title: Association between masseter muscle activity levels recorded during sleep and signs and symptoms of temporomandibular disorders in healthy young adults.
abstract: OBJECTIVE
  To examine whether any signs and symptoms of temporomandibular disorders were significantly associated with masseter muscle activity levels during sleep.
  
  
  METHODS
  One hundred three healthy adult subjects (age range, 22 to 32 years) participated in the study. They were asked to fill out questionnaires, undergo a calibrated clinical examination of their jaws and teeth, and perform 6 consecutive nightly masseter electromyographic (EMG) recordings with a portable EMG recording system in their home. The EMG data were considered dependent variables, while the questionnaire and examination data were considered independent variables. Multiple stepwise linear regression analysis was utilized to assess possible associations between these variables.
  
  
  RESULTS
  Both gender and joint sound scores were significantly related to the duration of EMG activity. None of the other independent variables were found to be related to any of the muscle activity variables.
  
  
  CONCLUSIONS
  The results suggest that both gender and clicking are significantly related to duration of masseter EMG activity during sleep.
authors.affiliation: Removable Prosthodontics, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku Tokyo, Japan. kazu.rpro@tmd.ac.jp
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Baba
authors.forename: Tadasu
authors.initials: T
authors.lastname: Haketa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohyama
authors.forename: Glenn T
authors.initials: GT
authors.lastname: Clark
mesh_terms: D000328:Adult; D002012:Bruxism / Q000150:complications* / Q000503:physiopathology; D004576:Electromyography; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology*; D012737:Sex Factors; D013016:Sound; D013705:Temporomandibular Joint Disorders / Q000209:etiology* / Q000503:physiopathology