Effectiveness of Photobiomodulation for Myofascial Pain in Temporomandibular Disorders

Photobiomodulation in the Management of Myofascial Pain: A Randomized and Blinded Clinical Trial

This randomized clinical trial aims to evaluate the effectiveness of photobiomodulation therapy (PBM) alone or combined with therapeutic exercises compared with placebo PBM associated with exercises in patients with myofascial temporomandibular disorders (TMD). Participants will be allocated into three groups: PBM alone, PBM combined with exercises, or placebo PBM combined with exercises. The intervention consists of 12 treatment sessions. Outcomes related to pain intensity, mandibular function, and clinical measures will be assessed over time. The study seeks to investigate whether PBM provides additional benefits in pain reduction and functional improvement in individuals with myofascial TMD.

Study Overview

• Status: Not yet recruiting
• Conditions: Pain Management; Myofacial Pain; Photobiomodulation; Temporomandibular Disorder (TMD)
• Intervention / Treatment: Device: Photobiomodulation Therapy; Behavioral: Therapeutic Exercises; Device: Sham Photobiomodulation Therapy

Detailed Description

This randomized, assessor-blinded, parallel-group clinical trial aims to evaluate the effects of photobiomodulation therapy (PBM) on clinical and psychosocial outcomes in adults with myofascial temporomandibular disorders (TMD). Myofascial pain is one of the most prevalent subtypes of TMD and is frequently associated with muscle tenderness, functional limitation, chronic pain, and psychological distress. Conservative and non-invasive therapies are considered first-line approaches, and PBM has emerged as a promising modality due to its potential anti-inflammatory and analgesic effects.

The primary objective of this study is to analyze the impact of PBM on muscle pain intensity, assessed using the Visual Analog Scale (VAS). Secondary objectives include evaluating specific muscle pain through DC/TMD clinical examination, chronic pain severity using the Graded Chronic Pain Scale version 2 (GCS v2), mandibular functional limitation using the Jaw Functional Limitation Scale (JFLS-20), quality of life assessed using the Patient Health Questionnaire (PHQ-9), and anxiety symptoms using the Generalized Anxiety Disorder scale (GAD-7).

A total of 120 adult undergraduate and graduate students from the Federal University of Rio Grande do Sul (UFRGS) will be recruited through institutional dissemination and interest forms. Eligible participants must be 18 years or older, diagnosed with myofascial TMD according to DC/TMD criteria, and able to attend all treatment sessions and follow-up assessments. Individuals with systemic musculoskeletal conditions, recent head and neck malignancy, previous temporomandibular joint surgery, pregnancy or lactation, severe psychiatric conditions that prevent participation, or ongoing treatments that may interfere with outcomes will be excluded.

Participants will undergo baseline assessment and will be randomly allocated (1:1:1) into three groups: (1) PBM alone; (2) PBM combined with therapeutic exercises; or (3) placebo PBM combined with therapeutic exercises. PBM will be delivered using a dual-wavelength diode laser device (810 + 980 nm) applied extraorally at standardized anatomical points over the temporomandibular joint and masticatory muscles. The intervention will consist of 12 treatment sessions performed three times per week over four weeks. Participants allocated to the exercise groups will perform daily home-based therapeutic exercises focused on muscle relaxation, joint mobility, and functional improvement, with adherence monitoring throughout the study.

Randomization will be performed by an independent investigator using a centralized allocation system with concealment procedures. Participants will remain blinded regarding active or placebo laser application, and outcome assessors and statisticians will remain blinded to group allocation to minimize performance and detection bias. Due to the nature of the interventions, the therapist delivering PBM will not be blinded.

Clinical and psychosocial outcomes will be assessed at baseline, after completion of the 12 treatment sessions, and at 1-month and 3-month follow-up visits. Adverse events and rescue medication use will be monitored throughout the study period. Data will be managed using Research Electronic Data Capture (REDCap®) and analyzed under the intention-to-treat principle using mixed-effects statistical models to evaluate changes over time and between groups.

