title: Identification of the occurrence and pattern of masseter muscle activities during sleep using EMG and accelerometer systems.
abstract: BACKGROUND
  Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified.
  
  
  METHODS
  We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory.
  
  
  RESULTS
  The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%).
  
  
  CONCLUSIONS
  It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.
authors.affiliation: Department of Craniofacial Growth and Development Dentistry, Research Institute of Occlusion Medicine, Research Center of Brain and Oral Science, Kanagawa, Japan. info@yoshimishika.com
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Yoshimi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sasaguri
authors.forename: Katsushi
authors.initials: K
authors.lastname: Tamaki
authors.forename: Sadao
authors.initials: S
authors.lastname: Sato
mesh_terms: D000328:Adult; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology*; D009119:Muscle Contraction; D020186:Sleep Bruxism / Q000503:physiopathology*