An interventional study of Low-level laser auriculotherapy (LLLT-AT) and Sham Low-level laser auriculotherapy (sham LLLT-AT) in Temporomandibular Disorder and Anxiety State, sponsored by Quiropraxia y Equilibrio. Not yet recruiting at 1 site in Chile. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-08-15.
Sponsored by Quiropraxia y Equilibrio · Not applicable, Interventional, and Treatment
Summary:
Low-level laser auriculotherapy (LLLT-AT) is a non-invasive technique that has gained attention for managing musculoskeletal pain and anxiety. Given the painful and emotional components of temporomandibular disorders (TMD), LLLT-AT may offer therapeutic benefits by stimulating auricular points associated with pain modulation and anxiety reduction. This randomized, placebo-controlled, two-arm clinical trial with blinded outcome assessors aims to evaluate the effects of LLLT-AT in individuals diagnosed with myogenic TMD (Axis I, Group I of the DC/TMD classification) and anxiety. The study will be conducted at the Physical Agents Laboratory of Universidad Andrés Bello. Eligible participants will include members of the university community with myogenic TMD (Axis I, Group I of the DC/TMD classification) and anxiety. Participants will be stratified by sex and randomly assigned to either an experimental group receiving LLLT-AT combined with a standardized myofascial release protocol or a control group receiving sham LLLT-AT with the same myofascial protocol. Interventions will be administered twice weekly for three weeks. Outcome measures will be collected at baseline, post-intervention, and at a four-week follow-up. Primary outcomes include pressure pain threshold (PPT), assessed by algometry, and anxiety level, measured using the GAD-7 scale. Secondary outcomes include maximum mouth opening range of motion (MMOROM) and mandibular functional limitation (MFL), assessed using the Jaw Functional Limitation Scale 8 (JFLS-8).
Material and Methods
Study design:
A double-blind, randomized, placebo-controlled trial with two parallel groups.
Study population:
Participants will include students, faculty, and administrative staff from Universidad Andrés Bello, Casona de Las Condes Campus. Recruitment will be conducted through institutional channels such as bulletin boards, digital posters, and official emails. Interested individuals will be invited for an in-person screening at the Physical Agents Laboratory (KIN 401, Building C5) of the School of Rehabilitation Sciences. The screening will involve a study explanation, eligibility assessment, and a physical examination conducted by an experienced physiotherapist to confirm a myogenic temporomandibular disorder (Axis I, Group I, DC/TMD classification).
Sample size and randomization:
Sample size will be calculated using G*Power® software, assuming a statistical power of 80% (1-β), a significance level of 0.05 (α), a 95% confidence level, and an estimated effect size of 1.0. This value is based on the study by Sancakli et al. (see reference), who reported an increase in the pressure pain threshold (PPT) of the masseter muscle in patients with myogenic temporomandibular disorders following four weeks of treatment with low-level laser therapy (LLLT). The minimum estimated sample size is 28 participants, 14 per group (LLLT-AT plus myofascial release and sham LLLT-AT plus myofascial release). To account for potential data loss or participant dropout during the study, researchers will apply a 15% increase to the calculated sample size. This decision aligns with item 8 of the Physiotherapy Evidence Database (PEDro) scale, which requires that outcome measures be obtained from at least 85% of participants. Therefore, a minimum of 16 participants per group will be recruited.
Selected participants will be allocated into two groups through a simple randomization process: experimental group (LLLT-AT) and control group (sham LLLT-AT). Additionally, stratification by sex will be performed to ensure an equal proportion of male and female participants in each group. Randomization will be carried out using the web-based tool Research Randomizer (https://www.randomizer.org/). FFollowing the laser intervention, both the experimental and control groups will receive bilateral myofascial release treatment targeting the masticatory muscles (masseter and temporalis) (35). Participants will be blinded to group allocation.
Selection criteria
Interventions:
The experimental group will receive two weekly sessions of low-level laser auriculotherapy (LLLT-AT), while the control group will receive two weekly sessions of sham LLLT-AT. Sessions will be scheduled with a two-day interval between each session. Both groups will receive a standard manual therapy protocol consisting of bilateral myofascial release of the masseter and temporalis muscles. A total of six treatment sessions will be administered over three weeks.
