Abstract
Hydroxyapatite is the principal component of human teeth and its crystallinity is one of the resistant factors against acid agents. A decrease in crystallinity would impair the resistance to acid and dental caries as well. The relationship between Ca/P ratio and crystallinity in human dentin is not yet well understood. In this study, the contents of Ca and P of human dentin were obtained by atomic absorption analysis and colorimetric analysis, and Ca/P ratios were then calculated. The crystallinity of the dentin was also analysis with micro-region X-ray diffraction. The relationship between the Ca/P ratio and crystallinity was discussed. The results were obtained as follows
1. According to the data obtained from 18 teeth the Ca/P ratios were found to be related to the tooth type and the location in the dentin.
2. No differences in the distribution of the Ca/P ratio in dentin with incomplete and complete teeth sets of teeth.
3. X-ray diffraction intensity of the crystalline varied depending on its location in the dentin.
4. It can be concluded that the Ca/P ratio was interrelated to the crystallinity in the dentin.
