1997 Fiscal Year Final Research Report Summary
Immunohistochemical study on the odontoblast differentiation during reparative dentinogenesis
| Project/Area Number |
07672074
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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 | Niigata University |
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Principal Investigator |
AYUKAWA Yukio Niigata University, School of Dentistry, Assistant Professor, 歯学部, 助手 (00183145)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIBA Kunihiko Niigata University, Dental Hospital, Assistant Professor, 歯学部・附属病院, 助手 (30220718)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Reparative dentinogenesis / Odontoblasts / Extracellular matrix / Basement membrane / Epithelial-mesenchymal interactions / Dental caries / Antigen presenting cell / Immunohistochemistry |
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| Research Abstract |
The aim of this study is to elucidate mechanisms by which pulp cells differentiate into odontoblasts during reparative dentinogenesis. The results were as follows :
1. Fibronectin was present in the odontoblast layr during all stages of dentinogenesis. Fibronectin-positive fibrous structures between odontoblasts would be closely related to odontoblast differentiation and dentinogenesis. Labeling for decorin was observed in odontoblast cell bodies and its processes located in predentin. No reaction was observed in predentinal matrix, however, staining was intense along the calcification front and dentinal tubules, suggesting that decorin might regulate the mineralization of dentinal matrix.
2. During reparative dentinogenesis, after pulp was capped with Ca (OH) 2, fibronectin associated with the initially formed calcified layr might play a mediating role in adhesion of pulp cells. and their differentiation into odontoblasts. Odontoblasts under carious lesions reacted positively to decorin
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, whereas the dentinal matrix and tubules affected by caries did not. Growth factors binding to decorin would mediate the increased levels of dentin matrix secretion in dentinal caries by being released from dentin during this demineralization.
3. The distribution of odontoblast processes in the human coronal dentin was studied by using fluorescence staining and transmission electron microscopy. Odontoblast processes would be limited to the inner dentin of fully erupted human teeth.
4. The distribution of class II major histocompatibility complex (MHC) antigen-expressing cells was analyzed in human teeth. Human dental pulp is equipped with immunologic defense potential prior to eruption. In the initial stage of caries infection, an immunoresponse mediated by class II-expressing cells is initiated. Co-localization of cytoplasmic processes of HLA-DR-positive cells with odontoblast processes in the dentinal tubules suggests a rule in reparative dentinogenesis.
5. The expression and localization of laminin-5 were temporally and spatially regulated during mouse tooth development. The temporo-spatial changes in basement membrane composition might be related with tooth morphogenesis and cytodifferentiation. Less
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