The study aims to provide high-quality evidence regarding the effectiveness of PBM alone or combined with therapeutic exercises in reducing pain, improving mandibular function, and positively influencing psychological outcomes in individuals with myofascial TMD, contributing to evidence-based conservative management strategies.

• Study Type: Interventional
• Enrollment (Estimated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Manoela Domingues Martins, DDS, MSc, PhD; Phone Number: 5551 99608802; Email: manomartins@gmail.com
• Study Contact Backup: Name: Júlia Breda Soares, DDS, MSc; Phone Number: 5554 96077474; Email: julia.breda.soares@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Individuals with myofascial TMD (ICD-9 729.1; ICD-10 M79.1) diagnosed according to the DC/TMD criteria;
• Participants aged 18 years or older;
• Individuals able to communicate, read, write, and provide written informed consent in Portuguese.

Exclusion Criteria:

• Patients with a history of autoimmune connective tissue diseases, such as rheumatoid arthritis, psoriatic arthritis, scleroderma, or systemic lupus erythematosus;
• History of malignancy in the head and neck region within the past 2 years (except basal cell carcinoma) who have undergone head and neck radiation therapy and/or surgery affecting facial muscles;
• Patients who have undergone temporomandibular joint surgery or orthognathic surgery;
• Pregnant or breastfeeding women;
• Patients with poorly adapted prostheses and/or prostheses associated with inadequate increase or decrease of the vertical dimension;
• Patients with a history of tardive dyskinesia or oromandibular/cervical dystonia; -Patients with maximum mouth opening less than 35 mm;
• Patients using systemic medications with a potential effect on pain at the time of screening will not be included in the study, including analgesics, anti-inflammatory drugs, muscle relaxants, corticosteroids, or other medications with analgesic and/or anti-inflammatory effects.

If a participant initiates the use of any such medication during the follow-up period, the participant will be excluded from the study.

