Estudo eletromiografico do padrão de co-ativação do musculo esternocleidomastoideo em diferentes movimentos mandibulares

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Although cervical muscles co-activation during jaw movements has been studied, this verification is stilllittle described in literature when are compared healthy subjects and patients with muscular dysfunction. The aim of this study was to verify by surface electromyography the bilateral co-activation of the sternocleidomastoid (SCM) muscle regarding to chewing muscles in healthy and bruxism volunteers. To record myoelectric signs, has been used a 16 channel signal conditioner with 12 bits dynamic band resolution (*Lynx Eletronics), Butterworth-type band pass filter (10,6-509 Hz) with gain of 100 times, and A/D converter board, placed inside of an Electrostatic Cage of Faraday. The myoelectric signs were displayed through by Aqdados Software installed in an Ibm-pc 486 DX2, that have showed simultaneous presentation of the used channels, each one with frequency of sampling of 1000 Hz. The signal was caught by simple active electrodes, formed by two rectangular and parallel silver bars, spaced for 10 mm. and fixed between it. The electrodes impedance of input was of 10G, 130 dB of CMRR and 2pF, with 100 times of gain. The materiaIs also used in this study were: reference electrode; adhesive tapes; Parafilm-M (American National Can?POT. TM?),metronome (Picollo-Winter) and milimetric ruler. The myoelectric signal was collected in three positions: a) chewing movements; b) clenching movements; c) isometric contraction of SCM muscles. The data has been evaluated statistically by ANOVA-repeated measures and impaired T tests, on accordance with the studied situation. The results have evidenced the presence of SCM coactivation in both groups and the analysis of RMS average values by chewing muscles have showed significant statistical differences between groups referring muscles, sides and situations analyzed, witch may be valid the criteria of sample inclusion adopted on this research. In healthy volunteers, the SCM co-activation was significantly fewer during chewing that in clenching, while that in bruxism subjects, these differences have not been verified. During clenching, a reduction of SCM co-activation referred as temporalis anterior muscle was proven, beyond the reduction of masseter muscle with an increase of temporalis anterior muscle activation has been observed in bruxism subjects. Comparing the values of SCM activation on jaw movements with its maximal isometric contractions, has been verified a significant reduction of muscular activity in right side on bruxism subjects. The results of this research, under those experimental conditions, have allowed concluding that the sternocleidomastoid coactivation during the jaw movements was verified in humans and that this seems to suffer influences from muscular alterations caused by bruxism. Thus, it is perceivable the necessity of accomplishment of more studies about this subject

ASSUNTO(S)

electromyography jaw movements sternocleidomastoid muscle bruxismo musculo temporal mastigação pescoço - musculos eletromiografia

ACESSO AO ARTIGO

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