Figure 3

Changes in a horizontal section of the maxillary right first molar over time during experimental tooth movement. HE-stained images on days 0 (a), 1 (b), 3 (c), 7 (d), 14 (e), and 21 (f). Due to the orthodontic force, the periodontal ligament was compressed on the compression side (*) and stretched on the tension side (†). Arrows indicate the direction of tooth movement. MP proximal palatal root, MB proximal buccal root, DP distal palatal root, DB distal buccal root, AB alveolar bone, PDL periodontal ligament, P pulp cavity, m bone marrow. Scale bar, 200 µm. Time course changes of the width of the PDL on the compression and tension sides on days 0, 1, 3, 7, 14, and 21 (g). ^ap < 0.01 vs. day 0; ^bp < 0.05 vs. day 0; ^cp < 0.01 vs. day 1; ^dp < 0.05 vs. day 1; ^ep < 0.01 vs. day 3; ^*p < 0.05 vs. compression side (n = 4). Black bars, compression side; gray bars, tension side.