Effect of Nd: YAG Laser Irradiation on MC3T3-E1

Abstract

Purpose: The Nd: YAG laser has been widely used for periodontal pocket irradiation. In a lot of cases, the bottom of the periodontal pocket was close to the alveolar bone. The purpose of this study was to investigate the morphological effect of Nd: YAG laser irradiation on the MC3T3-E1 cell by different Nd: YAG laser irradiation settings. Methods: MC3T3-E1 cells were cultured with 10% FBS α-MEM medium and were irradiated using the Nd: YAG laser. The parameters in laser delivery were 3 groups; control, 100 mJ×30 pps×10 seconds and 200 mJ×30 pps×10 seconds. Following irradiation, cells were cultured for 24 hours. The cell number and migration assay were measured. The cell cultures were analyzed by morphological examination under a phase-contrast microscope and scanning electron microscope (SEM). Results: The number of 100 mJ×30 pps×10 seconds was significantly increased (p<0.001) ; however, 200 mJ×30 pps×10 seconds was significantly decreased (p<0.001) compared with control. It was detected that the cell migration ability of 200 mJ×30 pps×10 seconds was significantly decreased compared with control and 100 mJ×30 pps×10 seconds. A significant decrease in cell numbers was detected in 200 mJ×30 pps×10 seconds (p<0.05). We observed the cellular damage of cultured MC3T3-E1 induced by Nd: YAG laser irradiation, comparable with control by SEM. However the damage could not be detected by phase-contrast microscope. Conclusion: Our study demonstrated the cell damaging effects of the Nd: YAG laser with high power irradiation. It was shown that the difference of laser irradiation settings makes the cell function worse. It proved that dentists need to understand the potential hazard of laser application in periodontal treatment.