Effect of Blue-Light-Emitting Diode Exposure on Collagen Density of Periodontal Ligament During Orthodontic Tooth Movement in Rats

Abstract

Photobiomodulation therapy using Light Emitting Diode (LED) with a certain period and intensity can stimulate tissue repair and accelerate orthodontic tooth movement. During remodeling, collagen on periodontal ligaments was formed on the pressure and tension sides. The aim of this study was to investigate the effect of exposure time and observation day of blue LED on the collagen density of periodontal ligament of the pressure and tension sides of Wistar rats. Forty-eight male Wistar rats aged 3-4 months weighing 300-500 grams were divided into four groups: the control group; the group exposed to LED with λ1000 nm of 490 mW/cm2 for 25, 30, and 35 seconds once a day. In addition, their mandibular inter-incisor was administered with thirty-five grams orthodontic force using an open coil spring. The calculations on the collagen density of pressure and tension sides were carried out on days 0, 3, 7, and 14 using the TinEye application. Statistical analysis test was conducted using two-way ANOVA and LSD post hoc test. The results showed a more significant increase in the collagen density of the pressure and tension sides than that of the control group (p <0.05). The collagen density of pressure and tension sides reach the highest point at 30 seconds exposure followed by 35 and 25 seconds. The collagen density of pressure sides decreased on the 3rd day and increased afterward, and the tension sides continued to increase on the 3rd day afterward. The study showed that blue light LEDs were able to increase collagen density on the pressure and tension sides, with optimal exposure at 30 seconds, and it reached the highest point at day 14.