| Project/Area Number |
17592005
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | The Nippon Dental University |
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Principal Investigator |
KAWASAKI Kohichi The Nippon Dental University, School of Life Dentistry at Niigata, Professor (90013961)
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| Co-Investigator(Kenkyū-buntansha) |
KITAJIMA Kayoko The Nippon Dental University, School of Life Dentistry at Niigata, Assistant Professor (00177841)
田中 幹久 日本歯科大学, 新潟生命歯学部, 助手 (00409236)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2005: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | wide open apex / immature permanent teeth / Hertwiig's epithelial sheath / apexification / apical closure mechanism / FR-Ca / pulpless monkey teeth / histologic study / 根未完成永久歯 / 幼若歯髄 / 歯根形成能 / 根尖閉鎖機転 / アペキソゲネーシス / 水酸化カルシウム / 器械的・細菌的刺激 / 歯髄歯根膜損傷 / 根尖創傷治癒機転 |
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| Research Abstract |
Pulp and periapical responses were evaluated histopathologically in teeth of 3~4 year-old monkeys with incomplete root formation and periapical lesions in order to examine the occurrence mechanism of apical closure by a new calcified tissue deposition with FR-Ca.
The periapical lesions were made by allowing the root canals to be opened and exposed to the oral environment for a period a month to above a year.
Radiographs showed periapical rarefactions over the areas of most teeth.
One-visit FR-Ca apexification therapy was performed. Root canal debridement and preparation by large K-files were employed. Instrumentation was done carefully to 1~2mm short of the radiographic apex. FR-Ca was placed to occupy about 1~2mm of the apical canal space with a Lentulo spiral. Coronal portion was condensed with FR-Ca and gutta percha cones. The cavities were sealed with light cured glass ionomer cement.
Control group was non-treated vital teeth.
After 1~2 months, the animals were sacrificed by perfusion with 10 % formalin and the jaws dissected and fixed therein.
After decalcification, the blocks were cut into 7μm thick sections and stained with HE stain and other stain techniques. Undecalcified teeth were observed with MicroCT apparatus.
In FR-Ca after 4 weeks, new formation of cementum-like hard tissue on the sealers became obvious. In a tooth of 3.5 months after pulp injury and oral contamination, the apical pulp tissue within the root canal was a zone of granulation tissue. In the apical area. Cementum-like calcific barrier had been formed despite of no root canal filling. It can be concluded from the specimens examined in this study that there appears to be a repair process that is independent of Hertwig's epithelial root sheath.
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