- Patients receiving oral and/or intravenous corticosteroid bolus therapy at doses > 1 mg/kg within the past 3 months, and those receiving biologic agents within 1 month or five times the drug half-life, whichever is longer; Individuals with mental or psychological conditions that may prevent participation in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Photobiomodulation Therapy; Participants assigned to this arm will receive photobiomodulation therapy using a dual-wavelength diode laser (810 + 980 nm) applied extraorally over standardized anatomical points corresponding to the temporomandibular joint and masticatory muscles. The intervention consists of 12 treatment sessions conducted over four weeks.	Device: Photobiomodulation Therapy; Photobiomodulation therapy (PBM) will be delivered using a dual-wavelength diode laser device (810 + 980 nm) applied extraorally over standardized anatomical points corresponding to the temporomandibular joint and masticatory muscles. The intervention is performed using a non-thermal protocol, delivering 20 J per application point. Irradiation is applied bilaterally at predefined sites, including the masseter muscle, temporomandibular joint region, and temporal muscle. The procedure is performed by trained operators according to a standardized protocol to ensure consistency across sessions. This device-based intervention aims to modulate pain, improve microcirculation, and promote functional recovery in individuals with myofascial temporomandibular disorders.
Experimental: Photobiomodulation Therapy + Exercises; Participants assigned to this arm will receive extraoral photobiomodulation therapy (PBM) using a Gemini EVO dual-wavelength diode laser (810 + 980 nm), delivering 20 J per application point over standardized anatomical points of the temporomandibular joint and masticatory muscles (six points per side). The intervention consists of 12 treatment sessions conducted over four weeks. Additionally, participants will perform a standardized home-based therapeutic exercise program once daily, including self-massage of the masseter and temporal muscles, cheek inflation exercises, and controlled mandibular opening and closing movements with tongue positioning on the palate. Written and in-person instructions, a demonstration video, daily reminders, and adherence monitoring through exercise logs will be provided.	Device: Photobiomodulation Therapy; Photobiomodulation therapy (PBM) will be delivered using a dual-wavelength diode laser device (810 + 980 nm) applied extraorally over standardized anatomical points corresponding to the temporomandibular joint and masticatory muscles. The intervention is performed using a non-thermal protocol, delivering 20 J per application point. Irradiation is applied bilaterally at predefined sites, including the masseter muscle, temporomandibular joint region, and temporal muscle. The procedure is performed by trained operators according to a standardized protocol to ensure consistency across sessions. This device-based intervention aims to modulate pain, improve microcirculation, and promote functional recovery in individuals with myofascial temporomandibular disorders.; Behavioral: Therapeutic Exercises; A standardized home-based therapeutic exercise program will be performed once daily throughout the intervention period. The protocol includes self-massage of the masseter and temporal muscles using circular fingertip movements with light to moderate pressure, cheek inflation exercises alternating sides, and controlled mandibular opening and closing movements with the tongue positioned against the palate. Written instructions and in-person guidance will be provided, along with a demonstration video to support correct execution. Participants will receive daily reminder messages, and adherence will be monitored through individual exercise logs completed throughout the study.
Sham Comparator: Sham Photobiomodulation Therapy + Exercises; Participants assigned to this arm will receive sham extraoral photobiomodulation therapy using a Gemini EVO dual-wavelength diode laser (810 + 980 nm), applied over standardized anatomical points of the temporomandibular joint and masticatory muscles with identical procedures to the active protocol, but without therapeutic energy emission to maintain participant blinding. The simulated intervention consists of 12 sessions conducted over four weeks. Additionally, participants will perform the same standardized home-based therapeutic exercise program once daily, including self-massage of the masseter and temporal muscles, cheek inflation exercises, and controlled mandibular opening and closing movements with tongue positioning on the palate. Written and in-person instructions, a demonstration video, daily reminders, and adherence monitoring through exercise logs will be provided.	Behavioral: Therapeutic Exercises; A standardized home-based therapeutic exercise program will be performed once daily throughout the intervention period. The protocol includes self-massage of the masseter and temporal muscles using circular fingertip movements with light to moderate pressure, cheek inflation exercises alternating sides, and controlled mandibular opening and closing movements with the tongue positioned against the palate. Written instructions and in-person guidance will be provided, along with a demonstration video to support correct execution. Participants will receive daily reminder messages, and adherence will be monitored through individual exercise logs completed throughout the study.; Device: Sham Photobiomodulation Therapy; Sham photobiomodulation therapy will be delivered using a Gemini EVO dual-wavelength diode laser device (810 + 980 nm) positioned and operated identically to the active PBM protocol. The device will be applied extraorally over standardized anatomical points corresponding to the temporomandibular joint and masticatory muscles; however, no therapeutic energy will be emitted, ensuring a placebo condition while maintaining participant blinding. The simulated intervention will follow the same number of sessions, duration, and procedures as the active PBM protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of Myofascial Pain Intensity	Myofascial pain intensity will be assessed using the Visual Analog Scale for Pain, ranging from 0 to 10, where 0 indicates "no pain" and 10 indicates "worst pain imaginable," with higher scores representing worse pain. Participants will rate (1) worst pain experienced in the previous 24 hours and (2) pain evoked by standardized clinical palpation. Palpation will be performed bilaterally on the masseter and temporalis muscles and on the temporomandibular joint region, using controlled and standardized pressure applied for approximately 2 seconds per palpation point by a trained examiner.	Baseline, throughout the 12 intervention sessions over 4 weeks, and at 1-month and 3-month follow-up assessments.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle Pain	Muscle and temporomandibular joint pain will be assessed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), based on a standardized and calibrated clinical examination performed by a trained examiner. The assessment includes bilateral palpation of the masticatory muscles (temporalis and masseter) and the temporomandibular joint region, using standardized pressure according to DC/TMD guidelines. Pain response is recorded as categorical outcomes, including presence or absence of pain, pain location (local or referred), and pain classification (familiar or non-familiar pain) during palpation. This assessment does not generate a numerical score and therefore has no minimum or maximum values, and higher or lower scores do not apply.	Baseline, at week 4 (after the 12th session of photobiomodulation or placebo), at 1-month and 3-month follow-up assessments.
Chronic Pain	Chronic Pain will be assessed using the Graded Chronic Pain Scale - Version 2 (GCS v2), a validated instrument that measures chronic pain severity by considering both pain intensity and functional impact. The scale assesses pain intensity (current, average, and worst pain), the degree to which pain interferes with daily activities, work/study, and social life, as well as the number of pain-related disability days over a recent reference period. Based on these components, participants are classified into chronic pain grades (0 to IV), reflecting increasing levels of pain impact and associated disability.	Baseline, at week 4 (after the 12th session of photobiomodulation or placebo), at 1-month and 3-month follow-up assessments.
Mandibular Function	Mandibular Function will be evaluated using the Jaw Functional Limitation Scale - 20 items (JFLS-20), a validated questionnaire designed to assess limitations in jaw function. The scale measures the degree of difficulty experienced during jaw-related activities, including mastication, mandibular mobility, and verbal communication. Each item is rated on a numeric scale, and item scores are summed to generate a total score ranging from 0 to 200, with higher scores indicating worse mandibular functional limitation.	Baseline, at week 4 (after the 12th session of photobiomodulation or placebo), and at 1-month and 3-month follow-up assessments.
Depressive Symptoms	Patient Health Questionnaire-9 (PHQ-9) is a validated self-report instrument that evaluates depressive symptom severity and its impact on daily functioning. The questionnaire consists of nine items assessing the frequency of core depressive symptoms experienced over the previous two weeks, including mood, sleep, energy, concentration, and interest in activities. Item scores are summed to generate a total score ranging from 0 to 27, with higher scores indicating worse depressive symptom severity.	Baseline, at week 4 (after the 12th session of photobiomodulation or placebo), and at 1-month and 3-month follow-up assessments.
Anxiety Symptoms	Anxiety symptoms will be evaluated using the Generalized Anxiety Disorder Questionnaire-7 (GAD-7), a validated self-report instrument that measures the severity of anxiety symptoms. The questionnaire consists of seven items assessing the frequency of core anxiety symptoms experienced over the previous two weeks, including nervousness, excessive worry, difficulty relaxing, and irritability. Item scores are summed to generate a total score ranging from 0 to 21, with higher scores indicating worse anxiety symptom severity.	Baseline, at week 4 (after the 12th session of photobiomodulation or placebo), and at 1-month and 3-month follow-up assessments.

