Masticatory muscle activity in individuals with temporomandibular disorder

Abstract

Introduction. Temporomandibular disorders (TMD), as a collective term that covers a number of clinical problems related to the masticatory muscles, occlusion, and structural components of the TMJ. Diagnostic evaluation of the muscles activity is an integral part in the planning and set of measures for rehabilitation of dental patients. Electromyography is one of the methods of objective, minimally invasive muscle examination instrumental and highly informative method of functional diagnostics of muscles, namely recording of biopotentials of muscle fibers and activity of their motor units. The aim. The aim of our study was to investigate features related to EMG-activity of masticatory muscles in subjects with TMD. Materials and methods. The study comprised 22 patients with clinical symptoms of TMD. The average age of the subjects was 29.3 ± 4.4 years. Malocclusion was evaluated according to Angle classification, TMD – according to the Research Diagnostic Criteria (RDC/TMD). Registration of EMG-activity of masseter and anterior temporalis muscles was performed during maximum voluntary clenching, clenching on the right and left sides. Results. Normal activity of the masticatory muscles is characterized by symmetrical and EMG-activity of the masticatory muscles on the left and right sides. EMG-activity of masticatory muscles in subjects with TMD are characterized by: 1) increased values of EMG-activity of temporal and masseter muscles; 2) disproportional and asymmetric muscle work of the masticatory muscles on the right and left sides. Conclusion. Features of masticatory muscles activity in individuals with Angle Class I malocclusion and TMD were found.