Self-management and Home Exercises for the Treatment of Masticatory Muscle Pain. A Clinical Trial

The objective of this study was to compare the clinical effectiveness of self-management (SM) together with mandibular home exercises (EX) in the treatment of myalgia of the masticatory muscles. A controlled clinical trial was carried out with a total of 48 subjects diagnosed with myalgia according to the diagnostic criteria for temporomandibular disorders (DC/TMD), who were randomized into two groups: treated with SM (SM group) and treated with SM and mandibular home exercises (SM-EX group). The follow-ups were carried out at 2, 6 and 10 weeks, where the following were evaluated: pain in the masticatory muscles, range of mandibular movement and mandibular functional limitation.

Materials and method. This randomized controlled clinical trial was conducted between January 2016 and June 2016 at the Andres Bello University Dental Clinic (Viña del Mar, Chile). Study subjects were recruited from the universe of patients seeking treatment for jaw pain at the School of Dentistry. All subjects were informed about the study by their operator and gave their written consent before beginning the study. The protocol, design, and implementation were approved by the Scientific Ethics Committee of the Faculty of Dentistry of the Andres Bello University, Viña del Mar, Chile (Folio No. 056, year 2016). Which was in accordance with the latest version of the Declaration of Helsinki of the World Medical Association (Declaration of the World Medical Association of Helsinki, 2013).

Sample's size calculation. An error percentage of 7% was calculated according to a confidence level of 91%, considering a prevalence of chewing muscle pain of 9% and an expected loss of 1.08% based on the losses obtained in the study carried out by Kalamir. et al. in 2012 (Kalamir et al., 2012). The minimum number of participants required for each group was 25 patients (50 patients in total).

Randomization and interventions. After meeting the inclusion and exclusion criteria, subjects were randomly assigned to two groups using a computer generated sequence "random list" developed by random.org.

Evaluation methods. The initial evaluation, to determine the degree of involvement of axis I, was carried out following the symptom questionnaire and clinical examination guidelines according to the DC/TMD protocol. Additionally, the questionnaire for the chronic pain grade scale (GCPS v2.0) and the functional limitation scale (JFLS-20) of axis II of the DC/TMD protocol were applied. In turn, an intraoral clinical examination was performed to rule out pain of dental origin.

Statistic analysis. Demographic characteristics of the sample were reported descriptively. Data were analyzed using Wilcoxon signed-rank test for comparisons between periods (initial evaluation, and weeks 2, 6, and 10) and Wilcoxon rank-sum test for comparison between groups of the variables MMP, MRM, JFLS-20. Qualitative evaluation of adherence to self-management was analyzed using Fisher exact test. Qualitative evaluation of adherence to home exercises was descriptively reported. The level of significance was established at p=0.05. All statistical analysis was performed using R-Crain 3.01 software.

Eligibility Criteria:
Inclusion Criteria:

* "Age between 18 and 40 years", "Presence of myalgia of the masticatory muscles according to DC / TMD diagnostic criteria."

Exclusion Criteria:

* "Painful joint TMD"; "history of treatment for TMD"; "recent history of facial or cervical trauma"; "ongoing orthodontic treatment"; "Tooth mobility secondary to periodontal disease"; "Subjects with loss of more than two teeth other than third molars and / or premolars due to orthodontic indication"; "subjects with systemic musculoskeletal diseases or who are under analgesic treatment"; "Subjects with a diagnosed intellectual disability who cannot express their will to participate in scientific research as established by law 20.584 of Chile."