Outcome Measures:
Primary outcomes will include changes in pressure pain threshold (PPT) and anxiety level (AL). Secondary outcomes will include changes in maximum mandibular opening range of motion (MMOROM) and mandibular functional limitation (MFL). All assessments will be performed by a blinded independent evaluator. PPT will be measured using algometry at two bilateral points associated with the masseter and temporalis muscles. AL, MMOROM, and MFL will be assessed using the Generalized Anxiety Disorder 7-item scale (GAD-7), a millimeter ruler, and the 8-item Jaw Functional Limitation Scale (JFLS-8), respectively. Assessments will be conducted at three time points: baseline (T0), post-treatment (T1: after the 6th LLLT-AT session, end of week 3), and follow-up (T2: 4 weeks after the end of treatment).
Variables
Conceptual Definition of Study Variables:
Operational Definition of Study Variables:
Study Variable Type
Study phases
The study will be conducted in three phases:
- Phase 1 - Screening (2 weeks): A digital screening questionnaire will be distributed to the target population to identify potentially eligible participants. Responses will be reviewed to assess initial eligibility based on inclusion criteria. Individuals who meet the criteria will be contacted and invited to participate. Written informed consent will be obtained prior to enrollment.
- Phase 2 - Baseline Assessment (2 weeks): Participants will undergo a standardized physical examination to confirm the presence of myogenic TMD, based on the DC/TMD diagnostic criteria. A trained physiotherapist will perform bilateral palpation of the masseter and temporalis muscles. Those presenting localized or referred pain during palpation will be considered eligible. Participants with positive findings will complete the GAD-7 questionnaire to assess anxiety levels.
- Phase 3 - Intervention and Follow-up (3 weeks + 4-week follow-up): Eligible participants will be randomly assigned to one of two groups: (1) an experimental group receiving LLLT-AT and (2) a control group receiving sham LLLT-AT. Both groups will also receive standardized bilateral myofascial release of the masseter and temporalis muscles. Treatment will be delivered twice per week for three weeks. Primary and secondary outcomes-including PPT, AL, MMOROM, and MFL-will be assessed at baseline, after the intervention, and at 4-week follow-up. All evaluations will be conducted by a blinded assessor, and data will be recorded and managed using Microsoft Excel®.
For inferential analysis, parametric or non-parametric tests will be selected based on the normality assessment. If normal distribution is confirmed, a two-way ANOVA (factors: group and time) will be applied. If data are non-normally distributed, the Kruskal-Wallis test will be used. Post-hoc analyses will be conducted using Bonferroni or Tukey corrections, as appropriate to the primary test used.
All analyses will be performed using IBM SPSS Statistics version 26, with the significance level set at p \< 0.05.
591 studies on the registry are indexed under Temporomandibular Joint Disorders; 149 are open to participants now.
This study's planned enrollment of 32 is below the median of 45 across 415 interventional studies indexed under Temporomandibular Joint Disorders.
Browse Temporomandibular Joint Disorders studies →Quiropraxia y Equilibrio is the lead sponsor of 12 studies on the registry; 3 are open to participants now.
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Exclusion Criteria:
Discontinuation Criteria
- The participant's withdrawal or non-attendance results in the failure to complete the evaluation or treatment protocol.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive low-level laser auriculotherapy (LLLT-AT) using an infrared class IIIb diode laser (905 nm). The laser will be applied to four auricular acupuncture points: Shenmen (TF4), Kidney (AH9), Liver (AH11), and Point Zero (O'), following the protocol by Marques et al. (2023). Each point will receive 4 J of energy (total of 16 J per session) with an average output power of 71 mW over 224 seconds. The treatment will be applied to the auricle ipsilateral to the symptomatic TMJ or to the more painful side in bilateral cases. In addition to LLLT-AT, the experimental group will receive a baseline manual therapy treatment consisting of bilateral myofascial release of the masseter and temporalis muscles. A total of six sessions will be delivered over a period of three weeks.
