title: Rhythm and amplitude of rhythmic masticatory muscle activity during sleep in bruxers - comparison with gum chewing.
abstract: OBJECTIVE
  The aim of this study was to elucidate characteristics of rhythmic masticatory muscle activity (RMMA) during sleep by comparing masseteric EMG (electromyogram) activities of RMMA with gum chewing.
  
  
  METHODS
  The parts of five or more consecutive phasic bursts in RMMA of 23 bruxers were analyzed. Wilcoxon signed-rank test for matched pairs and Spearman's correlation coefficient by the rank test were used for statistical analysis.
  
  
  RESULTS
  Root mean square value of RMMA phasic burst was smaller than that during gum chewing, but correlates to that of gum chewing. The cycle of RMMA was longer than that of gum chewing due to the longer burst duration of RMMA, and variation in the cycles of RMMA was wider.
  
  
  CONCLUSIONS
  These findings suggest that the longer but smaller EMG burst in comparison with gum chewing is one of the characteristics of RMMA. The relation between size of RMMA phasic bursts and gum chewing is also suggested.
authors.affiliation: a Division of Dentistry and Oral Surgery, Faculty of Medical Sciences, Department of Sensory and Locomotor Medicine , University of Fukui , Fukui , Japan.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Matsuda
authors.affiliation: b Division of Oral Functional Science, Department of Crown and Bridge Prosthodontics , Graduate School of Dental Medicine, Hokkaido University , Hokkaido , Japan.
authors.forename: Taihiko
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: c Department of Temporomandibular Disorders , Center for Advanced Oral Medicine, Hokkaido University Hospital , Hokkaido , Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Mikami
authors.affiliation: c Department of Temporomandibular Disorders , Center for Advanced Oral Medicine, Hokkaido University Hospital , Hokkaido , Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Okada
authors.affiliation: c Department of Temporomandibular Disorders , Center for Advanced Oral Medicine, Hokkaido University Hospital , Hokkaido , Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Gotouda
authors.affiliation: a Division of Dentistry and Oral Surgery, Faculty of Medical Sciences, Department of Sensory and Locomotor Medicine , University of Fukui , Fukui , Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sano
mesh_terms: D000328:Adult; D002638:Chewing Gum; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000502:physiology / Q000503:physiopathology*; D020186:Sleep Bruxism / Q000503:physiopathology*
chemical_list: D002638:Chewing Gum
keywords: Electromyogram; Gum chewing; Phasic burst; Rhythmic Masticatory Muscle Activity; Sleep bruxism