Abstract

COELHO-FERRAZ, M.J.P.; BERZIN, F.  and  AMORIM, C.. Electromyography evaluations of the masticator muscles during the maximum bite force. Rev Esp Cirug Oral y Maxilofac [online]. 2008, vol.30, n.6, pp.420-427. ISSN 2173-9161.

Healthy individuals were examined in terms of the pattern of activity of the masseter and temporal muscles in their anterior portion of both right and left sides, respectively, with the maximum bite force. The study consisted in seventeen adult volunteers with no sign of apparent temporomandibular dysfunction, of both genders, connected to the School of Dentistry of Piracicaba, with average age of 25 years old. The electromyography data were obtained, bilaterally, of the masseter, anterior portion of temporal and suprahyoid muscles in the postural and isometric positions. Were utilized surface passive electrodes for kids of Ag/AgCl, of circular format and dischargeable of Meditrace^® Kendall-LTP, model Chicopee MA01, attached to a pre-amplifier with gain of 20 times forming a differential circuit. The records of the electrical signs were captured by the equipment EMG-8OOC of EMG System of Brazil Ltd. of eight channels, with frequency of 2 KHz and 16 bits of resolution, digital filter with band pass of 20 to 500Hz. It was utilized also a pressurized transductor which consists of a pressurized rubber tube connected to a sensor element (MPX 5700) to obtain the maximum bite force. The statistic tests used were linear correlation, test t in pair and analysis of variance. Probability of p<0, 05 were significant considered statistically. The results showed a certain degree of muscular asymmetry for the masseter and anterior portion of temporal muscles that depended on the task performed or contraction level. The index of asymmetry was lower in the postural position than in the maximum bite force.

Keywords : Electromyography; Mandibular biomechanics.

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