title: Short-term transcutaneous electrical nerve stimulation reduces pain and improves the masticatory muscle activity in temporomandibular disorder patients: a randomized controlled trial.
abstract: OBJECTIVE
  To investigate the short-term effect of transcutaneous electrical nerve stimulation (TENS) by examining pain intensity, pressure pain threshold (PPT) and electromyography (EMG) activity in patients with temporomandibular disorder (TMD).
  
  
  METHODS
  Forty patients with myofascial TMD were enrolled in this randomized placebo-controlled trial and were divided into two groups: active (n=20) and placebo (n=20) TENS. Outcome variables assessed at baseline (T0), immediately after (T2) and 48 hours after treatment (T1) were: pain intensity with the aid of a visual analogue scale (VAS); PPT of masticatory and cervical structures; EMG activity during mandibular rest position (MR), maximal voluntary contraction (MVC) and habitual chewing (HC). Two-way ANOVA for repeated measures was applied to the data and the significance level was set at 5%.
  
  
  RESULTS
  There was a decrease in the VAS values at T1 and T2 when compared with T0 values in the active TENS group (p<0.050). The PPT between-group differences were significant at T1 assessment of the anterior temporalis and sternocleidomastoid (SCM) and T2 for the masseter and the SCM (p<0.050). A significant EMG activity reduction of the masseter and anterior temporalis was presented in the active TENS during MR at T1 assessment when compared with T0 (p<0.050). The EMG activity of the anterior temporalis was significantly higher in the active TENS during MVC at T1 and T2 when compared with placebo (p<0.050). The EMG activity of the masseter and anterior temporalis muscle was significantly higher in the active TENS during HC at T1 when compared with placebo (p<0.050).
  
  
  CONCLUSIONS
  The short-term therapeutic effects of TENS are superior to those of the placebo, because of reported facial pain, deep pain sensitivity and masticatory muscle EMG activity improvement.
authors.affiliation: Universidade Federal de Pernambuco, Departamento de Fisioterapia, Recife, PE, Brasil.
authors.forename: Ana Paula de Lima
authors.initials: AP
authors.lastname: Ferreira
authors.affiliation: Universidade Federal de Sergipe, São Cristóvão, SE, Brasil.
authors.forename: Dayse Regina Alves da
authors.initials: DR
authors.lastname: Costa
authors.affiliation: Universidade Federal de Pernambuco, Programa de Pós-Graduação em Neuropsiquiatria e Ciências do Comportamento, Recife, PE, Brasil.
authors.forename: Ana Izabela Sobral de
authors.initials: AI
authors.lastname: Oliveira
authors.affiliation: Universidade Federal de Sergipe, Departamento de Engenharia Elétrica, São Cristóvão, SE, Brasil.
authors.forename: Elyson Adam Nunes
authors.initials: EA
authors.lastname: Carvalho
authors.affiliation: Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Prótese, Bauru, SP, Brasil.
authors.forename: Paulo César Rodrigues
authors.initials: PC
authors.lastname: Conti
authors.affiliation: Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Ciências Biológicas, Seção de Fisiologia da Cabeça e da Face, Bauru, SP, Brasil.
authors.forename: Yuri Martins
authors.initials: YM
authors.lastname: Costa
authors.affiliation: Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Ciências Biológicas, Seção de Fisiologia da Cabeça e da Face, Bauru, SP, Brasil.
authors.forename: Leonardo Rigoldi
authors.initials: LR
authors.lastname: Bonjardim
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D005157:Facial Pain / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold; D015990:Placebo Effect; D015203:Reproducibility of Results; D013703:Temporal Muscle / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology* / Q000628:therapy*; D013997:Time Factors; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult