DEVELOPMENT OF A NEW ENAMEL BIOPSY METHOD BY ESCA

采用化学分析电子能谱法（ESCA）对牙齿羟基磷灰石{Ca_<10>(PO_4)_6(OH)_2}进行了分析。通过对人声音牙釉质和牙本质Ca、P、O的定量分析，认识到牙齿之间、牙釉质和牙本质之间羟基磷灰石晶体组成和结构的差异。在这项研究中，我尝试开发一种新的牙釉质活检方法，使用ESCA来阐明决定龋易感性的牙齿状况。使用抛光盘和抛光条从患者牙齿上获得极少量样品（0.1mg）。患者牙釉质Ca/P比值与拔牙牙釉质Ca/P比值一致。然而，患者牙釉质的氧与磷和氢的结合比率，被认为是确定患者牙齿龋易感性的重要因素，却无法获得。我将此失败归因于抛光盘和抛光条中Ca， P和O等牙齿成分的污染以及获取样品的方法。然后，我认识到钛合金作为不含牙齿成分的材料的实用性。此外，我改进了通过提供条带上的细凹槽来获取样品的方法。根据这些结果，我开发了使用钛合金作为带材基材的方法，以获得不损坏齿基板的样品。为了建立ESCA牙釉质活检方法，有必要对条带上钛合金的厚度进行一些改进。

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.