1986 Fiscal Year Final Research Report Summary
Studies on the Pulpal Responses to the Dental Materials Using Germfree Rats
| Project/Area Number |
59440079
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
KOBAYASHI Chihiro Tokyo Medical and Dental University, 歯学部, 講師 (80126226)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Toyoaki Tokyo Medical and Dental University, 歯学部, 助手 (90167792)
SUNADA Imao Tokyo Medical and Dental University, 歯学部, 教授 (50005013)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Germfree Rat / Composite Resin / Bacterial Endotoxin / Perforation / Implant / Thermal Injury / Osteo-Dentin |
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| Research Abstract |
1. The response of the exposed pulp to composite resin was investigated in germfree rats. The results indicated that composite resin had an irritating potential especially to the circulatory systems of the rat molar pulp.
2. Bacterial endotoxin was applied to the root canal of germfree rats and the toxic effects of endotoxin on periapical tissue were investigated. Resorption of the periapical alveolar bone was observed, but irritation of the endotoxin seemed to decrease by the formation of the periapical barrier consisting of dense connective tissue and cementum deposite, then the resorbed alveolar bone was regenerated.
3. Perforated site of the floor of germfree rat molar pulp chamber were treated with various materials and the results were histopathologically evaluated. Inflammatory responses were weak in control and amalgam group, and severe in Ca <(OH)_2> , hydroxyapatite and zinc oxide eugenol cement group. Control and hydroxyapatite group seemed to have some possibility of sealing the perforated site with the calcified tissue.
4. Experiments were performed to make a model of pulpitis following periapical lesion under an aseptic condition using conventional rats. To necrotize the pulp, thermal injury by soldering iron or mechanical injury by luxation was applied to the rat molar. Injured pulps were necrotized, then entire pulp chambers were filled with osteo-dentin, although periapical inflammation was not observed in both experimental groups.
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