title: Electromyographic muscular activity improvement in Class II patients treated with the pre-orthodontic trainer.
abstract: OBJECTIVE
  A study was designed to determine changes in the amplitude of the EMG muscular activity of the Masseter and Temporalis muscles at clench in children with a Class II, division 1 malocclusion treated with the pre-orthodontic Trainer functional appliance, for 12 months.
  
  
  METHODS
  36 Class II, division 1 malocclusion patients (mean age 7.6 ± 1.3 years) composed the treated group and wore the functional appliance; 22 children with a similar age and malocclusion composed the untreated controls; and, 20 children with no dental malocclusion participated as normal controls. Electromyographic (EMG) muscular activity of the Temporalis and Masseter muscles were recorded before and after treatment.
  
  
  RESULTS
  Subjects in the treated group reported a bilateral significant increase in the muscular electrical activity in the both tested muscles (p < 0.001). After treatment, they recorded values similar to those measured in normal controls, whereas the untreated controls remained on lower values.
  
  
  CONCLUSIONS
  These results confirm that treatment with the pre-orthodontic Trainer functional appliance significantly increases the EMG muscular activity in the Temporalis and Masseter muscles at clench in patients with Class II, division 1 malocclusion.
authors.affiliation: I.I. Mechnikov North-Western State Medical University, Saint Petersburg, Russia.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Satygo
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Silin
authors.forename: German O
authors.initials: GO
authors.lastname: Ramirez-Yañez
mesh_terms: D002648:Child; D004576:Electromyography / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000503:physiopathology / Q000628:therapy*; D008406:Masseter Muscle / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D017289:Orthodontic Appliances, Functional; D063173:Retrognathia / Q000503:physiopathology / Q000628:therapy; D013703:Temporal Muscle / Q000503:physiopathology*