Administration of Low-level Laser on Muscles of Mastication Following the Induction of Initial Fatigue

Orofacial pain encompasses painful conditions, such as temporomandibular disorder. Multidisciplinary health teams seek to control such musculoskeletal disorders to improve the quality and functional capacity of the muscles of mastication. The aim of the proposed study is to evaluate the effect of low-level laser therapy as a form of treatment for the prevention of initial fatigue of the muscles of mastication (masseter and anterior temporal muscles) as well as the recovery of these muscles after induced exhaustion (caused by isometric contraction) in young adults. The participants will be 78 (n obtained from calculation of the sample size with p < 0.05) healthy male and female volunteers between 18 and 34 years of age. The volunteers will be randomly allocated to a laser group (n = 26), sham group (n = 26) and control group (n = 26). All participants will be submitted to a clinical evaluation to record mandibular movements, bite force, muscle sensitivity to palpation and initial muscle fatigue. Initial fatigue will be induced by isometric contraction of the jaws. Maximum voluntary contraction will be performed to record the time until initial exhaustion of the masseter muscle (determined by electromyography). The groups will then be submitted to the interventions: 1) active laser therapy (wavelength: 780 nm; fluence: 134 J/cm2; power: 50 mW; irradiance: 1.675 W/cm2; exposure time: 80 seconds per point) on three points of the masseter and one point on the anterior temporal muscles on each side, 2) sham laser (placebo effect) or 3) no intervention (control). Maximum voluntary contraction will be performed again after the interventions to record the time until initial exhaustion of the masseter muscle (determined by electromyography). Differences in individual time until exhaustion between the pre-intervention and post-intervention evaluations will be measured to determine the effect of low-level laser therapy.

Study Overview

• Status: Unknown
• Conditions: Muscle Fatigue
• Intervention / Treatment: Radiation: Active laser; Radiation: Sham laser; Diagnostic test: Control group

• Study Type: Interventional
• Enrollment (Anticipated): 78
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Greice B Bitencourt, MS; Phone Number: 5511998359996; Email: greicebrito@hotmail.com

Study Locations

• Brazil
  • SP
    • São Paulo, SP, Brazil, 01504001
      • Recruiting
      • University Nove de Julho
      • Contact: Greice B Bitercourt, MS; Phone Number: 5511998359996; Email: greicebrito@hotmail.com
      • Sub-Investigator: Sandra K Bussadori, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 34 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• will be included in this study young people in the age range between 18-34 years, without diagnosis of temporomandibular disorder (TMD) and with the signed free informed consent term.

Exclusion Criteria:

• will be excluded from the study individuals who are in orthodontic or orthopedic treatment of the jaw, psychological and / or physiotherapy. Also excluded are those who are taking anti-inflammatory drugs and anti-inflammatory drugs and occlusal plaques.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active laser; Three points on the masseter muscle (upper, middle and lower portions) and one point on the anterior temporal on each side of the face will be irradiated with a wavelength of 780 nm, radiant exposure of 134 J/cm2, power of 50 mW and irradiance of 1.675 W/cm2 for 80 seconds per point, resulting in an energy of 4 J per point and total energy of 32 J per volunteer.20,21 Point application will be performed with a conventional tip in contact with the skin (beam spot: 0.04 cm2).	Radiation: Active laser; Three points on the masseter muscle (upper, middle and lower portions) and one point on the anterior temporal on each side of the face will be irradiated with a wavelength of 780 nm, radiant exposure of 134 J/cm2, power of 50 mW and irradiance of 1.675 W/cm2 for 80 seconds per point, resulting in an energy of 4 J per point and total energy of 32 J per volunteer.20,21 Point application will be performed with a conventional tip in contact with the skin (beam spot: 0.04 cm2).
Sham Comparator: Sham laser; The same procedures will be performed in the sham group, but the device will be switched off and a recording of the emission sounds will be used to give the volunteer the auditory sensation of laser therapy.	Radiation: Sham laser; The same procedures will be performed in the sham group, but the device will be switched off and a recording of the emission sounds will be used to give the volunteer the auditory sensation of laser therapy.
Other: Control group; In this group, no treatment will be done, we will only induce fatigue, for evaluation.	Diagnostic test: Control group; In this group, we will only induce fatigue.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change of the masseter muscle strength determined by electromyography before and after treatment	MVC (clenching the teeth in maximum intercuspation) will be performed to record the time until initial exhaustion of the masseter muscle (determined by electromyography). The groups will then be submitted to the interventions and MVC will be performed a second time to record the time until initial exhaustion of the masseter muscle (determined by electromyography). During the procedures, the volunteers will receive verbal encouragement as well as visual feedback on the monitor to maintain MVC. Before the readings, the volunteers will undergo training of the procedure for the acquisition of the EMG signal.	Before and immediately after treatment

Collaborators and Investigators

• Sponsor: University of Nove de Julho

Study record dates

Study Major Dates

• Study Start (Actual): November 20, 2017
• Primary Completion (Anticipated): April 1, 2018
• Study Completion (Anticipated): July 1, 2018

Study Registration Dates

• First Submitted: December 5, 2017
• First Submitted That Met QC Criteria: March 7, 2018
• First Posted (Actual): March 9, 2018

Study Record Updates

• Last Update Posted (Actual): March 9, 2018
• Last Update Submitted That Met QC Criteria: March 7, 2018
• Last Verified: March 1, 2018

More Information

Terms related to this study

• Keywords: Masseter muscle; initial fatigue; low-level laser
• Additional Relevant MeSH Terms: Fatigue
• Other Study ID Numbers: 919822905; 290582 (Other Identifier: uninove)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No