title: Electromyographic evaluation of masticatory muscles at rest and maximal intercuspal positions of the mandible in children with sleep bruxism.
abstract: In adults, sleep bruxism (SB) may be related to reports of pain or fatigue in the muscles of mastication, resulting from multiple muscle contractions that occur during the night. In children, little is known about the consequences of this parafunction.
  
  
  OBJECTIVE
  The objective was to compare the electromyographic activity (EMG) of the masseter and anterior portion of the temporalis muscles in children with and without SB; acquisitions were made at rest (RE) and in maximal intercuspal (MI) positions of the mandible.
  
  
  METHODS
  Twenty children with signs and symptoms of SB (mean age 7.20 years ± 0.52) and 20 controls without signs or symptoms of SB (mean age 7.40 years ± 0.50) were selected. The controls were matched to the type of occlusal morphology evaluated according to Björk et al. (Acta Odontol Scand 22:27-40, 1964). Muscle activity was measured with the mandible at RE, MI and maximal clenching with cotton roll (MC), on the left and right sides. Data from the RE and MI (mV) were normalized by calculating them as % MC. The results were analyzed by descriptive statistics, Shapiro-Wilk test, Wilcoxon and Mann-Whitney tests.
  
  
  RESULTS
  The subjects' age did not differ significantly between groups. EMG of temporalis muscle at RE differed between the right and left sides in both groups. There was no significant difference in EMG of masseter and temporalis muscles between groups.
  
  
  CONCLUSIONS
  Children with SB showed no significant difference in EMG of masticatory muscles at RE and in MI positions of the mandible when compared with the control group.
authors.affiliation: Department of Physiology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil.
authors.forename: B de L
authors.initials: Bde L
authors.lastname: Lucas
authors.forename: T de S
authors.initials: Tde S
authors.lastname: Barbosa
authors.forename: L J
authors.initials: LJ
authors.lastname: Pereira
authors.forename: M B D
authors.initials: MB
authors.lastname: Gavião
authors.forename: P M
authors.initials: PM
authors.lastname: Castelo
mesh_terms: D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D003766:Dental Occlusion; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000503:physiopathology; D008312:Malocclusion, Angle Class II / Q000503:physiopathology; D008334:Mandible / Q000503:physiopathology; D008406:Masseter Muscle / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology*; D024343:Open Bite / Q000503:physiopathology; D057887:Overbite / Q000503:physiopathology; D020186:Sleep Bruxism / Q000503:physiopathology*; D013703:Temporal Muscle / Q000503:physiopathology*