Correlação eletromiografica e cefalometrica da biomecanica mandibular com o movimento mastigatorio predominante / Etectromyographic correlation and cephalometric of mandibular biomechanical with the predominant masticatory movement

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The study of the craniomandibular biomechanics is related to the system of predominant lever and of the relation between function and mechanically induced deformations. This study has the purpose of evaluating the chewing muscular dynamics and correlating the chewing movement side that is more vertical and/or more horizontal set up by the photomeasurement Planas Masticatory Functional Angle (MFA) to the muscular activity behavior, shown in the surface electromyography and in the radiographic images. Seventeen people of both sex, medium aged about 25, were selected, white skin and presenting Class I of Angle without apparent sign and symptom. The panoramic radiography and telerradiography in lateral position and surface electromyography were made. The acquisition of radiographic images followed the rules established by the Piracicaba Dental School (UNICAMP). The electromiographic data were obtained bilaterally from the masseter muscles, anterior temporal portion and supra-hyoids at the postural position and isometric position. Medtrace® passive bipolar surface electrodes were used coppled to a pre-amplifier, forming a circuit corresponding to a differential circuit. The registrations of the electric signals were caught by EMG- 800C equipment of Brazil EMG System Ltda with eigth channels, sample frequency of 2 KH and 16 bits resolution, digital filter with a band pass of 20-500 Hz. A pressurized transductor was used, which consists of a pressurized rubber tube connected to a sensor (MPX 5700)* to obtain maximum biting force. A mandibular goniometer of the EMG System of Brazil was used to measure the opening size. A comparison and correlation between the groups with MFA <5° and MFA>5° through “t” Student or a Man- Whitney test according to the normality or not of the distribution, respectively. The results have shown important differences between the groups with MFA <5° and MFA >5° but without sexual disformity to the biting force measurements (38,70 ±, 10,88 and 27,28 ±11,40), for the maximum opening. (40,04 ± 11,82 and 26.86± 11,70) and masseter muscle isometric (174, 16± 49,67 and 116, 41± 51,11). A strong correlation between the masseter muscles to the biting force (r = 0,63 p =0,0001) occurred for the groups with MFA >5°. On the Hyoid triangle, for both groups, the vertical and angular behavior of the hyoid bone represented by H–H’ and PHA showed important correlations to the mandibular dynamics recorded on the panoramic radiography. All these results indicate to a strong relationship between the aspects anatomic physiological with asymmetric mandibular function.

ASSUNTO(S)

eletromiografia cefalometria cephalometry biomecanica mandible electromyography mandibula biomechanics

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