1994 Fiscal Year Final Research Report Summary
High-resolution Electron Microscopy of Enamel Crystals in Erupted and Unerupted Fluorotic Teeth
| Project/Area Number |
05454492
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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 |
Morphological basic dentistry
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| Research Institution | TOKYO DENTAL COLLEGE |
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Principal Investigator |
YANAGISAWA Takaaki Tokyo Dental College, Prof, 歯学部, 教授 (10096513)
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| Co-Investigator(Kenkyū-buntansha) |
TOHDA Hisako Tokyo Dental College, Lecturer, 歯学部, 講師 (80085828)
MIAKE Yasuo Tokyo Dental College, Associate Prof., 歯学部, 助教授 (00157421)
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| Project Period (FY) |
1993 – 1994
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| Keywords | fluoride / dental fluorosis / enamel / opical microscopy / polarized microscopy / microradiography / microanalysis / high-resolution electron microscopy |
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| Research Abstract |
Surface enamel of dental fluorosis obtained from human and pig were studied by means of optical and polarized microscopy, microradiography, electron-probe-and ion-microanalysis, X-ray and electron diffraction, and high-resolution scanning and tranmission electron microscopy.
Fluorotic enamel surfaces were generally cloudy to opaque loosing their translucency. An extensively hypomineralized area having lost negative birefringence extended from the inner enamel to the outermost surface layr. The hypomineralized area contained sparsely arranged, elongated hexagonal crystals and indicating either no or low fluoride content. The outermost layr, on the contrary, was mineralized to a high degree and showed negative birefringence. This highly mineralized layr was composed of many large elongated hexagonal crystals and extremely small regular and/or irregular hexagonal crystals. Large crystal had so-called central dark line. Lattice intervals of the large and the small crystals were 0.817nm and 0.812nm on their (001) crystalline planes, respectively. A high fluoride concentration was determined in the highly mineralized outermost surface layr.
These findings obtained from fluorotic enamel in this study suggest that the highly mineralized outermost surface layr contains hydroxyapatite, fluoridated-hydrxyapatite and fluorapatite. And fluorapatite crystals form in the outermost enamel befor eruption and increase in their number after eruption.
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