The use of laser photobiomodulation as pre-anesthetic tissue management technique in reducing injection pain in children.

BACKGROUND: One of the main goals for pediatric dentists is to offer a painless anesthesia experience. Laser photobiomodulation is among the suggested strategies to decrease injection pain. So, this study aimed to assess the impact of laser photobiomodulation on local anesthesia (LA) injection pain in children and its effect on the efficacy of LA during pulpotomy and SSC procedures. METHODS: The research was carried out as a randomized controlled clinical trial with two parallel group design. It involved 64 cooperative healthy children, age range from 5 to 7 years, each having at least one maxillary molar indicated for pulpotomy. Children were randomly allocated to one of the two groups based on the pre-anesthetic tissue management technique used: test group received laser photobiomodulation, while control group received topical anesthetic gel. Pain during injection, pulpotomy, and SSC procedures was assessed using physiological measures (Heart Rate (HR)), subjective evaluation (modified Face-Pain-Scale (FPS), and objective analysis (Sound-Eye-Motor scale (SEM)). RESULTS: A total of 64 children with mean age 6.23 ± 0.78 participated in this research. The mean HR scores were significantly lower in the laser PBM group during buccal and palatal infiltration injections. The SEM mean scores were significantly lower in the laser PBM group during both injections. For the FPS scale, the number of children who recorded satisfaction during injection was significantly higher in laser PBM group. There was no statistically significant difference in mean HR as well as in SEM and FPS scores between the two groups during pulpotomy and SSC procedures. Comparisons between the two study groups were performed using independent samples t- and Mann-Whitney U tests. Significance was set at p value < 0.05. CONCLUSION: Laser photobiomodulation is a promising non-pharmacological pre-anesthetic tissue management technique in children that offered less painful injection compared to topical anesthetic gel without compromising the effectiveness of LA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05861154. Registered on 16/5/2023.

Efficacy of photobiomodulation in the treatment of avulsed teeth: A systematic review of animal studies.

The objective of this systematic review was to evaluate the effectiveness of photobiomodulation therapy (PBM) in managing avulsed teeth. This systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (i.e., "PRISMA") statement 2020 and was registered in the International Prospective Register of Systematic Reviews (i.e., PROSPERO) with number CRD42022362198. The participants, intervention, comparison, outcomes, and study design (i.e., PICOS) for the present study considered the following question: "Does the use of laser PBM in the treatment of teeth with avulsion influence tissue repair performance?" A literature search was performed in PubMed/MEDLINE, Embase, Web of Science, Cochrane Library, and ProQuest databases until January 2023. The SYRCLE's RoB tool (Systematic Review Center for Laboratory Animal Experimentation) for animal studies were used for quality assessment. A total of 7 in vivo studies published between 2011 and 2018 were included in this systematic review for qualitative analysis. All studies used Wistar rats, totaling 368 specimens that simulated tooth avulsion trauma. The effect of photodynamic therapy in the treatment of avulsed teeth was positive in 5 studies (significant increase in tissue repair) and negative in 2 studies, in which both studies with negative results kept teeth in saline solution before reimplantation and showed the longest time and power of laser application. PBM appears to be effective for tissue repair in the treatment of avulsed teeth, depending on the means of conservation of the avulsed tooth and the laser application protocol.

Three-dimensional irradiance and temperature distributions resulting from transdermal application of laser light to human knee-A numerical approach.

The use of light for therapeutic applications requires light-absorption by cellular chromophores at the target tissues and the subsequent photobiomodulation (PBM) of cellular biochemical processes. For transdermal deep tissue light therapy (tDTLT) to be clinically effective, a sufficiently large number of photons must reach and be absorbed at the targeted deep tissue sites. Thus, delivering safe and effective tDTLT requires understanding the physics of light propagation in tissue. This study simulates laser light propagation in an anatomically accurate human knee model to assess the light transmittance and light absorption-driven thermal changes for eight commonly used laser therapy wavelengths (600-1200 nm) at multiple skin-applied irradiances (W cm-2 ) with continuous wave (CW) exposures. It shows that of the simulated parameters, 2.38 W cm-2 (30 W, 20 mm beam radius) of 1064 nm light generated the least tissue heating -4°C at skin surface, after 30 s of CW irradiation, and the highest overall transmission-approximately 3%, to the innermost muscle tissue.

