Using a model of experimental occlusal trauma in mice, we investigated cytological kinetics of periodontal ligament by means of histopathological, immunohistochemical, and photographical analysis methods. At furcation areas of molar teeth in the experimental group on day 4, the increase of cells in periodontal ligament was seen. The cells with a round-shaped nucleus were deeply stained in the hematoxylin-eosin. Ki67 positive nuclei showed a prominent increase in the experimental groups on days 4 and 7. Green Fluorescent Protein (GFP) positivity also revealed cell movement, but this action was slightly slow compared to Ki67 staining specimens. It was indicated that the homeostasis is mechanism of periodontal ligament receiving the excessive occlusal loading was promoted by osteoclasts and macrophages from bone-marrow-derived cells migrated to the periodontal ligament. The remodeling of periodontal ligament with the acceleration of cell growth was evoked from the experiment for the group on day 4 and after day 7. The findings suggested that periodontal ligament at furcation areas of molar teeth in occlusal trauma model was recovered by using both of the cells in situ and the bone-marrow-derived cells.2015博士（歯学）松本歯科大
