Wu G, Chen L, Zhu G, et al.
BACKGROUND: To investigate whether low-intensity ultrasound accelerates healing in bone tissues close to dental implants with osteoradionecrosis (ORN) of the mandible and is suitable for development as a therapy in patients with dental implants receiving radiotherapy. MATERIALS AND METHODS: Dog models of radiative bone injury surrounding dental implants in both sides of mandible were established by four treatment methods of radiotherapy, each 15Gy. After radiative treatment, antibiotics were administered and the left injury was treated with ultrasound and the right with debridement. Measures for evaluation included spiral computed tomography (SCT), Micro-CT, microvessel density, and pull-out experiment, and data were collected and analyzed. RESULTS: After 4months of radiotherapy, both sides of mandible displayed preclinic symptom of radiative osteonecrosis. Microvessel density of the side treated by ultrasound was 6.2152+/-0.6508 and that of the debridement side was 3.8490+/-0.8954 (P<0.05). Micro-CT results showed that bone volume fraction of trabecula, thickness of trabecula, trabecula spacing, ratio of bone surface area to bone volume, and trabecula number of the ultrasound-treated mandible were 0.3605+/-0.0337, 0.0287+/-0.0045, 0.0369+/-0.0073, 71.6124+/-14.1649, and 7.2915+/-1.4937, whereas those of the debridement side were 0.1779+/-0.0178, 0.0151+/-0.0021, 0.6623+/-0.1125, 33.2686+/-5.949, and 5.0689+/-0.5028, respectively; statistical significance was observed (P<0.05). Pull-out experiment suggested that pull-out strength of the ultrasound-treated side was 0.5793+/-0.1066 whereas that of the debridement side was 0.2980+/-0.0243, representing a statistical significance (P<0.05). CONCLUSIONS: Low-intensity ultrasound can accelerate the healing of bone tissues surrounding dental implants in osteoradionecrosis of the mandible animals.