Treatment of Vascular Parkinsonism: A Systematic Review.

BACKGROUND AND AIMS: Although the distinction between vascular parkinsonism (VP) and idiopathic Parkinson's disease (IPD) is widely described, it is not uncommon to find parkinsonisms with overlapping clinical and neuroimaging features even in response to levodopa treatment. In addition, several treatments have been described as possible adjuvants in VP. This study aims to update and analyze the different treatments and their efficacy in VP. METHODS: A literature search was performed in PubMed, Scopus and Web of Science for studies published in the last 15 years until April 2022. A systematic review was performed. No meta-analysis was performed as no new studies on response to levodopa in VP were found since the last systematic review and meta-analysis in 2017, and insufficient studies on other treatments were located to conduct it in another treatment subgroup. RESULTS: Databases and other sources yielded 59 publications after eliminating duplicates, and a total of 12 original studies were finally included in the systematic review. The treatments evaluated included levodopa, vitamin D, repetitive transcranial magnetic stimulation (rTMS) and intracerebral transcatheter laser photobiomodulation therapy (PBMT). The response to levodopa was lower in patients with VP with respect to IPD. Despite this, there has been described a subgroup of patients with good response, it being possible to identify them by means of neuroimaging techniques and the olfactory identification test. Other therapies showed encouraging results in studies with some risk of bias. CONCLUSIONS: The response of VP to different therapeutic strategies is modest. However, there is evidence that a subgroup of patients can be identified as more responsive to L-dopa based on clinical and neuroimaging criteria. This subgroup should be treated with L-dopa at appropriate doses. New therapies such as vitamin D, rTMS and PBMT warrant further studies to demonstrate their efficacy.

Wound contraction rate in excised and unexcised burn wounds with laser photobiomodulation: Systematic review and meta-analysis of preclinical studies.

INTRODUCTION: Laser photobiomodulation (laser PBM) is an effective means of accelerating burn wound contraction, however it is still unclear whether laser PBM produces greater benefit when applied directly to excised and unexcised burn wounds . The aim of this systematic review of preclinical studies was to determine the effectiveness of laser PBM in the wound contraction rate in excised and unexcised burn wounds. MATERIALS AND METHODS: A systematic search was conducted in the EMBASE, MEDLINE and LILACS databases. Preclinical studies were included that analysed the effectiveness of laser PBM in burn wound contraction, and assessed wound closure. The SYRCLE risk of bias tool was used. Random effects models were used to estimate the pooled effect. RESULTS: Thirteen studies were included in the qualitative analysis and six in the quantitative analysis. Two weeks after the lesion, laser PBM favoured the wound contraction percentage, increasing the closure rate in excised burn wounds (SMD= 1.34, CI 95% 0.41 to 2.27, 0.41-2.27, I2=0%, =0%, low certainty of evidence. In unexcised burns, it was uncertain whether laser PBM increased or diminished the wound contraction rate (SMD=1.22(SMD=1.22 CI 95% -0.05 to 2.49, I2=68%; =68%; very low certainty of evidence). CONCLUSIONS: In the animal model, laser PBM is effective in increasing the wound contraction rate in excised burns. However, due to the low certainty of the evidence, uncertainty remains about the true magnitude of the effect of laser on wound contraction in animals; our results should therefore be interpreted with caution.

