The Effects of Low-Intensity Pulsed Ultrasound on Osteo/Cementoclastogenesis Induced by Compression Force Application

  • PhD, DDS Toshihiro Inubushi, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • Emanuel Rego, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • Aki Kawazoe, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • PhD, DDS Kotaro Tanimoto, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • PhD, DDS Mutsumi Miyauchi, Department of Oral and Maxillofacial Pathobiology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • PhD, DDS Eiji Tanaka, Department of Orthodontics and Dentofacial Orthopedics, The University of Tokushima Graduate School of Oral Sciences, Japan
  • PhD, DDS Takashi Takata, Department of Oral and Maxillofacial Pathobiology, Hiroshima University Graduate School of Biomedical Sciences, Japan
  • PhD, DDS Kazuo Tanne, Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Japan

Introduction: Root resorption is an adverse outcome of orthodontic treatment. However, the biological mechanisms remain unclear. Furthermore, there have been no available approaches for the protection and repair of root resorption. The aim of this study was to evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on osteo/cementoclastogenesis induced by compression force application.
Materials and methods: Gene expression related to osteo/cementoclastic activity of mouse cementoblast cell line (OCCM-30) and mouse osteoblast cell line (MC3T3-E1) were compared. Then, the effects of LIPUS on osteo/cementoclastic related genes expression were evaluated. In addition, the effects of LIPUS were examined when compression force was applied to the cells lines.
Results: Compared to OCCM-30, MC3T3-1 constitutively expressed higher levels of RANKL and RANTES mRNAs. On the contrary, OPG mRNA expression was much higher in OCCM-30. Meanwhile, no significant differences were observed in the mRNA expressions of MCSF and MIP-2. LIPUS stimulation significantly increased the mRNA expression of RANKL in MC3T3-E1 at 4 (p<0.01) and 12 hours (p<0.05), although OPG mRNA expression was not affected by LIPUS. In contrast, the expression of RANKL and OPG mRNAs was significantly increased by LIPUS in OCCM-30 at 12 hours (p<0.01). Moreover, LIPUS application suppressed the up-regulation of RANKL mRNA induced by compression force in OCCM-30, although the same effects were observed in MC3T3-E1.
Conclusions: It is shown that LIPUS exposure significantly inhibited the cementoclastgenesis induced by compression force application, suggesting that LIPUS may be an effective therapeutic tool for the prevention of root resorption during tooth movement.