Sınıf II bölüm 2 malokluzyonlu hastalarda kesici diş protrüzyonu sonrası ark morfolojisi, kas aktivitesi ve perioral basınçta meydana gelen değişikliklerin incelenmesi

Abstract

The aim of this study is to evaluate the changes in dentofacial structures, arch morphologies, orbicularis oris and masseter muscle activities and perioral pressures due to upper incisor proclination in mixed dentition who had Class

İİ division 2 malocclusion. Fort his purpose, 20 patients (with a mean age of 10,29 years) with Class II division 2 malocclusion were included in study group. 15 patients (with a mean age of 10,56 years) with Class I malocclusion were included in control group. In the study group, transpalatal arch were applied to the maxillary first molars and then upper incisors were proclined via protrusion utility arch. When the protrusion was completed, hawley retainer was applied for retention. Extraoral and intraoral photographs, dental casts, lateral cephalometric radiograph, perioral pressure and electromyographic measurements were obtained at the beginning of the treatment (T0), after protrusion (T1) and after retention period (T2) in study group. Furthermore, in control group, only perioral pressure and electromyographic measurements were obtained at T0, T1 and T2, because perioral measurements may be affected by ongoing growth. As a result of lateral cephalometric radiograph analysis, overjet increased while overbite and interincisal angle decreased. Both maxillary and mandibular incisors were proclined. Upper lip thickness increased at A point and decreased at vermilion while lower lip thickness increased at B point and decreased at vermilion. Both upper and lower lips were protruded according to the E plane. Nasolabial and mentolabial angles were increased. As a result of dental cast analysis, maxillary intercanine width, maxillary molar width, maxillary arch length, maxillary arch depth, mandibular intermolar width, mandibular arch length and mandibular arch depth increased. Upper

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lip pressure, lower lip pressure and interlabial pressure were changed over time, however there is no significance between study and control group. In study group, upper lip pressure and interlabial pressure decreased after protrusion, then increased after retention while lower lip pressure increased after protrusion, then decreased after retention. Orbicularis oris max-EMG, left masseter max-EMG and right masseter max-EMG were changed over time, however there is no significance between study and control group. In study group, orbicularis oris max-EMG increased after protrusion and then has remained stable after retention. Additionally, left and right masseter max-EMG decreased after protrusion and then increased after retention.