The Effect Of Pulsed Nd:YAG Laser Irradiation On Periodontal Ligament Fibroblast Cell Cultures

Periodontal Ligament Fibroblast Cell Cultures Objective: Studies have shown a high supportive effect of Nd:YAG laser using in combination with scaling and root planning, some other studies indicated that laser may damage the root surface and collateral periodontal tissue when certain energy levels are exceeded. The present study is to evaluate the effects of the Nd:YAG laser irradiation on the survival rate of human periodontal ligament fibroblast cell (PDLF) at different power and irradiation times settings, and compare the morphological change before and after the irradiation.Method: The PDLF cell was obtained from a female periodontal connective tissue explant, Cells were cultured on 96-well tissue culture plates. According to the irradiation time, the cell divided into 4 groups (10,20,40,60s), and in each group, according to the output energy, divided into 5 groups (0.5,1.0,1.5, 2,2.5W). Under each setting, 4 multi well cell cultures were laser irradiated and another 1 used as contrast. Took Photographs before and after irradiation. Counted the dead cell numbers and total cell numbers under a light microscope by means of trypan blue staining, calculate the survival rate of PDLF.Result: The result showed that with the setting of 10s and 20s, 0.5w; 20s,1.0w, no significant reduction of survive rates was found comparing with the control. With the increase of the power output and irradiation time , the laser caused significant (P<0.05, t-test) reductions of survival, rate of cell, While Irradiation time was more relevant to this reduction than the power output. Withlower time and output setting, no obvious morphological change of cell was found, while with higher setting, morphological change of PDLF was found till the death of the cell.Conclusion: It indicate that when Nd:YAG laser used for periodontal pocket decontamination, if the power output and the irradiation time are not adequate, the laser beam may cause damage the periodontal ligament fibroblast cell and cause negative effect to collateral periodontal tissues.