Effect of low intensity pulsed ultrasound on osteoclast differentiation

ABSTRACT Purpose For many years, people have attempted to identify ways of efficiently moving teeth in orthodontic therapy to reduce harmful effects. In this study, we investigate whether the non-surgical method of low-intensity pulsed ultrasound (LIPUS) irradiation affects osteoclast differentiation in vitro. Materials and Methods RAW264 cells were stimulated with RANKL and U0126, and LIPUS irradiation was performed using different ultrasonic outputs, irradiation times, and number of irradiations. Assessments used TRAP staining, TRAP quantitative assays, and western blot analysis. Results LIPUS irradiation significantly increased osteoclast differentiation rates of RAW264 cells. The rates were significantly higher in the three-time irradiation group compared with the single irradiation group. However, significant differences were not observed between the ultrasonic output. TRAP quantitative assay results showed significantly increased osteoclast differentiation rates with increased irradiation time, however, only in the single irradiation group. Conclusion These results suggest that an increased number of LIPUS irradiations may improve its effectiveness in orthodontic therapy.