Effects of laser photobiomodulation on tgf-ß and vegf expression in burn wound: systematic review and meta-analysis in the animal model / Influencia de la fotobiomodulación por láser en la expresión de tgf-ß y vegf en heridas por quemadura: revisión sistemática y meta-análisis en modelo animal

SUMMARY: Laser photobiomodulation (laser PBM) is known to be able to accelerate burn wound healing in the animal model; however little evidence exists on the action of laser PBM on the expression of important proteins in wound healing in the animal model, such as VEGF and TGF-ß1. The aim of this study was to carry out a systematic review in order to analyse the effect of laser PBM on VEGF and TGF-ß expression during burn wound repair in the animal model. A systematic review was carried out of the EMBASE, PubMed/ MEDLINE and LILACS databases. The studies included were preclinical studies that analysed the action of laser PBM on the expression of VEGF and TGF-ß (1, 2, 3) during burn wound repair in the animal model. The SYRCLE risk of bias tool was used. Random effect models were used to estimate the combined effect. Increased VEGF expression was observed with the use of laser PBM at 4.93 J/cm2 per point in the first two weeks after induction of the burn wound, with greater size of effect in the second week (SDM = 5.72; 95% CI: 3.14 to 8.31, I2 = 0 %; very low certainty of evidence). We also observed that the effect of laser PBM on TGF-ß1 expression was greater than in the control in the first week (SDM = -0.45; 95% CI: -1.91 to 1.02, I2 = 51 %; very low certainty of evidence), but diminished in the third week after induction of the lesion (SDM = -2.50; 95% CI: 3.98 to -1.01, I2 = 0 %; very low certainty of evidence). Laser PBM has an effect on TGF-ß1 and VEGF expression, promoting burn wound repair in the animal model.

RESUMEN: Es sabido que la fotobiomodulación por láser (FBM láser) puede acelerar el proceso de curación de heridas por quemadura en modelo animal, sin embargo aún se carece de mayor evidencia sobre la acción de la FBM láser en la expresión de proteínas importantes en el proceso de curación de heridas en modelo animal, como VEGF y TGF-ß1. Así, el objetivo de este estudio fue realizar una revisión sistemática a fin de analizar el efecto de la FBM láser sobre la expresión de VEGF, TGF-ß durante el proceso de reparación de heridas por quemadura en modelo animal. Se realizó una búsqueda sistemática en las bases de datos EMBASE, PubMed/MEDLINE y LILACS. Se incluyeron estudios preclínicos que analizaron la acción de la FBM láser en la expresión de VEGF, TGF-ß (1, 2, 3) durante el proceso de reparación de heridas por quemadura en modelo animal. Se utilizó la herramienta de riesgo de sesgo SYRCLE. Se utilizaron modelos de efectos aleatorios para estimar el efecto combinado. Observamos aumento de la expresión de VEGF con el uso de FBM láser 4.93 J/cm2 por punto, en las dos primeras semanas tras inducción de la herida por quemadura, con mayor tamaño de efecto en la segunda semana (SDM = 5,72; IC del 95%: 3,14 a 8,31, I2 = 0 %; certeza de la evidencia muy baja). También se observó el efecto de la FBM láser en la expresión del TGF- ß1 que fue mayor que el control en la primera semana (SDM = - 0,45; IC del 95%: -1,91 a 1,02, I2 = 51 %; certeza de la evidencia muy baja), disminuyendo en la tercera semana tras inducción de la lesión (SDM = -2,50; IC del 95%: -3,98 a -1,01; I2 = 0 %; certeza de la evidencia baja). La TFB por láser ejerce influencia en la expresión de TGF-ß1 y VEGF favoreciendo el proceso de reparación de heridas por quemadura en modelo animal.

Laser-photobiomodulation on experimental cancer pain model in Walker Tumor-256.

