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Figure 4. Osteoclastogenesis and tooth movement. Photo images of osteoclasts. TRAP-positive multinucleated cells were observed around the teeth in the tooth-movement group (a) and in the OPG-transfection group (b). Periodontal tissues of the mesiopalatal roots of the upper first molars were examined in serial cross-sections of the molars at a bifurcation level. TRAP-positive multinucleated cells that formed resorption lacunae on the alveolar bone surface adjacent to the mesiopalatal roots of the upper first molars were counted. Representative photographs of 6 sections of both groups are shown. Bar = 100 µm. (c) Number of osteoclasts in the periodontium. TRAP-positive multinucleated cells that formed resorption lacunae on the alveolar bone surface adjacent to the mesiopalatal roots of the upper first molars were counted. The results are expressed as the mean ± SD (N = 6). (d) Time course of changes in tooth movement. N = 8 and 9, respectively (tooth-movement group, OPG-transfection group). No tooth movement to the palatal side was observed in both control and mock groups (data not shown). (e) Data are presented as percent inhibition of tooth movement (OPG-transfection group/tooth-movement group) in each day. *P < 0.05; **P < 0.01; ***P < 0.001.
