| Project/Area Number |
01570992
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Higashi-Nippon-Gakuen University |
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Principal Investigator |
YAJIMA Toshihiko Higashi-Nippon-Gakuen Univ. Dent. Sch., Dept. Oral Anat., Prof., 歯学部, 教授 (10018749)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1989: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Periodontium / Cementoblast / Epithelial rests of Malassez / Collagen degradation / Collagen phagocytosis / Acid phosphatase / Alkaline phosphatase / Remodeling of periodontium / コラゲン貪食 / コラゲン改造機構 |
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| Research Abstract |
For the remodeling and renewal of connective tissues in the periodontium, the orderly and specific removal of nonfunctional, denatured collagen fibrils and their replacement with newly synthesized collagen are needed. In physiologic tooth eruption and migration, it has been suggested that the continuous remodeling of periodontal ligament fibrils occurs at the ligament-cementum and ligament-bone interfaces. Few data are available on the mechanism and regulation of these processes and the role of cementoblasts in the remodeling is still unknown.
Male rats of the Wister strain (3-week to 6-month-old) were used. The periodontal ligament-cementum interface of rat mandibular molars was investigated by electron microscopy.
Evidence supporting cementoblast phagocytosis of collagen fibrils of the periodontal ligament was found. The collagen-containing vacuoles were frequently observed within cementoblasts in association with an acid phosphatase activity. The presence of acid phosphatase activity in these vacuoles suggested that intracellular degradation of collagen was occurring. In addition, alkaline phosphatase activity was observed on the limiting membrane of collagen-containing vacuoles being formed and was suggested to be related to differentiation and formation, or conformational changes of the phagosome membrane. The epithelial rests of Malassez also phagocytosed collagen fibrils at this area.
Our results showed that cementoblasts exhibited collagen phagocytic activity and suggest that cementoblasts may play an important role in the physiological remodeling and metabolic breakdown of the collagen at the periodontal ligament-cementum interface. The activity of collagen-resorbing can be considered to be shared by fibroblasts and cementoblasts.
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