DEVELOPMENT OF A NEW ENAMEL BIOPSY METHOD BY ESCA

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Electron Spectroscopy of Chemical Analysis (ESCA) was used as a new method for analysis of tooth hydroxyapatite {Ca_<10>(PO_4)_6(OH)_2}. By quantitative analysis of Ca, P and O of human sound enamel and dentin, I recognized the differences of the composition and structure of hydroxyapatite crystal among teeth as well as between enamel and dentin. In this study, I attempted to develop a new enamel biopsy method using ESCA to elucidate the tooth condition which determines caries susceptibility.The extremely small amount of samples (0.1mg) were obtained by using the polishing disk and strips from the patients' teeth. The Ca/P ratio of the patients' enamel was consistent with that of enamel in the extracted teeth. However, the ratio of oxygen bound to phosphorous and bound to hydrogen of the patients' enamel, which is thought to be an important factor for determination of caries susceptibility of the patient's tooth, could not be obtained. I attributed this failure to the contamination of the tooth components such as Ca, P and O in the polishing disk and strips and the method of getting the samples. Then, I recognized the usefulness of titanium alloy as the material which does not contain the tooth components. Moreover, I improved the method to obtain the samples by providing the fine grooves on the strips.Following these results, I developed the method using titanium alloy as the base material of the strips to get the sample without the damage of tooth substrate. The some improvements concerned with the thickness of titanium alloy on the strips are necessary to establish the enamel biopsy method using ESCA.