| Project/Area Number |
05671662
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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 |
Surgical dentistry
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| Research Institution | Niigata University |
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Principal Investigator |
HAMAMOTO Yoshioki Niigata University, School of Dentistry, Assistant Professor, 歯学部, 助手 (40231526)
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| Co-Investigator(Kenkyū-buntansha) |
IZUMI Kenji Niigata University, School of Dentistry, Assistant Professor, 歯学部, 助手 (80242436)
SUZUKI Ichirou Niigata University, Dental Hospital, Lecturer, 歯学部・附属病院, 講師 (80179192)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | odontogenic epithelium / MNU, / amelogenin / Hertwig's root sheath / epithelial rests of Malassez / マラッセの上皮遺残 |
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| Research Abstract |
[Production of amelogenin by the enamel epithelium of Hertwig's root sheath]
The enamel epithelium of Hertwig's root sheath formed the epithelial islands, which resembled epithelial rests of Malassez, due to inflammatory stimulation of pulpitis. Parts of the epithelial cells, which were in contact with subsequently formed calcified fissue, showed columnar appearance. Immunohistochemical reactions were positive both in the cells and at the are between the cells and the calcified tissue. The findings suggestedthat the enamel epithelium of Hertwig's root sheath havethe potential of differentiation into ameloblasts.
[Experimental study on odontogenic tumors induced by local administration of MNU]
The mixture with the alginate impression material for dental use and MNU was injected on the bone surfaces of left mandibles. The inflammatory reactions were localized around the mixture, which was gradually resolved by macrophages. The odontogenic tumors, which resembled ameloblastoma, were occurred in cervical and bifurcational regions of molars more than 5 months after the injection. The tumors were confirmed to be derived form epithelial rests of Malassez. The incidence of occurrence of the tumors was nearly 100%.
[Co-culture of human ameloblastoma cells and calcified tissues from teeth]
The morphological changes of human ameloblastoma cessl in vitro was examined by the co-culture with fragments of teeth . The human ameloblastoma cells in vitro showed mono-layr seat like appearance, but they did not survive more than 1 month. There was no morphological change of the cells in theco-culture with the fragments of teeth within one month. It was suggested that long term survival of the ameloblastoma cells was important for the morphological changes.
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