Electromyography Assessment of Muscle Fatigue in Temporomandibuar Disorder Patients

Introduction Temporomandibuar disorder (TMD) is multifactor disease with unclear etiology, but some etiologic factors such as trauma, emotional stress, orthopedic instability and muscle hyperactivity appear to be very important in development of this disorder. The problems connected with TMD are located in masticatory muscles, jaw joints and in dentition. The most common complaint in TMD patients are functional disorders of masticatory muscles, specially the development of fatigue in these muscles. Purpose The intention of the study is to evaluate electromyographicaly the degree of muscle fatigue using fast Fourier transformation (FFT) of two elevator muscles, masseter and anterior temporal muscle. Material and methods The assessment of fatigue in masticatory muscles was done in two examined groups. One group consists of 23 patients with clinically diagnosed TMD, and the second group was 15 healthy volunteers. Every patient gets a same amount of chewing gym as a test food. They chew the chewing gym for a period of ten minutes and on the end of this period masseter and anterior temporal muscles were electromyographicaly examined. The electromyographic power spectrum (EPS) was obtained from every patient by surface electromyography. Surface electrodes were located right over the body of the examined muscle. Every EPS was then evaluated with FFT and the obtained results were statistically analyzed. Results Median frequency (MF) is useful parameter obtained by FFT and is in direct relation with the level of muscle fatigue. We noticed significantly (p