In vivo bone regenerative effect of low-intensity pulsed ultrasound in rat calvarial defects

ObjectivesLow-intensity pulsed ultrasound (LIPUS) is a biophysical intervention in a bone repair process. However, neither the healing events of the flat bones of the skull using LIPUS nor the optimal stimulation settings are fully understood. The aim of this study was to evaluate the bone regenerative effect of LIPUS in rat calvarial flat bone defects by using in vivo microfocus computerized tomography (micro-CT).Study designThe calvarium was exposed, and noncritical-sized 2.7-mm defects were prepared. LIPUS (1.6 MHz, repeating 1.0-kHz pulsation, and 30-mW/cm2 intensity) was applied for 20 minutes daily. Bone regeneration was evaluated by image analysis using micro-CT and histologic examination.ResultsWithin 2 weeks, LIPUS-treated rats demonstrated 7.0% reossification of the original surgical defect, whereas control rats demonstrated 3.6%. At 3 and 4 weeks, a significant difference in the reossification ratio was observed (12.0% vs. 5.8% and 18.1% vs. 9.8%, respectively; P < .05).ConclusionsLIPUS accelerated bone regeneration of noncritical rat calvarial defects as confirmed by micro-CT.