CONTEXT: Cancer Pain is considered a common and significant clinical problem in malignant neoplasms, comprising 20% to 50% of all patients with tumor progression. Laser photobiomodulation (L-PBM) has been used in a multitude of pain events, ranging from acute trauma to chronic articular. However, L-PBM has never been tested in cancer pain. OBJECTIVES: Evaluate hyperalgesia, edema, COX-1, COX-2, IL-10, and Bdkrb1 mRNA in low-level laser irradiated Walker-256 tumor-bearing rats. METHODS: Rat hind paw injected with Walker Tumor-256 (W-256) and divided into six groups of 6 rats: G1 (control) - W-256 injected, G2- W-256 + Nimesulide, G3- W-256 + 1 J, G4- W-256 + 3 Jand G5- W256 + 6 J. Laser parameters: λ = 660 nm, 3.57 W/cm2, Ø = 0.028 cm2. Mechanical hyperalgesia was evaluated by Randall-Selitto test. Plethysmography measured edema; mRNA levels of COX-1, COX-2, IL-10, and Bdkrb1were analyzed. RESULTS: It was found that the W-256 + 1 J group showed a decrease in paw edema, a significant reduction in pain threshold. Higher levels of IL-10 and lower levels of COX-2 and Bdkrb1 were observed. CONCLUSION: Results suggest that 1 J L-PBM reduced the expression of COX-2 and Bdkrb1 and increasing IL-10 gene expression, promoting analgesia to close levels to nimesulide.

Laser photobiomodulation for cartilage defect in animal models of knee osteoarthritis: a systematic review and meta-analysis.

To review and assess the efficacy of laser photobiomodulation for cartilage defect in animal models of knee osteoarthritis (KOA). Medline, Web of Science, and EMBASE were searched. Studies were considered if the global quality score of cartilage were parallelly reported between laser and untreated control groups. The methodological quality of each study was assessed using a modified 10-item checklist. The effect size was estimated by standardized mean difference (SMD) and pooled based on the random-effects model. Stratified analysis and regression analysis were conducted to partition potential heterogeneity. An adjusted significant level of 0.01 was acceptable. Five hundred eight initial search recordings were identified, of which 14 studies (including 274 animals) were included for quantitative analysis. The global quality scores mostly weighted by the structural integrity and chondrocyte distribution were measured by different four scales including Histologic Histochemical Grading System (HHGS), Osteoarthritis Research Society International (OARSI), Pineda, and Huang. There were considerable variances on laser parameters and irradiation time among those included studies. Overall, a moderate level of methodological qualities was determined. The synthesis results indicated that the SMD effect size was significantly larger in HHGS (z = 2.61, P = 0.01) and Huang (z = 4.90, P < 0.01) groups. Stratified by irradiance, SMD of low (< 1 W/cm2) but not high (≥ 1 W/cm2) level estimated significant difference (z = 5.62, P < 0.01). Meta-regression identified a significant association for SMDs and irradiation time (P < 0.01). Yet, Egger's test detected small study effect (P < 0.01). No individual study with significant variance was found in homogeneity tests. The results demonstrated the positive effect of laser photobiomodulation for cartilage defect in animal models of KOA under proper irradiance and adequate irradiation time.

Gene Expression Analysis of Chondrogenic Markers in Hair Follicle Dermal Papillae Cells Under the Effect of Laser Photobiomodulation and the Synovial Fluid.

Introduction: Regarding the limited ability of the damaged cartilage cells to self-renew, which is due to their specific tissue structure, subtle damages can usually cause diseases such as osteoarthritis. In this work, using laser photobiomodulation and an interesting source of growth factors cocktail called the synovial fluid, we analyzed the chondrogenic marker genes in treated hair follicle dermal papilla cells as an accessible source of cells with relatively high differentiation potential. Methods: Dermal papilla cells were isolated from rat whisker hair follicle (Rattus norvegicus) and established cell cultures were treated with a laser (gallium aluminum arsenide diode Laser (λ=780 nm, 30 mW) at 5 J/cm2 ), the synovial fluid, and a combination of both. After 1, 4, 7, and 14 days, the morphological changes were evaluated and the expression levels of four chondrocyte marker genes (Col2a1, Sox-9, Col10a1, and Runx-2) were assessed by the quantitative real-time polymerase chain reaction. Results: It was monitored that treating cells with laser irradiation can accelerate the rate of proliferation of cells. The morphology of the cells treated with the synovial fluid altered considerably as in the fourth day they surprisingly looked like cultured articular chondrocytes. The gene expression analysis showed that all genes were up-regulated until the day 14 following the treatments although not equally in all the cell groups. Moreover, the cell groups treated with both irradiation and the synovial fluid had a significantly augmented expression in gene markers. Conclusion: Based on the gene expression levels and the morphological changes, we concluded that the synovial fluid can have the potential to make the dermal papilla cells to most likely mimic the chondrogenic and/or osteogenic differentiation, although this process seems to be augmented by the irradiation of the low-level laser.

