title: Impact of functional appliances on muscle activity: a surface electromyography study in children.
abstract: BACKGROUND
  Electromyography (EMG) is the most objective tool for assessing changes in the electrical activity of the masticatory muscles. The purpose of the study was to evaluate the tone of the masseter and anterior temporalis muscles in growing children before and after 6 months of treatment with functional removable orthodontic appliances.
  
  
  METHODS
  The sample conisted of 51 patients with a mean age 10.7 years with Class II malocclusion. EMG recordings were performed by using a DAB-Bluetooth instrument (Zebris Medical GmbH, Germany). Recordings were performed in mandibular rest position, during maximum voluntary contraction (MVC), and during maximum effort.
  
  
  RESULTS
  The results of the study indicated that the electrical activity of the muscles in each of the clinical situations was the same in the group of girls and boys. The factor that determined the activity of the muscles was their type. In mandibular rest position and in MVC, the activity of the temporalis muscles was significantly higher that that of the masseter muscels. The maximum effort test indicated a higher fatigue in masseter than in temporalis muscles.
  
  
  CONCLUSIONS
  Surface electromyography is a useful tool for monitoring muscle activity. A 6-month period of functional therapy resulted in changes in the activity of the masticatory muscles.
authors.affiliation: Department of Orthodontics, Pomeranian Medical University of Szczecin, Szczecin, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Woźniak
authors.affiliation: Department of Orthodontics, Pomeranian Medical University of Szczecin, Szczecin, Poland.
authors.forename: Dagmara
authors.initials: D
authors.lastname: Piątkowska
authors.affiliation: Department of Orthodontics, Pomeranian Medical University of Szczecin, Szczecin, Poland.
authors.forename: Liliana
authors.initials: L
authors.lastname: Szyszka-Sommerfeld
authors.affiliation: Department of Conservative Dentistry, Pomeranian Medical University of Szczecin, Szczecin, Poland.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Buczkowska-Radlińska
mesh_terms: D002648:Child; D004566:Electrodes; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000473:pathology; D008410:Masticatory Muscles / Q000473:pathology*; D009119:Muscle Contraction; D009132:Muscles / Q000473:pathology; D009967:Orthodontic Appliances; D012737:Sex Factors; D012815:Signal Processing, Computer-Assisted