Fig. 2

Representative examples of three-dimensional (3D) micro-CT (μCT) images and the distance of OTM to display the mesial movement of the M1. Comparing the four study groups (control-non-OTM, control-OTM, hypoxia-non-OTM, and hypoxia-OTM), a significantly higher distance of tooth movement can be observed in the hypoxia-OTM group. The morphometric parameters of the trabecular bone for quantitative analyses and the area of interest are shown in the sagittal section. No significant difference is observed between control-OTM and hypoxia-OTM. (A) Occlusal and buccal views of OTM compared between control and hypoxia groups on both non-OTM and OTM sides. Scale bar, 1 mm. (B) Representative image of an OTM measurement. The distance between the most distal point of the upper right M1 crown and the most mesial point of the M2 crown is shown. Scale bar, 1 mm. (C) Comparison of the OTM distance between the control-OTM and hypoxia-OTM groups. n = 9; mean ± standard deviation (SD); * p < 0.05. (D) Analysis of the 3D microarchitecture using μCT scans of the trabecular bone. Trabecular thickness (Tb.Th), bone volume fraction (BV/TV), trabecular separation (Tb.Sp), trabecular number (Tb.N), and bone mineral density (BMD) are compared among the four study groups control-non-OTM, control-OTM, hypoxia-non-OTM, and hypoxia-OTM. n = 9; mean ± SD; * p < 0.05. (E) Representative image of the region of interest (ROI) for analysis. The rectangular volume size of 400 µm × 400 µm × 1400 µm is located in the distal area of the alveolar bone adjacent to the mesial root of M1. The evaluated area is 200 µm from the root surface. Scale bar, 1 mm.