The accuracy of quantifying the degree of hard tissue calcification using an electron probe micro analyzer, micro-focus X-ray computed tomography, and tissue sectioning methods

Objectives: Micro-focus X-ray computed tomography (& mu;CT) helps evaluate specimens without destroying it. However, its accuracy of quantifying bone mineral density remains to be fully elucidated. We aimed to verify the accuracy of calcification assessed by & mu;CT, by comparing the images of identical specimens obtained via different methods such as & mu;CT and electron probe micro analyzer (EPMA) analyses.Methods: The maxillae, mandibles, and tibiae of five-week-old male mice were analyzed. Calcification density was analyzed using & mu;CT. The right sides of the specimens were decalcified and processed for Azan staining. The left side of the specimens underwent elemental mapping for Ca, Mg, and P using EPMA.Results: & mu;CT revealed a significant increase in calcification levels in the following order: enamel, dentin, cortical bone, and trabecular bone. These results refiected the Ca and P levels observed in the EPMA analyses. & mu;CT demonstrated significant differences in the degree of calcification among the enamel tis-sues or dentin tissues, except for dentin in the maxillary incisors and molars. However, EPMA analysis did not demonstrate significant differences in the Ca and P levels among the same tissue samples.Conclusions: EPMA elemental analysis can be used to measure Ca and P levels for evaluating the calci-fication rate of hard tissues. Additionally, the study results validate the evaluation of calcification density via & mu;CT. Furthermore, & mu;CT can evaluate even minute differences in calcification rates compared with EPMA analysis.& COPY; 2023 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.