Morfofunctional study of the medial superior region of the orbicular muscle of the mouth in children with Angle Class II, division 1 and with respiratory manner predominantly nasal or buccal

Felipe FRONZA, Romeu Valério KOWALSKI, Roberto Hideo SHIMIZU, Douver MICHELON, Orlando Motohiro TANAKA

The chronicle buccal breathing is deined as a habitual breathing by the mouth, instead of accomplished by the nose, due to the elevated nasal resistance, carrying soft tissues and adjacent skeletal structures adaptations in the sense of keeping the pharynx space suficiently open. These adaptations results in modiications in the postural position of the jaw, making change to the appearance of the malocclusion. We present a study where was accomplished a morfofuntional evaluation of the medial superior region of the orbicular muscle of the mouth, investigating possible correlations with the buccal breathing. The sample consisted of 50 brazilian children, six to nine years old, 25 boys and 25 girls, with Angle Class II, division 1 malocclusion and respiratory mode predominantly nasal or buccal. The superior lip form was studied by means of lineal height and thickness of proile radiography. The functional evaluation consisted on eletromiographyc analysis of the orbicular muscle of the mouth, accomplished during the repose situation and in more 21 lip-mandibular actions, by means of surface electrodes. The collected data were submitted to the descriptive statistics, test t (Student) for independent samples and test F for two variances. The results pointed that there was no statistically signiicant difference among both groups studied regarding superior lip form, as well as for the function, and there is no correlation among morphology and functional behavior of the medial superior region of the orbicular muscle of the mouth for this evaluated sample, regardless of the respiratory way.

Keywords: Mouth breathing. Upper lip. Orbicular muscle. Malocclusion. Electromiography.

Sunday, April 28, 2024 13:44