| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
On the mammal, the mineralization of mantle dentin is formed with the mineralization of the matrix vesicle. But the mineralization of circumpulpal dentin is formed by the mineralization that relates to collagen fibers. The spherical calcospherites were observed in the predentin of crown dentin. In the apical region of root dentin, the calcospherites were not observed and the calcified collagen fibers were observed. The species specificity was detected in the development and distribution of calcospherites. As compared with in the cementum covered lingual dentin of continuously growing teeth such as rat and rabbit incisors, and in the cementum covered root dentin uncontinuously growing teeth such as humans and bovine incisors, the form and the size of calcospherites were greatly different. In the marsupial opossum dentin, the calcospherites were only observed at the cervical region of crown. In the reptile crocodilian dentin, the size of the calcospherites was smaller than that of mammal
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, and the fiber-like structure was observed on the surface of calcospherites. On the Ca/P ratio of calcospherites in human, bovine and opossum, the significant difference had been found between the crown and the root of dentin. The difference was not found on the Ca/P ratio of calcospherites in the continuously growing teeth such as rat and rabbit, and polyphyodont crocodilian. It is considered that the difference of the mechanisms of teeth formation related to that of calcospherites formation. With the results of the analytical electron microscopy, except the main element of calcium and phosphorus, elements of Mg S, K, and Al were detected in the stage of calcospherite formation. It was clarified that Mg especially had the key role the formation of the calcospherites among small amount elements from the observation of the analysis electron microscope A lot of Mg was detected in the first stage of the formation of calcospherites. Mg may contribute to physicochemical stability of the apatite crystal. It seems that Mg takes part in the nuclear formation on the initial stage of calcospherites formation. Moreover, it is considered that the localization of S means the existence of the proteoglycan that is non-collagen protein in the calcospherites. It is judged that S of the sulfuric acid radical in the proteoglycan was detected. The calcospherites of crocodilian were small and S was distributed from the cervical region to the root region of dentin. It was considered that the proteoglycan controlled the formation of calcospherites because it took part in the formation of collagen fibers and has closer affinity with Ca. When a human molar was stained with the antiheparan sulfate antibody, the immune reaction attitude was different between the crown pulp and the root pulp. It is considered that this opinion is related to the difference in the form and development of calcospherites between the crown and the root dentin. The reaction was seen well in the region with which dentin was being firmed in the predentin of crown. The calcospherites existed in the mineralization front of dentin, and it was suggested that the form of calcospherites was related to the localization of the heparan sulfate. Less
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