Laser photobiomodulation is more effective than ultrasound therapy in patients with chronic nonspecific low back pain: a comparative study.

The purpose of this study was to compare the effects of laser photobiomodulation therapy (lPBMt) and ultrasound therapy (UST) in patients with chronic non-specific low back pain (CNLBP). Forty-five patients with CNLBP aged 30-40 years were divided randomly into three groups of 15 subjects each. The lPBMt group received 8 weeks of lPBMt with an exercise program, while the UST group received 8 weeks of UST with the same exercise program; the control group received only the exercise program for 8 weeks. Pain, disability, functional performance, and lumbar range of motion were assessed at the beginning of the study and after 8 weeks. There were no significant differences in demographic and clinical characteristics among the three groups at baseline (p > 0.05). At the end of the study, there were significant improvements in pain, disability, and functional performance in the two experimental groups (p < 0.05), but changes in the control group were non-significant. However, lumbar range of motion was significantly improved only in the lPBMt group (p < 0.05). When the three groups were compared in terms of a change in clinical variables, there was a significant difference among the three groups in all measures in favor of lPBMt group. Based on our results, both lPBMt or UST combined with an 8-week exercise program seemed to be effective methods for decreasing pain, reducing disability, and increasing functional performance in patients with CNLBP, although lPBMt is more effective than UST.

Comparison of two different laser photobiomodulation protocols on the viability of random skin flap in rats.

To identify the best low level laser photobiomodulation application site at the same irradiation time to increase the viability of the skin flap in rats. Eighteen male rats (Rattus norvegicus: var. Albinus, Rodentia Mammalia) were randomly distributed into three groups (n = 6). Group I (GI) was submitted to simulated laser photobiomodulation; group II (GII) was submitted to laser photobiomodulation at three points in the flap cranial base, and group III (GIII) was submitted to laser photobiomodulation at 12 points distributed along the flap. All groups were irradiated with an Indium, Galium, Aluminum, and Phosphorus diode laser (InGaAlP), 660 nm, with 50 mW power, irradiated for a total time of 240 s in continuous emission mode. The treatment started immediately after performing the cranial base random skin flap (10 × 4 cm2 dimension) and reapplied every 24 h, with a total of five applications. The animals were euthanized after the evaluation of the percentage of necrosis area, and the material was collected for histological analysis on the seventh postoperative day. GII animals presented a statistically significant decrease for the necrosis area when compared to the other groups, and a statistically significant increase in the quantification of collagen when compared to the control. We did not observe a statistical difference between the TGFß and FGF expression in the different groups evaluated. The application of laser photobiomodulation at three points of the flap cranial base was more effective than at 12 points regarding the reduction of necrosis area.

Photobiomodulation Therapy in Veterinary Medicine: A Review.

Laser therapy, or photobiomodulation, has rapidly grown in popularity in human and veterinary medicine. With a number of proposed indications and broad, sometimes anecdotal, use in practice, research interest has expanded aimed at providing scientific support. Recent studies have shown that laser therapy alters the inflammatory and immune response as well as promotes healing for a variety of tissue types. This review will cover the history of the modality, basic principles, proposed mechanisms of action, evidence-based clinical indications, and will guide the practitioner through its application in practice.

Sperm motility is enhanced by Low Level Laser and Light Emitting Diode photobiomodulation with a dose-dependent response and differential effects in fresh and frozen samples.

