Electromyographic chcracteristic of orbicularis oris in patients with dental crowding in permanent occlusion

Abstract

Introduction: Electromyographic indices were developed for complex analysis of functional condition of orbicularis oris. Aim: to study electromyographic indices of orbicularis oris in patients with dental crowding in permanent occlusion. Materials and 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: Activity of the orbicularis oris in patients with malocclusion, complicated by dental crowding depend on clinical localization of crowding.