title: Changes in electric activity of masseter and anterior temporalis muscles before and after orthognathic surgery in skeletal class III patients.
abstract: OBJECTIVE
  The purpose of this study was to evaluate, through clinical and electromyographic (EMG) assessments, the electric activity of masseter muscle and anterior temporalis muscles during clenching, before and after orthodontic treatment and mandibular setback, with or without LeFort I osteotomy, for correction of mandibular excess.
  
  
  METHODS
  Seventeen adult patients (10 males, 7 females, mean age: 22.5 ± 2.4 years) were recruited for this study. All patients received orthodontic treatment and surgical corrections. EMG recordings were obtained from 4 channels of the 8-channel electromyograph FREELY (DeGoetzen spa, Olgiate Olona, VA, Italy).
  
  
  RESULTS
  A significant difference was found in the value of activity index at T0-T1 (33% T0, 1% T1) (P < .05), of asymmetry index at T0-T1 (21% T0, 4% T1) (P < .05), and of torque index at T0-T1 (24% T0, 5% T1) (P < .05).
  
  
  CONCLUSIONS
  The evaluation of EMG activity after surgery may be considered a sign of good adaptation of the neuromuscular system to the new occlusal condition and a good method for detecting nonresponding patients who might require further treatment.
authors.affiliation: Department of Orthodontics and Gnathology-Masticatory Function, University of Turin, Italy. Electronic address: gianluigi_frongia@msn.com.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Frongia
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Ramieri
authors.forename: Corrado
authors.initials: C
authors.lastname: De Biase
authors.forename: Pietro
authors.initials: P
authors.lastname: Bracco
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Piancino
mesh_terms: D004576:Electromyography; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008334:Mandible / Q000601:surgery*; D008406:Masseter Muscle / Q000502:physiology*; D008437:Maxilla / Q000601:surgery*; D009971:Orthodontics, Corrective; D057909:Orthognathic Surgery / Q000379:methods; D019340:Osteotomy, Le Fort; D059229:Osteotomy, Sagittal Split Ramus; D013703:Temporal Muscle / Q000502:physiology*; D016896:Treatment Outcome; D055815:Young Adult