Photobiomodulation with 940 nm laser diode: effect on the interleukin 6 expression after orthodontic initial archwire activation

Abstract

To evaluate the effect of photobiomodulation (PBM) during the initial stage of orthodontic treatment, measuring levels of IL-6 in gingival crevicular fluid (GCF), and comparing to a control group of teeth. Forty-four first premolars were orthodontically treated with passive self-ligation Damon Q (Ormco, Orange, CA, USA) brackets and 0.014 CuNiTi archwires. Sides were randomly assigned to a non-irradiated control group and experimental group (n = 22) treated with 940 nm, 0.1 W, and 2 J for 20s/surface. Gingival crevicular fluid was obtained before treatment and 24 h after; a third sample was obtained immediately after a second laser irradiation. IL-6 concentration was measured by enzymatic immunoassay. The basal concentration of IL-6 in the control group (3.194 ± 0.71 pg/μl) was higher than in the experimental group (2.923 ± 0.48 pg/μl) and was reduced 24 h after the initial archwire placement. In the experimental group of teeth, 24 h after and after the first laser application, the levels were lower. However, the values obtained following the second laser application, evaluating immediate effect, presented a mild increment. The difference between control and experimental groups after 24 h was significant. PBM with 940 nm, 0.1 W, 4 J, 21.05 J/cm2, and 40 s per tooth is not able to produce statistically significant changes in the concentration of IL-6 in GCF, immediately or after 24 h of its application, during initial orthodontic treatment with light forces.