title: Electromyographic characteristic of orbicularis oris in patients with dental crowding in permanent occlusion.
abstract: BACKGROUND
  electromyographic indices were developed for complex analysis of functional condition of orbicularis oris.
  
  
  OBJECTIVE
  to study electromyographic indices of orbicularis oris in patients with dental crowding in permanent occlusion.
  
  
  METHODS
  thirty four patients with malocclusion and a severe degree of severity of dental crowding (15 males, 19 females, aged 16-29 years) who underwent orthodontic examination. The treatment group was divided into three: Group Ia comprised 11 subjects with mandibular crowding (mean age 19,27 ± 1,08 years); group Ib, 10 patients with maxillary dental crowding (mean age 20,10 ± 1,60 years) and group Ic, 13 subjects with both maxillary and mandibular crowding (mean age 20,15 ± 1,45 years). The control group consisted of 10 patients with malocclusions but without dental crowding (mean age 20,70 ± 1,32 years). The findings were compared with similar indices in subjects with normal occlusion (mean age 21,3 ± 1,25 years). The index of orbicularis oris activity (ACTIV,%) was determined for each patient. A Student's t-test was used to analyze statistical difference between different groups.
  
  
  RESULTS
  patients having crowding of maxillary teeth showed greater activity of muscles of the upper lip during maximum voluntary clenching (АCTІV= -0,99±7,44%). Activity of the muscles of the lower lip in patients with crowding of mandibular teeth (АСTІV=20,52±4,22%) and crowding of maxillary and mandibular teeth (АСTІV=17,93±4,33%) is prevailing.
  
  
  CONCLUSIONS
  аctivity of the orbicularis oris in patients with malocclusion, complicated by dental crowding depend on clinical localization of crowding.
authors.affiliation: Higher Medical Educati onal Institution of Ukraine,"Ukrainian Medical Stomat ological Acade my", Poltava, Ukraine, e-mail: dmitrenko25@mail.ru.
authors.forename: Maryna I
authors.initials: MI
authors.lastname: Dmytrenko
authors.affiliation: Higher Medical Educati onal Institution of Ukraine,"Ukrainian Medical Stomat ological Acade my", Poltava, Ukraine.
authors.forename: Vira D
authors.initials: VD
authors.lastname: Kuroiedowa
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005152:Facial Muscles / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008046:Lip / Q000503:physiopathology*; D008297:Male; D008310:Malocclusion / Q000503:physiopathology*; D009119:Muscle Contraction; D055815:Young Adult
keywords: dental crowding; electromyographic indices; malocclusion; orbicularis oris