Assessment of different energy delivery settings in laser and LED phototherapies in the inflammatory process of rat’s TMJ induced by carrageenan

Abstract

Temporomandibular disorders (TMDs) are mostly inflammatory conditions widespread in the population. Previous studies have shown positive effects of either laser or light-emitting diode (LED) phototherapies on treating TMDs, but their action and mechanism in the inflammatory infiltrate of the temporomandibular joint are still poorly understood. The aim of this study was to assess, through histological analysis, the effectiveness of using laser light (λ 780 nm, 70 mW, continous wave (CW), 10 J) and LED (λ 850 ± 10 nm, 100 mW, CW, 10 J) on the inflammation of the temporomandibular joint of rats induced by carrageenan. Forty-five animals were divided into three groups with five animals each according to the experimental times of 2, 3, and 7 days: inflammation, inflammation+laser phototherapy, and inflammation+LED phototherapy. The first irradiation was performed 24 h after induction with an interval of 48 h between sessions. After animal death, specimens were processed and stained with hematoxylin-eosin (HE) and picrosirius. Then, the samples were examined histologically. Data were statistically analyzed. The inflammation group showed mild to moderate chronic inflammatory infiltrate between bone trabecules of the condyle. Over the time course of the study in the laser group, the region of the condyle presented mild chronic inflammation and intense vascularization. In the LED group, the condyle showed aspects of normality and absence of inflammation in some specimens. In all the time points, the laser-irradiated groups showed greater amount of collagen deposition in the condyle (p = 0.04) and in the disc (p = 0.03) when compared to the inflammation and LED groups, respectively. Laser- and LED-treated groups demonstrate a smaller number of layers of the synovial membrane when compared to the non-irradiated groups. It was concluded that, in general, laser and LED phototherapies resulted in a reduction of inflammatory infiltrate in the temporomandibular joint of rat.

Photobiomodulation with simultaneous use of red and infrared light emitting diodes in the treatment of temporomandibular disorder: study protocol for a randomized, controlled and double-blind clinical trial

“…The criteria of histological evaluation were the percentage of neutrophils and lymphocytes in relation to the total of cells in the observed area, and the percentage of blood vessels in relation to the observed area. [34] Prior to this, a study investigated the effects of phototherapy with the combination of different light sources on the nonspecific pain of a larger joint: the knee. The combination of 905 nm super-pulse laser and 875 and 640 nm LEDs were used, which proved effective in reducing pain and improving quality of life in patients with knee pain.…”

The Path to an Evidence-Based Treatment Protocol for Extraoral Photobiomodulation Therapy for the Prevention of Oral Mucositis

“…The highest peak is in the near infrared window at 812.0-846 nm. Additionally, PBMT in the near infrared window has shown efficacy for several other inflammatory/painful indications, such as osteoarthritis, colitis, and temporomandibular disorders [29][30][31][32][33][34][35][36]. Longer wavelengths beyond the near-infrared range lack evidence of efficacy [37].…”

Analysis of electric field and emission spectrum in the glow discharge of therapeutic plasma electrode

“…Panhoca et al [42] showed that low-level R-NIR photo-stimulation can be useful in improving outcomes related to pain relief and mandibular range of motion for TMD patients, while de Castro et al [43] reported reduction of inflammatory infiltrate in the TMJ. These effects could explain similar results reported by Do gan et al [25] for extra-oral application of plasma electrodes in direct contact with the skin in projection of the underlying TMJ.…”