than that of the control side Bone mineral density ill the experimental side was higher than that of the control side Volume of new bone of the 2 sides had no significant difference Histologic examination showed that trabeculae Of the experimental side were more numerous and thicker than those of the control side at the early period of the consolidation time. Endochondral bone formation was observed ill the experimental side. Conclusion: Low-intensity pulsed ultrasound could accelerate bone formation during mandibular distinction osteogenesis and increase bone mineral density but hid no effect oil the volume of new bone (C) 2009 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 67.2431-24139, 2009