title: Phasic jaw motor episodes in healthy subjects with or without clinical signs and symptoms of sleep bruxism: a pilot study.
abstract: BACKGROUND
  To investigate the association between each clinical diagnosis criterion for sleep bruxism (SB) and the frequency of jaw motor events during sleep.
  
  
  METHODS
  Video-polysomnography was performed on 17 healthy adult subjects (mean age, 26.7 ± 2.8 years), with at least one of the following clinical signs and symptoms of SB: (1) a report of frequent tooth grinding, (2) tooth attrition with dentine exposure through at least three occlusal surfaces, (3) morning masticatory muscle symptoms, and (4) masseter muscle hypertrophy. Episodes of rhythmic masticatory muscle activity (RMMA) and isolated tonic activity were scored visually. These variables were compared with regards to the presence or absence of each clinical sign and symptom.
  
  
  RESULTS
  In 17 subjects, 4.0 ± 2.5/h (0.1-10.2) RMMA and 1.0 ± 0.8/h (0-2.4) isolated tonic episodes were observed (total episodes: 5.0 ± 2.4/h (1.2-11.6)). Subjects with self-reported grinding sounds (n=7) exhibited significantly higher numbers of RMMA episodes (5.7 ± 2.3/h) than those without (n=10; 2.8 ± 1.8/h) (p=0.011). Similarly, subjects with tooth attrition (n=6) showed significantly higher number of RMMA episodes (5.6 ± 3.1/h) than those without (n=11; 3.2 ± 1.6/h) (p=0.049). The occurrence of RMMA did not differ between the presence and absence of morning masticatory muscle symptoms or muscle hypertrophy.
  
  
  CONCLUSIONS
  Clinical signs and symptoms frequently used for diagnosing SB can represent different clinical and physiological aspects of jaw motor activity during sleep.
authors.affiliation: Department of Prosthodontics, Showa University School of Dentistry, 2-1-1, Kitasenzoku, Ohta-ku, Tokyo, 145-8515, Japan.
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Yoshizawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Suganuma
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takaba
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ono
authors.forename: Takuro
authors.initials: T
authors.lastname: Sakai
authors.forename: Ayako
authors.initials: A
authors.lastname: Yoshizawa
authors.forename: Fusae
authors.initials: F
authors.lastname: Kawana
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kato
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Baba
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D006984:Hypertrophy; D007568:Jaw / Q000503:physiopathology*; D008297:Male; D008406:Masseter Muscle / Q000473:pathology / Q000503:physiopathology; D008410:Masticatory Muscles / Q000503:physiopathology*; D017286:Polysomnography; D020186:Sleep Bruxism / Q000175:diagnosis* / Q000503:physiopathology*; D019217:Tooth Attrition / Q000175:diagnosis / Q000503:physiopathology; D014741:Video Recording