BACKGROUND: The effects of Low Level Light Therapy (LLLT) on cellular function arise predominantly from stimulation of ATP production and reduction of oxidative stress. These effects are dose dependent and a function of beam irradiance and irradiation time. Human sperm motility has been shown to increase with LLLT irradiation. The objective of this study was to investigate the effects of laser and Light Emitting Diode (LED) LLLT photobiomodulation on human spermatozoa motility and DNA integrity. METHODS: An in-vitro controlled trial was performed within an IVF clinic laboratory using three human semen specimens, one fresh and two frozen. Sperm were exposed to light from a GaAlAs single laser (810 nm 200 mW) and an LED cluster (660 nm and 850 nm total power 2 W) for various irradiation times. Sperm motility for the test and control aliquots was assessed using a SQA-IIB analyser, but fertilizing ability was not. Sperm chromatin integrity was tested using the Sperm Chromatin Structure Assay. RESULTS: The Sperm Motility Index and Total Functional Sperm Count increased up to four fold compared to controls with inhibitory effects observed at higher doses (longer irradiation times). The maximum effect varied with irradiance and irradiation time and whether the sample was fresh or frozen. DISCUSSION: Human sperm motility is modified by exposure to LLLT and this motility modification is dependent upon beam irradiance and irradiation time as well as the condition of the sample. A higher stimulatory dose provides a rapid increase in motility that is short in duration, while a lower stimulatory dose provides a slower increase in motility. An inhibitory does causes reduced motility. Future research could consider animal models, such as the mouse, to test fertilization capacity and the safety of resulting fetuses.

Evaluation of bone repair after application of a norbixin membrane scaffold with and without laser photobiomodulation (λ 780 nm).

Biocompatible membranes are widely used in medicine to stimulate bone repair. Several studies have demonstrated that laser photobiomodulation (PBM) also stimulates osteoblast proliferation and osteogenesis at the fracture site, leading to a greater deposition of bone mass and accelerating the process of bone consolidation. This work assessed the therapeutic effect of 780-nm laser PBM and a polystyrene membrane coated with norbixin and collagen (PSNC) on bone healing in rats with calvarial bone defect. Histological staining, Raman spectroscopy, and scanning electron microscopy (SEM) were used to evaluate the bone repair process. Four experimental treatment groups were compared: C, control; M, membrane only; L, laser PBM only; and ML, membrane + laser PBM. A bone defect was created in the calvaria of each animal, with each group subdivided into two subgroups that underwent euthanasia after 15 and 30 days treatment. The L and ML groups were irradiated (λ = 780 nm, ED = 6 J/cm2, P = 60 mW, t = 4 s) postoperatively on alternate days until they were euthanized. The bone concentration of hydroxyapatite (CHA) showed a clear gradation with increasing phosphate area in the order B (normal cortical bone) > L > M > ML > C for both periods. The PSNC membrane was effective in reducing the inflammatory process and served as a scaffold for bone repair. The laser PBM also showed positive effects on the bone repair process with increased deposition and organization of the newly formed bone. However, laser PBM failed to improve the bioactive properties of the membrane scaffold.

Analysis of Aloe vera cytotoxicity and genotoxicity associated with endodontic medication and laser photobiomodulation.

This study aims to evaluate, in vitro, the effect of Aloe vera associated with endodontic medication, with or without laser photobiomodulation (FTL) irradiation in FP6 human pulp fibroblasts. The materials were divided into eight groups: CTR - control; CL - FTL alone; AA - Aloe vera with distilled water; AL - Aloe vera with distilled water and FTL; HA - calcium hydroxide P.A. with distilled water; HL - calcium hydroxide P.A. with distilled water and FTL; HAA - calcium hydroxide P.A. with Aloe vera and distilled water; HAL - calcium hydroxide P.A. with Aloe vera, distilled water, and FTL. The cytotoxicity was evaluated by MTT assay at 24, 48, and 72h and the genotoxicity by micronucleus test assay. This study was performed in triplicate. Data obtained in both tests were statistically analyzed by ANOVA and Tukey's tests (p≤0.05). Group AA presented high genotoxicity and low cytotoxicity. After 24, 48, and 72h, the group HAA significantly reduced the cell viability. Interaction with FTL showed slightly increase cell viability after 24 and 48h in groups CL and HL (p<0.001), despite the high genotoxicity in group CL and low genotoxicity in group HL. Group AL showed higher cell survival rate at 72h (p<0.05) and high genotoxicity (p<0.001). It was concluded that Aloe vera allowed higher cell viability in human pulp fibroblasts in the presence of calcium hydroxide or with FTL separately, but genotoxicity increased in these associations.

