| Project/Area Number |
61480417
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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 |
小児・社会系歯学
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| Research Institution | Osaka University |
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Principal Investigator |
SOBUE Shizuo Osaka University, Faculty of Dentistry, Professor, 歯学部, 教授 (60029973)
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| Co-Investigator(Kenkyū-buntansha) |
MORISAKI Ichijiro Osaka University, Faculty of Dentistry, Assistante Professor, 歯学部, 講師 (30116115)
OOSHIMA Takashi Osaka University, Faculty of Dentistry, Associate Professor, 歯学部, 助教授 (80116003)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥4,300,000 (Direct Cost: ¥4,300,000)
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| Keywords | Enamel / Posteruptive maturation / Bovine enamel / Tetracalcium phosphate / <alpha>etricalcium phosphate / Cement / pH / Solubility / Comresive strength / OH-apatite / リン酸緩衝塩類溶液 / エナメル質の成熟 / 赤外分折 / トレーセーリエレメント / 結晶性 |
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| Research Abstract |
The following results were obtained from the studies on the process of enamel maturation using bovine teeth. 1) During the stage of amelogenesis, great increases of calcium and phosphorus concentrations in the enamel powder were observed, while carbonate, fluoride and organic substances showed a marked decrease in the same specimen. The crystallinity of enamel apatite, crystal growth in the a-axis direction increased but in the c-axis direction almost complete, at that time. 2) In the early stage of root formation, the concentrations of calcium and phosphorus were still increasing. However, the rates of their increase in this stage were lower than in the stage of amelogenesis. Also there were no change in the concentrations of carbonate and fluoride. The crystal growth in the a-axis direction or the decrease of organic substances in the enamel powder was found to be at the same rate as in the first stage. 3) In the late stage of root formation, there was no change in the concentration
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of the constituents and the crystal growth. 4) During the stage of the stage of tooth eruption, concentrations of calcium and phosphorus increased while those of the carbonate and organic substances decreased. Both of those changes were less than in the stage of amelogenesis.
Physical and chemical properties of tetracalcium phosphate ( 4CP ) and <alpha>-tricalcium phosphate (<alpha>-TCP ) cements were compared. 4CP or <alpha>-TCP was mixed with 45% citric acid solution at a powder-liquid ratio of 1.5(w w). To determine the acidity of the cements, changes in the pH of 0.5 ml of distilled water in contact with each cement surface was monitered. 4CP cement gave the highest pH, ranging from 4.75 to 5.23, among the 4 types of cement tested. The measured pH values of <alpha>-TCP and polycarboxylate cement were 4.02 to 4.22 and 4.14 to 4.62,respectively Compressive strengths of both 4CP and <alpha>-TCP cements fullfilled the requirement of ADAs No.61. When immersed in phosphate buffered saline, 4CP and <alpha>-TCP cements showed high solubility but no changes in the compressive strength for 7 days. Less
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