Collaborators and Investigators

• Sponsor: Federal University of Rio Grande do Sul
• Investigators: Principal Investigator: Manoela Domingues Martins, DDS, MSc, PhD, Federal University of Rio Grande do Sul

Study record dates

Study Major Dates

• Study Start (Estimated): March 10, 2026
• Primary Completion (Estimated): October 1, 2030
• Study Completion (Estimated): December 1, 2030

Study Registration Dates

• First Submitted: February 24, 2026
• First Submitted That Met QC Criteria: March 5, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 5, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Photobiomodulation; Pain Management; Temporomandibular Disorder; Myofascial Pain
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Stomatognathic Diseases; Nervous System Diseases; Muscular Diseases; Joint Diseases; Jaw Diseases; Neurobehavioral Manifestations; Mandibular Diseases; Craniomandibular Disorders; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Temporomandibular Joint Disorders; Agnosia; Facial Pain; Therapeutics; Physical Therapy Modalities; Patient Care; Rehabilitation; Aftercare; Continuity of Patient Care; Laser Therapy; Phototherapy; Exercise Therapy; Low-Level Light Therapy
• Other Study ID Numbers: PBM and TMD; 408830/2024-7 (Other Identifier: Instituto Nacional de Ciência e Tecnologia - INCT)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: De-identified individual participant data collected in this study will not be made available to researchers outside the primary research group.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No