Photobiostimulation activity of different low-level laser dosage on masticatory muscles and temporomandibular joint in an induced arthritis rat model.

This study aimed to investigate the anti-inflammatory effects of different dosage of low-level laser therapy (LLLT) in an experimental model of temporomandibular joint (TMJ) arthritis. One hundred male Wistar rats were used and divided into the following groups: CG, control group; AG, animals group with left TMJ arthritis induced by intra-articular injection of Complete Freund's adjuvant - CFA; LG5, LG10 and LG20 - animals with arthritis and treated with LLLT at doses 5, 10, and 20 J/cm2, respectively. Morphological analysis was performed by TMJ histological sections stained with hematoxylin-eosin (HE), picrosirius (PSR), and toluidine blue (TB), as well as histomorphometric evaluation of cartilage, articular disc, and masticatory muscles. The amount of feed consumed within 3 weeks was evaluated, and biochemical analysis of TMJ tissues included measurement of sulfated glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) 2 and 9 zymography, and ELISA for cytokines IL-6, TNF-α, and IL-1ß. Only the 20 J/cm2 dose promoted higher feed intake compared to AG. On the other hand, all LLLT doses promoted better organization of articular disc collagen fibers, greater number of proteoglycans in articular cartilage, increased area and diameter of left lateral pterygoid fibers, reduced latent and active MMP 9 and 2 activity, and lower IL-1ß concentration compared to AG. Considering the study limitations, it was observed that LLLT treatments were effective in protecting and tissue cleansing joint structures, accelerating tissue repair, especially at lower doses.

Photobiomodulation versus light-emitting diode (LED) therapy in the treatment of temporomandibular disorder: study protocol for a randomized, controlled clinical trial.

BACKGROUND: Temporomandibular disorder (TMD) is described as a subgroup of orofacial pain with a set of signs and symptoms that involve the temporomandibular joint, masticatory muscles, ears, and neck. TMD can occur unilaterally or bilaterally and approximately 70% of the population is affected with at least one sign. The disorder progresses with orofacial pain, muscle pain involving the masticatory and cervical muscles, joint noises (clicks and pops), joint block, mandibular dysfunction, and headache. The etiology can be abnormal occlusion and/or posture, trauma involving local tissues, repetitive microtrauma, parafunctional habits, and an increase in emotional stress. Studies have demonstrated that phototherapy is an efficient option for the treatment of TMD, leading to improvements in pain and orofacial function. METHODS: The aim of the proposed study is to compare the effects of two sources of photobiomodulation in individuals with TMD. A randomized, controlled, double-blind, clinical trial is proposed, which will involve 80 individuals aged 18-65 years allocated to either a laser group or light-emitting diode (LED) group submitted to 12 sessions of phototherapy. The Research Diagnostic Criteria for TMDs will be used to evaluate all participants. Pain will be measured using the visual analog scale and maximum vertical mandibular movement will be determined with the aid of digital calipers. DISCUSSION: This study compares the effects of two modalities of laser therapy on the pain and orofacial function of patients with TMD dysfunction. Photobiomodulation and LED therapy are treatment options for reducing the inflammatory process and pain as well as inducing the regeneration of the target tissue. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03257748 . Registered on 8 August 2017.

Evaluation of low-level laser therapy effectiveness on the pain and masticatory performance of patients with myofascial pain.

This study investigated the effect of low-level laser therapy (LLLT) on the masticatory performance (MP), pressure pain threshold (PPT), and pain intensity in patients with myofascial pain. Twenty-one subjects, with myofascial pain according to Research Diagnostic Criteria/temporomandibular dysfunction, were divided into laser group (n = 12) and placebo group (n = 9) to receive laser therapy (active or placebo) two times per week for 4 weeks. The measured variables were: (1) MP by analysis of the geometric mean diameter (GMD) of the chewed particles using Optocal test material, (2) PPT by a pressure algometer, and (3) pain intensity by the visual analog scale (VAS). Measurements of MP and PPT were obtained at three time points: baseline, at the end of treatment with low-level laser and 30 days after (follow-up). VAS was measured at the same times as above and weekly throughout the laser therapy. The Friedman test was used at a significance level of 5% for data analysis. The study was approved by the Ethics Committee of the Federal University of Sergipe (CAAE: 0025.0.107.000-10). A reduction in the GMD of crushed particles (p < 0.01) and an increase in PPT (p < 0.05) were seen only in the laser group when comparing the baseline and end-of-treatment values. Both groups showed a decrease in pain intensity at the end of treatment. LLLT promoted an improvement in MP and PPT of the masticatory muscles.

Effect of low-level laser therapy on the post-surgical inflammatory process after third molar removal: study protocol for a double-blind randomized controlled trial.

