Effect of Low-level Laser Prior to the Induction of Fatigue

Study Overview
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Brief Summary
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The objective of this study is to perform an evaluation of the effect of LLLT on the prevention of fatigue in the masseter and anterior temporal muscles in young individuals with and without TMD.

Detailed Description
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Male and female individuals aged 18 to 23 years will be evaluated. The Research Diagnostic Criteria for Temporomandibular Disorders will be applied for the determination of the presence or absence of temporomandibular disorder. Each group (with and without temporomandibular disorder) will then be randomly allocated into a control group and experimental group submitted to pre-fatigue low-level laser therapy. Before and after the induction of fatigue, all volunteers will be evaluated with regard to the range of mandibular movement, bite force, sensitivity to palpation of the muscles evaluated and muscle fatigue. Low-level laser therapy will be administered to the masseter and anterior temporal muscles prior to the induction of fatigue, which will be induced with the use of chewing gum. The data will be submitted to descriptive statistical analysis. The chi-square test and Fisher's exact test will be used to establish the associations of the categorical variables. Pearson correlation coefficients will be calculated for the analysis of the correlation of the continuous variables.

Official Title
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Effect of Low-level Laser Administered to the Masseter and Anteriortemporal Muscles Prior to the Induction of Fatigue

Conditions
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Temporomandibular Joint Disorders

Intervention / Treatment
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* Device: low-level laser therapy
* Other: Placebo comparator


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female individuals aged 18 to 23 years with a signed statement of informed consent will be included in the study. Exclusion Criteria: Individuals in orthodontic or orthopedic treatment for the jaws, psychological treatment or physical therapy and those who make use of muscle relaxants, anti-inflammatory agents or bite plates will be excluded from the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 23 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: TMD control<br>Patients with diagnosis of temporomandibular disorder and that are not submitted to pre-fatigue low-level laser therapy | |
| Experimental: TMD LLL<br>Patients with diagnosis of temporomandibular disorder and that are submitted to pre-fatigue low-level laser therapy | Device: low-level laser therapy<br>* Three points will be irradiated over the masseter muscle (upper, middle and lower bundles) and one point will be irradiated over the anterior temporal muscle of each side of the face in the groups submitted to pre-fatigue laser. The following parameters will be employed: wavelength: 780 nm; energy density: 25 J/cm2; output power: 50 mW; power density: 1.25 W/cm2; and exposure time: 20 seconds per points, resulting in a total energy of 1 J per point. The laser will be applied punctually with a conventional tip in contact with the skin considering an area of 0.04 cm2.<br>|
| No Intervention: Without TMD control<br>Patients without diagnosis of temporomandibular disorder and that are not submitted to pre-fatigue low-level laser therapy | |
| Experimental: Without TMD LLL<br>Patients without diagnosis of temporomandibular disorder and that are submitted to pre-fatigue low-level laser therapy | Device: low-level laser therapy<br>* Three points will be irradiated over the masseter muscle (upper, middle and lower bundles) and one point will be irradiated over the anterior temporal muscle of each side of the face in the groups submitted to pre-fatigue laser. The following parameters will be employed: wavelength: 780 nm; energy density: 25 J/cm2; output power: 50 mW; power density: 1.25 W/cm2; and exposure time: 20 seconds per points, resulting in a total energy of 1 J per point. The laser will be applied punctually with a conventional tip in contact with the skin considering an area of 0.04 cm2.<br>|
| Placebo Comparator: TMD placebo<br>Patients with diagnosis of temporomandibular disorder and that are submitted to placebo low-level laser treatment | Other: Placebo comparator<br>* The same equipment will be used in the placebo group, but with a pen that emits a red guide light and a warning sound, but without the emission of a laser beam.<br>|
| Placebo Comparator: Without TMD placebo<br>Patients without diagnosis of temporomandibular disorder and that are submitted to placebo low-level laser treatment | Other: Placebo comparator<br>* The same equipment will be used in the placebo group, but with a pen that emits a red guide light and a warning sound, but without the emission of a laser beam.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change on Bite Force | A digital dynamometer will be used for the determination of bite force. The measurements will be taken in the region of the 1st molars. | 6 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change on range of mandibular movements | The individuals will be instructed to open their mouths as wide as possible and maximum active vertical mandibular movement (distance between maxillary and mandibular central incisors) will be recorded with the aid of digital calipers. The individuals will then be instructed to repeat the motion with pressure applied to the maxillary and mandibular teeth to obtain maximum passive vertical mandibular movement with the aid of the calipers. These measurements will be made before and after LLLT. | 6 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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temporomandibular joint, temporomandibular disorder, muscle fatigue, low-level laser therapy