Objective To evaluate the biologic effects of simulating static magnetic field of magnetic attachment on human periodontal ligament fibroblasts（HPDLF）. Methods HPDLF were cultured in vitro and exposed to simulating static magnetic fields of magnetic attachments for 4 days with magnetic flux density of 12.5, 125 and 250 mT respectively, while the control group free of additional static magnetic field was also set up. The activities of cellular alkaline phosphatase（ALP） and superoxide dismutase（SOD）were measured with a spectrophotometer, and cell cycle was analyzed by flow cytometry. Results An increase were detected, induced by 250 mT static magnetic field exposure for 4 days in terms of activity of ALP in HPDLF, as compared with the control group（P0.05）. Also there were no statistical differences observed on cell cycle distribution（P >0.05） or cell proliferation index（P >0.05） under such static magnetic fields. Conclusion The static magnetic fields of magnetic attachment used in this study have improved the activity of ALP, and do little inference to the activity of SOD and the cell cycle distribution.
