Effects Of Simulating Static Magnetic Field Of Magnetic Attachment On Human Gingival Fibroblasts And Human Periodontal Ligament Fibroblasts

With the development of technology, there is a trend toward the use of static magnetic field in medical diagnosis and therapy procedures. Considering this trend and lack of consensus on the biologic effects of static magnetic fields, it is of considerable interest to many researchers to advance in this study. Magnetic attachments, with their excellent retentive behaviors, have been widely applied in dental clinic. However, the uncertain effects of their static magnetic fields on local tissues elicit heated concerns of both clinicians and patients. Therefore, emphasis paid to their biological effects is considered necessary and important.In this study, human gingival fibroblasts (HGF) and human periodontal ligament fibroblasts (HPDLF) cultures were exposed to simulating static magnetic fields of magnetic attachment 4 days with flux density of 12.5mT, 125mT and 250mT both in 12h-expoure group and in 24h-exposure group. Controls were also set up. In order to identify the safety characteristics of static magnetic field, series of cellular parameters were examined and analyzed, such as cell morphology,functions, mutagenesis effects and activity of cellular superoxide dismutase (SOD) with Maleic Dialdehyde (MDA) content as well. The results showed as following:1. HGF and HPDLF cells exposed to both 12.5mT, 125mT, and 250mT static fields for periods of 12h per day or 24h per day did not exhibit differences in cell growth pattern or morphologic characteristics, neither in cell distribution, as compared with the control group.2. Under the observation of transmission electron microscope, no detectable changes were found in cellular microstructures of HGF and HPDLF in 12.5mT, 125mT or 250mT static magnetic fields, comparing with the control group.3. The growth situations of GHF in absence and presence of different intensities of static magnetic fields used in this study were consistent on the whole. While, clear-cut relationships between the exposure ways and effects, and later the intensities with effects were found in HPDLF (P<0.05), thus pointed out that strong magnetic field (250mT) with exposure 24h per day increased cell growth.4. The results showed increase induced by 24h-exposure to 250mT static magnetic field in terms of activity of alkaline phosphatase (ALP) in HPDLF (PO.05), while no corresponding effects were detected in HGF.5. No difference on cell cycle distribution, cell proliferation and apoptosis situation were observed under the static magnetic fields used in this study, as compared with the control group.6. Damages to cell chromosome and DNA in HGF and HPDLF under different intensities of static magnetic fields used in this study were not detected.7. Also, comparing with the control group, no differences of the activities of cellular superoxide dismutase (SOD) with Maleic Dialdehyde (MDA) contents in HGF and HPDLF were found under different intensities of static magnetic fields.Based on these findings, the study clearly demonstrated that static magnetic fields with intensities of 12.5mT, 125mT, and 250mT had no damage effects on both HGF and HPDLF. As far as the complex and diversity of biologic effects were concerned, furthermore study should be performed in terms of correct evaluation of biosecurity of static magnetic fields.