| Project/Area Number |
07557282
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Tohoku University |
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Principal Investigator |
MITANI Hideo Tohoku University, School of Dentistry, Professor, 歯学部, 教授 (50014220)
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| Co-Investigator(Kenkyū-buntansha) |
IGARASHI Kaoru Tohoku University, School of Dentistry, Assistant Professor, 歯学部, 助手 (70202851)
SHIMIZU Yoshiyuki Tohoku University, Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (20187470)
SHIMIZU Yoshinobu Tohoku University, School of Dentistry, Associate Professor, 歯学部, 助教授 (20005078)
SHINODA Hisashi Tohoku University, School of Dentistry, Professor, 歯学部, 教授 (80014025)
KAGAYAMA Manabu Tohoku University, School of Dentistry, Professor, 歯学部, 教授 (60004610)
溝口 到 東北大学, 歯学部・付属病院, 講師 (20200032)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | root resorption / orthodontic tooth movement / odontoclast / periodontal ligament fibroblast / abnormal root shape / hypomineralized dentin / cementblast / odontoblast / メカニカルストレス / 象牙質 / セメント質 / 破歯細胞 / 矯正的歯の移動 / 歯根膜 |
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| Research Abstract |
The purpose of this study was to examine the risk of root resorption during orthodontic treatment and develop the prevention method of that from the basic and the clinical background. Clinical studies showed almost 40% of patients that developed severe root resorption during orthodontic treatment had abnormally shaped roots before active treatment. To test the effects of deficiencies of mineral nutrients on the formation of roots and the development of tooth resorption during orthodontic tooth movement, 2 weeks-old Wistar rats were fed a low calcium diet during root development period and the molars were moved orthodontically. A hypomineralized dentin with interglobular dentin was observed in the experimental animals, but no significant difference was observed in the development of tooth resorption between control and experimental animals. Immunohistochemical studies showed cementblasts produced osteocalcin and glycosaminoglycans and have simillar characteristics with osteoblasts. The production of them was changed during orthodontic tooth movement and cementblasts suggested to be related with the formation of odontoclasts. In vitro studies showed human periodontal ligament (PDL) fibroblasts induced HSP 47,60,70 with the application of continuous compressive stress to protect cells from mechanical stress and regulated the formation of odontoclast-like cells from peripheral blood lymphocytes. In contrast, inhibitory effects of the topical administration of a bisphosphonate on root resorption incident to orthodontic tooth movement were observed in rats. These results indicate the risk of root resorption during orthodontic treatment may be related with the properties of the periodontium and the roots and some bone resorption inhibitory detergents can prevent it.
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