title: Association between rhythmic masticatory muscle activity during sleep and masticatory myofascial pain: a polysomnographic study.
abstract: OBJECTIVE
  To test for an association between rhythmic masticatory muscle activity during sleep, as assessed according to polysomnographic criteria for sleep bruxism (RMMA-SB), and myofascial pain (MFP), as well as the chance of occurrence of MFP in patients with RMMA-SB.
  
  
  METHODS
  Thirty MFP patients (diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders) and 30 age- and gender-matched asymptomatic controls underwent a polysomnographic examination. Also, any self-reporting of daytime clenching (DC) was registered in 58 of these subjects.
  
  
  RESULTS
  Most MFP patients reported mild or moderate pain (46.67% and 43.33%, respectively), and only 3 (10%) reported severe pain. Pain duration ranged from 2 to 120 months (mean 34.67 +/- 36.96 months). Significant associations were observed between RMMA-SB and MFP as well as between DC and MFP.
  
  
  CONCLUSIONS
  (1) RMMA-SB is significantly associated with MFP; (2) although RMMA-SB represents a risk factor for MFP, this risk is low; and (3) DC probably constitutes a stronger risk factor for MFP than RMMA-SB.
authors.affiliation: leylharossetti@uol.com.br
authors.forename: Leylha Maria Nunes
authors.initials: LM
authors.lastname: Rossetti
authors.forename: Carlos Dos Reis
authors.initials: Cdos R
authors.lastname: Pereira de Araujo
authors.forename: Paulo Henrique Orlato
authors.initials: PH
authors.lastname: Rossetti
authors.forename: Paulo César Rodrigues
authors.initials: PC
authors.lastname: Conti
mesh_terms: D000328:Adult; D002012:Bruxism / Q000150:complications / Q000503:physiopathology; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology; D008410:Masticatory Muscles / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D009334:Neck Muscles / Q000503:physiopathology; D010147:Pain Measurement; D020447:Parasomnias / Q000150:complications; D017286:Polysomnography; D016059:Range of Motion, Articular / Q000502:physiology; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000150:complications; D020186:Sleep Bruxism / Q000150:complications* / Q000503:physiopathology; D013703:Temporal Muscle / Q000503:physiopathology; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000209:etiology*; D013997:Time Factors