Effect of 810, 940 nm Laser Irradiation with Different Energy Densities on Periodontal Ligament Stem Cells

Background and Aim: At low intensities, laser therapy has shownbiostimulatory effects at cellular levels. This effects may be used in tissueengineering treatments using stem cells. However, the application ofappropriate dosimetric parameters is of great importance in achievingfavorable results. The purpose of this study was to determine the effectof different fluences (energy densities) of near infra-red diodes laserswith wavelengths of 810, 940 nm typically used in dentistry on theproliferation and survival of Periodontal ligament derived stem cells. Methods: In this study, periodontal tissue remnants of human teethextracted for orthodontic purposes were used for isolation of periodontalligament stem cells. The mesenchymal nature of the isolated cells wasdetermined using CD45, 90, 105 surface markers. Third passage cellswere then irradiated by laser radiation of 810 (L1), 940 (L2) nm, withenergy densities of 0.5, 1.5 and 2.5 J/cm2, 100 mw output powers. Anon-irradiated group was considered as control. Cellular viability wasmeasured after 24 hours of exposure to a single session of laser irradiationand proliferation was measured 24, 48, 72 hours after exposure.Propidium iodide (PI) staining was used to identify any pyknotic nucleior nuclear fragmentation 72 hours after irradiationResults: The isolated cells were positive for CD105 and CD90 andNegative for CD45. An increase in cellular viability 24 hours afterlaser irradiation was only observed with the 940 nm laser and 2.5 J/cm2 energy density. This increase was statistically significant comparedto the other settings and control group (P< 0.001). The proliferation ofcells also showed a statistically significant increase in the 940 nm, 2.5 J/cm2 irradiated group at all time points in comparison to other groups andcontrol(P<0.001). PI staining showed no adverse effect in cell nuclei inany of the groups.Conclusion: In this study, 940 nm diode laser with an energy densityof 2.5 J/cm2 significantly increased PDLSC viability and proliferationcompared to the other settings and control group.

کلیدواژه ها:

Photobiomodulation ، Periodontal ligament ، Stem cell