The effects of different 650 nm laser diode irradiation times on the viability and proliferation of human periodontal ligament fibroblast cells

Abstract

Background: Endo-perio lesions are clinical manifestations of inflammation in the periodontal and pulp tissue. Damage to the periodontal ligament can inhibit its ability to regenerate. Therefore, laser therapy use is expected to improve the prognosis with regard to healing lesions. Unfortunately, the duration of irradiation during laser diode therapy can influence the viability and proliferation of human periodontal ligament fibroblast (hPDLF) cells. Purpose: This study aims to determine the effects of different irradiation exposure times of the 650 nm laser diode of the pulsed mode type on the viability and proliferation of human periodontal ligament fibroblast cells. Methods: This study constituted a laboratory experiment on hPDLF cells using 650 nm laser diode irradiation. Six groups formed the research subjects in this study, namely; two control groups, two radiation groups respectively subjected to irradiation exposure of 15 seconds and 35 seconds duration followed by 24-hour incubation, and two radiation groups exposed to irradiation for 15 and 35 seconds respectively followed by 72-hour incubation period. The viability and proliferation of those cells were subsequently calculated by ELISA reader, while the data was analyzed by means of one-way ANOVA and Tukey tests. Results: The significance value of the viability scores between the 15-second irradiation group and the 35-second irradiation group was less than 0.05, indicating that there was a significant difference between these treatment groups. Similarly, the significance value of proliferation scores between the 15-second irradiation group and the 35-second irradiation group was less than 0.05, again indicating a significant difference between these treatment groups. Conclusion: Irradiation using a 650 nm laser diode 15 seconds and 35 seconds in duration can induce an increase in the viability and proliferation of hPDLF cells.

In Vitro Effect of Photodynamic Therapy with Indocyanine Green Followed by 660 nm Photobiomodulation Therapy on Fibroblast Viability

“…In our study, laser power, duration of laser irradiation and the distance between the radiation source and the culture medium all increased the dosage of laser received by fibroblasts compared with their study. Nonetheless, their results were similar to our findings, which further confirms the positive effects of PBM in visible light spectrum on the viability of fibroblasts (30).…”

“…Difference between their results and ours can be due to the (I) difference in laser density and brand of laser handpiece; (II) difference in culture medium collection; and (III) mechanism of effect of 780 nm laser on cells including cell damage, induction of rotation and vibration of cells and consequent release of growth factors such as FGF-B (27). The effect of different laser irradiation times on PDL fibroblasts was evaluated by Ismiyatin et al (2019). They assessed the effect of 650 nm PBM with 20 mW power irradiated for 15 and 35 s on fibroblasts and concluded that PBM with 650 nm for 15 and 35 s significantly increased the viability of fibroblasts.…”

In Vitro Effect of 445 nm Blue Laser and 660 nm Low‐Level Laser on the Quantity and Quality of Human Gingival Fibroblasts

“…Several parameters, including the wavelength, energy density, irradiation time and area under laser irradiation, are effective in the efficacy of low‐power lasers. Previous studies have shown that laser radiation plays an important role in increasing fibroblast proliferation, and the wavelength of 600‐700 nm is considered the appropriate wavelength to stimulate the proliferation and differentiation of fibroblasts (33).…”

“…Cell membrane changes by calcium displacement, pH changes, activation of CAMP and DNA duplication lead to protein synthesis. In this way, cellular responses are transported from the cell surface to tissues and organs with effects such as anti-inflammatory, anti-edema, analgesic, cell proliferation, neovascularization, accelerated repair and the shift to aerobic metabolism (33).…”