Quantitative Analysis of Tooth Mineral Content by High Resolution Micro-computed Tomography

• Published in: International journal of oral biology Vol. 42; no. 4; pp. 155 - 161
• Main Authors: Song, Dae-Sung, Kim, Jung-Woo, Hwang, Hee-Su, Oh, Sin-Hye, Song, Ju Han, Kim, Il-Shin, Hwang, Yun-Chan, Koh, Jeong-Tae
• Format: Journal Article
• Language: Korean
• Published: 2017
• Subjects: Mineral concentration; Micro-CT; Tooth
• ISSN: 1226-7155; 2287-6618

Teeth and bones are highly mineralized tissues containing inorganic minerals such as calcium phosphate, and a growing number of evidences show that their mineral content is associated with many diseases. Although the quantification of mineral contents by micro-computed tomography(micro- CT) has been used in diagnosis and evaluation for treating bone diseases, its application for teeth diseases has not been well established. In this study, we attempted to estimate a usefulness of a high-resolution micro-CT in analysis of human teeth. The teeth were scanned by using the Skyscan 1172 micro-CT. In order to measure tooth mineral content, beam hardening effect of the machine was corrected with a radiopaque iodine-containing substance, iodoacetamide. Under the maximum resolution of $6.6{\mu}m$, X-ray densities in teeth and hydroxyapatite standards were obtained with Hounsfield unit (HU), and they were then converted to an absolute mineral concentration by a CT Analyzer software. In enamel layer of cusp area, the mean mineral concentration was about $2.14mg/mm^3$ and there was a constant mineral concentration gradient from the enamel surface to the dentinoenamel junction. In the dentin of middle 1/3 of tooth, the mean mineral concentration was approximately $1.27mg/mm^3$ and there was a constant mineral concentration gradient from the outer of root to the pulp side, ranging from 1.3 to $1.06mg/mm^3$. In decay region of dentin, the mineral content was gradually decreased from the intact inner side to the decayed surface. These results suggest that high-resolution micro-CT can be as a useful tool for non-invasive measurement of mineral concentration in teeth.