Fig. 2

Time-course analysis of osteocyte death in the mouse model of orthodontic tooth movement (OTM). a Hematoxylin and eosin (H&E) staining of horizontal sections with periodontal tissue and distobuccal root of the maxillary left first molar after OTM in WT mice. Upper left image: the rectangles of 400 μm × 200 μm indicate the region of interest (ROI) on the compression and tension sides. Black arrows indicate the direction of force. Scale bar = 100 μm. Other images: high-magnification images of ROIs on the compression and tension sides. White arrowheads indicate normal osteocytes, orange arrowheads indicate dying osteocytes, and red arrowheads indicate empty lacunae. Scale bar = 50 μm. b Percentage of normal osteocytes (white), dying osteocytes (orange), and empty lacunae (red) (n = 6). c Transmission electron microscopy (TEM) analysis on days 0 and 6 after OTM in WT mice. Yellow arrows indicate empty lacunae. Scale bar = 2 μm. M, mesial side; D, distal side; a, alveolar bone; p, periodontal ligament; r, root.