BACKGROUND: Low-level laser therapy (LLLT) has been shown to modulate the inflammatory process without adverse effects , by reducing pain and swelling and promoting the repair of damaged tissues. Because pain, swelling and muscle spasm are complications found in virtually all patients following oral surgery for the removal of impacted teeth, this model has been widely used to evaluate the effects of LLLT on the inflammatory process involving bone and, connective tissue and the muscles involved in mastication. METHODS/DESIGN: After meeting the eligibility criteria, 60 patients treated at a Specialty Dental Center for the removal of impacted lower third molars will be randomly divided into five groups according to the type of laser therapy used at the end of surgery (intraoral irradiation with 660 nm laser; extraoral irradiation with 660 nm laser; intraoral irradiation with 808 nm laser; extraoral irradiation with 808 nm laser and no irradiation). To ensure that patients are blinded to the type of treatment they are receiving, the hand piece of the laser apparatus will be applied both intraorally and extraorally to all participants, but the device will be turned on only at the appropriate time, as determined by the randomization process. At 2 and 7 days after surgery, the patients will be evaluated by three blinded evaluators who will measure of swelling, mouth opening (muscle spasm evaluation) and pain (using two different pain scales). The 14-item Oral Health Impact Profile (OHIP-14) will be used to assess QOL. All data will be analyzed with respect to the normality of distribution using the Shapiro-Wilk test. Statistically significant differences between the experimental groups will be determined using analysis of variance, followed by a suitable post hoc test, when necessary. The significance level will be set at α = 0.05. DISCUSSION: The lack of standardization in studies with regard to the samples, methods and LLLT parameters complicates the determination of the actual effect of laser therapy on this model. The present study aims to provide a randomized, controlled, double-blind trial to compare four different LLLT parameters in relation to the outcomes of pain, swelling and muscle spasm following surgery for the extraction of impacted third molars and evaluate the effects os surgery on patients' quality os life (QOL). TRIAL REGISTRATION: Brazilian Registry of Clinical Trials - Rebec (RBR-6XSB5H).

Avaliação da abertura bucal em pacientessubmetidos à radioterapia de cabeça e pescoço / Evaluation of mouth opening in patients undergoing head and neck radiotherapy

A radioterapia de cabeça e pescoço quando direcionada à articulaçãotemporomandibular e músculos da mastigação, pode provocar sequelas como redução daamplitude de abertura bucal e trismo, que, muitas vezes, pode ser irreversível.Objetivo: comparar a amplitude de abertura bucal, antes e após a radioterapia da regiãode cabeça e pescoço.Metodologia: foram selecionados 30 pacientes com diagnóstico de tumores malignos decabeça e pescoço para serem submetidos à mensuração da abertura bucal 30 dias antes daradioterapia, e 90 dias após. Também foram observadas as características gerais comotipo histológico do tumor e dose de radioterapia.Resultados: a idade média da amostra foi de 58 anos, sendo que 80,76% eram do sexomasculino e 19,24% do feminino. Na primeira avaliação encontrou‐se limitação deabertura bucal (35,08±8,74), e 90 dias após a radioterapia houve aumento da limitação deabertura bucal (31,5±10,42), porém, sem mostrar significância estatística (p≤0,061).Conclusão: não houve agravamento da limitação de abertura bucal após três meses deradioterapia...

When temporomandibular joint and muscles of mastication are in the fieldof radiation, trismus and restriction of mouth opening are common and often irreversiblesequelae.Aim: compare mouth opening before and after head and neck radiotherapy.Methodology: thirty patients with head and neck malignant tumors were chosen to havetheir mouth opening measured 30 days before and 90 days after radiotherapy. Generalcharacteristics as histological type of the tumor and radiotherapy dose were alsoevaluated.Results: the mean age of the sample was 58 years, 21 subjects (80.76%) were male, and 5(19.24%) were female. At the first evaluation, we found mouth opening restriction(35.08±8.74) and ninety days after radiotherapy the mouth opening increased (31.5±10.42),but without statistical significance (p≤0.061).Conclusion: the mouth opening did not worse after 3 months of radiotherapy...

A mobilization regimen to prevent mandibular hypomobility in irradiated patients: an analysis and comparison of two techniques.

Radiotherapy, when used in head and neck cancer treatment, can produce side effects in the patients, such as decreased salivary production, xerostomia, opportunistic infections, radiation caries, dysphagia, local discomfort and the limitation of mouth opening. The aim of this study was to evaluate the amplitude of mouth opening in patients before and immediately after the completion of radiotherapy, comparing the effectiveness of two physiotherapy exercises. The irradiated sites included the masticatory muscles. The results demonstrated that there were no statistically significant differences between the two instituted exercises; however there was a trend towards better clinical results in group 2. The amplitude of mouth opening showed a trend towards reduction, but this was not statistically significant. When the pterygoid and sternocleidomatoid muscles were included in the irriated field, patients were observed to have more morbidity. This indicates the great importance of these muscles in mouth opening. Based on the results obtained within this study, it is not possible to conclude that physiotherapy exercies are efficacious in preventing trismus. Future longitudinal studies are required to verify the onset of trismus in radiotherapy patients.

[Laser therapy in temporomandibular dysfunction (soft laser application points)]. / Laserterapia en las disfunciones témporo-mandibulares (puntos de aplicación del láser blando).

It is work out and discuss one of the principal problems in the laser therapy use during the TMJ dysfunction treatment: the determination of the application points for the soft-laser stay, detailing the position of some of them that are essentials to obtain the objectives of this type of treatment.