Analise eletromiografica dos musculos orbicular da boca e mentoniano, em individuos portadores de maloclusão classe II divisão 1 de Angle




The function and the level of activity of the orbicularis oris (superior and inferior), and of the mentalis muscles were verified electromyographicaly in resting position and in several movements and carried out in 18 children aging 8 to 12 years, divided into 3 groups: one with normal occlusion, and two, with Angle s class II division 1, with atypical swallowing and/or incompetent lips, who had received no orthodontic treatment. It was observed that, in resting position with the lips separated, there was no activity in any of the muscles. When there was a contact of the lips, action potentials were recorded in the muscles studied, in those individuaIs with incompetent lips. In the movements of sucking through a straw, a pacifier, and the thumb, there were no differences among the groups. The incompetent lips group presented very strong muscle activity of the orbicularis oris inferior and mentalis in the movement of sucking a-candy straw. In the deglutition of saliva, the orbicularis oris presented weak activity, and the mentalis, moderate. In the deglutition of water, the mentalis presented very strong activity, whereas, the orbicularis oris superior and inferior, presented moderate and strong acitivities, respectively. Blowing through a straw, and the insufflation of the cheeks, required strong activity of the orbicularis oris and mentalis muscles, in both groups of malocclusion. In these same groups, in the projection and in the compression of the lips, it was noticed a great activity of the orbicularis oris inferior; and in the compression of the lips against the teeth, the greater activity was of the orbicularis oris superior. These findings showed that the muscles studied presented a greater activity in subjects exhibiting incompetent lips, malocclusions and atypical swallowing, than in those considered clinically normais


eletromiografia desarmonia oclusal ortodontia