Evaluation of permanent and primary enamel and dentin mineral density using micro-computed tomography

The present study was performed to investigate the mineral density distribution in enamel and dentin for both permanent and primary teeth and to establish the standard density per tooth type using micro-computed tomography (CT). Fifty-seven extracted human teeth (37 permanent, 20 primary) were evaluated in the present study. The enamel and dentin mineral densities in the extracted teeth were measured using micro-CT. Cubic regression curves were used to determine the mineral density distribution in the enamel and dentin for each tooth type. The mean values, distributions, and regression equations of the mineral densities were obtained. The mean mineral density values for permanent enamel and dentin were significantly higher than those for their primary counterparts for each tooth type. In the present study, we demonstrated the distribution of mineral density in sound enamel and dentin and attempted to determine the standard mineral density for each tooth type using micro-CT. The mineral density distributions found in this study contribute to our understanding of the mechanical properties of enamel and dentin. A positive correlation suggests that the systemic bone mineral density could be predicted based on the analysis of exfoliated teeth, such as in patients with hypophosphatasia. The present results may be useful in establishing a numerical standard for the mechanism involved in root fracture and for early detection of root fracture risk.