| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Yoshiro Dental hospital, Tokyo Medical and Dental University, Lecturer, 歯学部附属病院, 講師 (20292980)
SOMA Kunimichi Graduate School, Tokyo Medical and Dental University, Professor, 大学院・医歯学総合研究科, 教授 (10014200)
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| Research Abstract |
It is urgently necessary to investigate the effect of aging on the periodontal ligament (PDL) because the number of elder patients in orthodontic practice is increasing. Recently, many reports in the medical field have revealed that the activities of various organs change and oxidative stress increases with aging. From this knowledge, we supposed that oxidative stress in PDL might increase with aging. Nitric oxide (NO), which is one of the bearers of oxidative stress, is erased by antioxidant agents. On the other hand, various animal experiments have clarified that external forces such as occiusal and orthodontic forces recover and improve the function of the PDL. In other words, the signals transmitted by some mechanical stresses will recover and activate the stress induced changes of PDL in cellular level.
Using some rat experiment models, the responses of the PDL to occlusal and orthodontic forces were investigated with enzyme-and immunohistochemistry.
The results were as follows: when hypofunctional PDL recovered with occlusal force, monocyte-macrophages played an important role, and eNOS and iNOS were expressed. Light and continuous orthodontic force changed the NOS activity in the PDL at shorter duration than that in some former reports. Furthermore, we examined the effect. of aging on the blood vessels in rat gingiva and revealed the change, pf geometry. This result got a foothold in analyzing the relationship between aging and mechanical stress. Finally, the signal transduction of optimum mechanical stress for activation of PDL cells and osteoblasts was partially elucidated in some in vitro studies
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