Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||TOHOKU UNIVERSITY |
CHIBA Mirei (2001-2003) TOHOKU UNIVERSITY, GRADUATE SCHOOL OF DENTISTRY, RESEARCH ASSOCIATE, 大学院・歯学研究科, 助手 (10236820)
清水 義信 (2000) 東北大学, 大学院・歯学研究科, 助教授 (20005078)
KAGAYAMA Manabu TOHOKU UNIVERSITY, GRADUATE SCHOOL OF DENTISTRY, PROFESSOR, 大学院・歯学研究科, 教授 (60004610)
SHIMIZU Yoshiyuki TOHOKU UNIVERSITY, HOSPITAL, LECTURER, 医学部附属病院, 講師 (20187470)
SHIMIZU Yoshinobu TOHOKU UNIVERSITY, GRADUATE SCHOOL OF DENTISTRY, ASSOCIATE PROFESSOR, 大学院・歯学研究科, 助教授 (20005078)
MITANI Hideo TOHOKU UNIVERSITY, GRADUATE SCHOOL OF DENTISTRY, PROFESSOR, 大学院・歯学研究科, 教授 (50014220)
三木 美麗 東北大学, 大学院・歯学研究科, 助手 (10236820)
|Project Period (FY)
2000 – 2003
Completed (Fiscal Year 2003)
|Budget Amount *help
¥12,600,000 (Direct Cost: ¥12,600,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2000: ¥6,800,000 (Direct Cost: ¥6,800,000)
|Keywords||Resonance Vibration / Orthodontic Tooth Movement / Mechanical Stress / Periodontal tissue / RANKL / OPG / Osteoclasts / Root Resorption / 振動刺激 / 共振周波数 / 歯周組織改造機構 / 歯科矯正学的歯の移動 / 共振点 / 歯周組織改造機 / プロスタグランジン / 歯周組織再生 / 共焦点 / プロタグランジン|
Accelerating the speed of orthodontic tooth movement should shorten the treatment period, which is one of the negative aspects of orthodontic treatment. This study evaluated the effects of mechanical stimulation using resonance vibration on tooth movement and revealed the cellular and molecular mechanism of the periodontal ligament responses.
The upper first molars of 6-week-old male Wistar rats were moved to the buccal side using an expansive spring for 21 days (n=6,control group) and the amount of tooth movement was measured. Additional vibrational stimulation (60 Hz,1.0 m/s^2) was applied to rat first molars using a loading vibration system for 8 minutes on days 0,7,and 14 during orthodontic tooth movement (n=6,experimental group). The animals were sacrificed under anesthesia and the upper jaw dissected. The specimens were fixed, decalcified, and embedded in paraffin. Sections were used for immunohistochemical analysis of receptor activator of NF kappa B ligand (RANKL) expression. The number of osteoclasts in the alveolar bone was counted using TRAP staining and the amount of root resorption was measured in sections stained with H-E.
The average resonance frequency of the upper first molar was 61.02±8.38 Hz. Tooth movement in the experimental group was significantly greater than in the control group (p<0.05). Enhanced RANKL expression was observed at fibroblasts and osteoclasts in the periodontal ligament of the experimental group on day 3. The number of osteoclasts in the experimental group was significantly increased over the control group on day 8 (p<0.05). Histologically, there were no pathological findings in either group or significant differences in the amount of root resorption between the two groups.
The application of resonance vibration might accelerate orthodontic tooth movement via enhanced RANKL expression in the periodontal ligament without additional damage to periodontal tissues, such as root resorption.