Radiation: Low-level laser auriculotherapy (LLLT-AT) · Other: Myofascial release
Participants in the sham laser group will be treated under the same conditions as the experimental group, using the same device (COMBI 400L, Gymna®), dosage parameters, and safety procedures. However, a simulated laser emission will be used by disconnecting the probe, thereby preventing the laser beam from being emitted. The laser will be applied to the same four auricular points as in the experimental group. This sham condition is unlikely to be perceived by participants, as low-level laser therapy is athermal and does not produce noticeable sensations during application. In addition to sham LLLT-AT, this group will receive a baseline manual therapy treatment consisting of bilateral myofascial release of the masseter and temporalis muscles. A total of six sessions will be delivered over a period of three weeks.
Other: Sham Low-level laser auriculotherapy (sham LLLT-AT) · Other: Myofascial release
Low-Level Laser Auriculotherapy (LLLT-AT) is a non-invasive, painless treatment that applies infrared laser (class IIIb, 905 nm) to specific auricular acupuncture points. It aims to reduce musculoskeletal pain and anxiety by stimulating mitochondrial cytochrome c oxidase, increasing ATP production, promoting tissue repair, and modulating inflammation. LLLT also reduces nerve excitability and triggers β-endorphin release, aiding in pain control. Auricular stimulation may influence autonomic nervous system activity, impacting both physical and emotional symptoms. The intervention consists of two sessions per week over three weeks, following standard laser safety procedures.
Also known as: Laser Auriculotherapy, Auricular Photobiomodulation Therapy
Sham LLLT-AT replicates the active procedure using the same laser device and parameters, but without light emission. The probe will be deactivated and applied to the same auricular points twice weekly for three weeks. As LLLT is painless and athermal, participants are unlikely to distinguish the sham condition. Standard safety protocols will be maintained.
Also known as: Sham Laser auriculotherapy, Sham Auricular Photobiomodulation Therapy
Myofascial release is a manual therapy applied bilaterally to the masseter and temporalis muscles as a baseline intervention. Each session includes 1 minute of ischemic pressure, 1 minute of myofascial release, 30 seconds of positional release, and 30 seconds of general mobilization per muscle. The protocol consists of two sessions per week for three weeks (six sessions total), aiming to reduce muscle tension and improve mandibular function.
Pain pressure thereshold (PPT)
PPT will be assessed via algometry with the participant in a supine position. Four bilateral points on the masseter and temporalis muscles will be evaluated. Each point will be measured three times with 30-second intervals, and the average of each set will be calculated. The final PPT score will be the sum of the four-point averages, expressed in lb/cm². Data will be recorded in Microsoft Excel®.
Time frame: Baseline, 3 weeks (6 sessions) and 4 weeks (follow-up)
Anxiety level (AL)
AL will be assessed using the GAD-7 scale, a validated 7-item questionnaire scored from 0 to 3. It measures anxiety symptoms over the past month, with higher total scores indicating greater severity. The total score (0-21) will be calculated by summing all item responses. The GAD-7 is validated in Spanish and has demonstrated good sensitivity (0.83) and moderate specificity (0.46).
Time frame: Baseline, 3 weeks (6 sessions) and 4 weeks (follow-up)
Maximum mandibular opening range of motion (MMOROM)
MMOROM will be measured with the participant in a supine position, head in neutral alignment. The distance between the incisal edges of the upper and lower central incisors during maximum mouth opening will be recorded using a millimeter ruler.
Time frame: Baseline, 3 weeks (6 sessions) and 4 weeks (follow-up)
Mandibular functional limitation (MFL)
MFL will be assessed using the JFLS-8, an 8-item Likert-scale questionnaire measuring limitations in jaw function, including chewing, mouth opening, and verbal/non-verbal communication. Each item is scored from 0 (no limitation) to 10 (severe limitation). The total score will reflect the maximum reported limitation. The scale is validated in Spanish and has high reliability (ICC = 0.94-0.96) and strong correlation with the 20-item version (r = 0.86).
Time frame: Baseline, 3 weeks (6 sessions) and 4 weeks (follow-up)
Plan to share: No
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