1990 Fiscal Year Final Research Report Summary
Investigation of the Pharmacological Effect of Calcium Hydroxide with a Rabbit Ear Chamber Technique
| Project/Area Number |
63480424
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Showa University |
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Principal Investigator |
WAKABAYASHI Hajime Showa University School of Dentistry, Department of Endodontics, Associate Professor, 歯学部・歯内療法学講座, 助教授 (90175688)
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| Co-Investigator(Kenkyū-buntansha) |
HORIKAWA Manami Showa University School of Dentistry, Department of Endodontics, Assistant Profe, 歯学部・歯内療法学講座, 助手 (70201762)
TUZUKI Nobuyuki Showa University School of Dentistry, Department of Endodontics, Assistant Profe, 歯学部・歯内療法学講座, 助手 (60217354)
FUNATO Akiyoshi Showa University School of Dentistry, Department of Endodontics, Assistant profe, 歯学部・歯内療法学講座, 助手 (60219087)
NAKMUURA Yukio Showa University School of Dentistry, Department of Endodontics, Lecturer, 歯学部・歯内療法学講座, 講師 (40207931)
TACHIBANA Hitoshi Showa University School of Dentistry, Department of endodontics, Lecturer, 歯学部・歯内療法学講座, 講師 (20146872)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Rabbit Ear Chamber / Calcium Hydroxide / Dystrofic Calcification / X-RAY Microanalyzer / IN-VIVO Observation / Root canal sealer / Microcirculation |
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| Research Abstract |
An improved rabbit ear chamber (REC) was used to investigate the dystrophic calcification after Ca(OH)_2 application on connective tissues. Ca(OH)_2 with saline was inserted into the REC and the change in microcirculation inside was observed under the vital-microscope with passage of time. Several minutes after the application, microvessels within the close vicinity to Ca(OH)_2 began to disappear. After 3 hours, at the border between the living tissue and liquefacted area, many precipitates were observed. They became large in both size and number to combine like a bank until 48 hours. SEM and EDX investigation revealed that these precipitates contained Ca, P, S,and Mg and they were produced by neutralization of Ca(OH)_2 with the tissue fluid. These precipitate bank had a high affinity with the microcirculation as long as 14 weeks. The tissue-side of the bank became a plate-like form, absorbing Ca and P from the tissue fluid. It seems that the bank affords a bandage for the exposed pulp tissue to begin the deposition of reparative dentine. The characteristic leature of the pharmacological effect of Ca(OH)_2 may be to make such a neutralized precipitates that introduces dystrophic calcification.
Therefore, the high alkalizing property and necrotized-tissue producing effect of Ca(OH)_2 were inevitable to make these precipitates, whereas these properties were thought to be negative. The Ca(OH)_2-containing root canal sealers, "Sealapex" and "Calvital", and the pulp capping agent "Dycal" produced the same precipitates. These medicine have all high alkalinity. However, the newly-developed root canal sealer, which constituents were Ca(OH)_2 and fatty acid, was neutral in pH and did not produce such precipitates. It need further experiments to determine which is a bette property as an endodontic materials, but we found out that there were two different types in so-called Ca(OH)_2-containing root canal sealers.
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Research Products
(8 results)
