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Effect of Different Energy Densities of 915 nm Low Power Laser on the Biological Behavior of Human Gingival Fibroblast Cells In Vitro

Photobiomodulation is recognized as an effective method for adjunct therapy in periodontal treatments. Our purpose in this study was to investigate the effects of different energy densities of 915 nm diode laser on the viability and viability capacity of human gingival fibroblast cells. Cell samples were examined in five groups, including four irradiation groups with low‐level diode laser 915 nm, 1, 2, 3, 4 J cm−2 and a control group (no Laser irradiation). Cell viability and viability were measured 1, 3 and 5 days after irradiation by MTT and DAPI assay. Statistical differences between groups at any time were analyzed by one‐way ANOVA and a post hoc Turkey’s test. The cell viability and viability capacity increased on the third day at an energy density of 3 J cm−2; (P‐value = 0.007) and the fifth day at energy densities of 2, 3 and 4 J cm−2 was recorded compared with the control group (P‐value = 0.000). Also, a significant decrease in the viability and viability of irradiated cells with an energy density of 1 J cm−2 was found (P‐value = 0.033). According to our results, Photobiomodulation with 915 nm diode laser has a positive stimulating effect on the viability and viability capacity of human gingival fibroblast cells.