Análise clínica do efeito da fotobiomodulação laser (GaAs - 904 nm) sobre a disfunção temporomandibular / Clinical analysis of the effect of laser photobiomodulation (GaAs - 904 nm) on temporomandibular joint dysfunction

INTRODUÇÃO: Nos últimos anos, tem sido notado grande interesse no estudo de novas modalidades para o tratamento das disfunções temporomandibulares (DTM). A dor descrita como dor facial, cefaléia ou dor de ouvido, comumente exacerbada pela função da mandíbula, é, em geral, a principal queixa do paciente. A fotobiomodulação laser vem sendo utilizada no tratamento da dor em DTM. OBJETIVO: O objetivo deste estudo foi verificar o nível de dor de pacientes com DTM tratados com fotobiomodulação laser. MATERIAIS E MÉTODOS: Foram estudados 18 pacientes do sexo feminino, com idade média de 27 anos (± 7), com diagnóstico de DTM, os quais foram separados aleatoriamente em dois grupos: Placebo (Controle) e Tratado. O Grupo Tratado (n= 10) recebeu atendimento duas vezes por semana, por quatro semanas consecutivas (totalizando oito aplicações). Utilizou-se o laser de GaAs (904 nm), 6 J/cm², 0,38 mW/cm², área do feixe de 0,039 cm², com modo de emissão contínua. Realizou-se a aplicação do laser em quatro pontos pré-auriculares e um em meato acústico externo. O Grupo Placebo (n= 8) foi manipulado como o tratado, porém com o laser desligado. Para análise do nível de dor dos pacientes, empregou-se a Escala Visual Analógica (EVA) de dor, antes e após a terapia. Para a análise dos dados, empregou-se o teste t de Student, com nível de significância de 5 por cento (p< 0,05). RESULTADOS: Observou-se redução significativa (p< 0,05) do nível de dor do Grupo Tratado. CONCLUSÕES: A fotobiomodulação laser (GaAs, 904 nm) testada demonstrou ser positiva para o alívio da sintomatologia dolorosa em pacientes com DTM.

INTRODUCTION: Over the last few years, there has been great interest in studying new methods for treating temporomandibular joint dysfunction (TMD). Pain, described as facial pain, headache or earache, usually exacerbated by jaw use, is generally the patients' main complaint. Laser photobiomodulation has been used for treating pain in cases of TMD. OBJECTIVE: The aim of this study was to investigate the pain levels in TMD patients treated with laser photobiomodulation. MATERIAL AND METHODS: Eighteen female patients of mean age was 27 years (± 7), with a diagnosis of TMD, were studied. They were randomly divided into two groups: Placebo (Control) and Experimental Groups. The Experimental Group (n= 10) received treatment twice a week, for four consecutive weeks (totaling eight applications). The GaAs laser (904 nm) was used, with 6 J/cm², 0.38 mW/cm², beam area of 0.039cm² and continuous emission mode. The laser was applied at four pre-auricular points and one in the external auditory meatus. The Placebo Group (n= 8) was manipulated in the same way as the treated group, but with the laser switched off. To analyze the patients' pain levels, a visual analog scale (VAS) was used, before and after the therapy. To analyze the data, Student's t test was used, with a significance level of 5 percent (p< 0.05). RESULTS: A significant reduction (p< 0.05) in the pain level was observed in the Treated Group. CONCLUSIONS: The tested laser photobiomodulation (GaAs, 904 nm) demonstrated positive results regarding the relief of painful symptoms in patients with TMD.