The purpose of the study was to study and comparatively analyze the nature and degree of changes in electromyographic activity of the main and auxiliary chewing muscles in patients with temporomandibular joint dysfunction before and after the use of treatment with myorelaxant splints. Materials and methods. Five-year study on the basis of Stomatological Medical Center of Bogomolets National Medical University of patients with temporomandibular joint dysfunction (274 people) was conduscted. The general analysis provided 1024 detailed electromyograms before, after and at the stages of treatment of patients with temporomandibular joint dysfunction. Results and discussion. The results and conclusions of the analysis of the effectiveness of the treatment with the use of myorelaxant splints in the treatment of temporomandibular joint dysfunction indicate an increase in the quality of treatment of this pathology in patients and a reduction in the period of achievement of the result. The results obtained after 12 months indicate that the effectiveness of treatment of patients of control group I (with the lowest intensity of symptoms of temporomandibular joint dysfunction) reached 89.1±1.3%; control group II – up to 78.3±1.3%; control group III – 77.3±1.3%. In general, a study of the state of temporomandibular joint, complex clinical and paraclinic diagnosis, modern orthopedic treatment and prevention of musculoskeletal dysfunction of the temporomandibular joints were carried out. Based on the obtained data, the effectiveness of this algorithm of complex diagnosis, treatment and prevention of musculoskeletal dysfunction of temporomandibular joint was developed, clinically implemented and evaluated. Also, the data obtained as a result of the study by the authors were the basis for finding and correcting new methods and algorithms for diagnosing and treating pathology. The original author's concept of the pathogenesis of muscular-articular dysfunction of temporomandibular joint, used in the study and scientifically substantiated by the authors, united all existing theories of the development of this disease. The multifactorial analysis revealed an increase (p <0.001) of the risk of not achieving the effect of treatment by reducing pain syndrome with an increase in scores on the Bayers scale before treatment, odds ratio = 1.6 (95% of BI 1.4–1.9) for each point of growth score (when standardizing on three other risk factors). An increase (p=0.002) of the risk of not achieving the effect of treatment by reducing pain syndrome with an increase in the asymmetry of the indicator J_MM_A_max, Index Bayers (visual analogue scale) = 1.08 (95% BI 1.03–1.12) for each point exceeding the value of the indicator for the left half above the right (when standardizing on three other risk factors). Also, an increase (p= 0.049) of the risk of not achieving the effect of treatment for a decrease in pain syndrome with an increase in the asymmetry of the J_MM_A_mean indicator, odds ratio = 1.28 (95% of BI 1.00–1.65) for each point exceeding the value of the indicator for the left side above the right side (when standardizing on three other risk factors) was found. Conclusion. Such a thorough approach to the implemented model of diagnosis and treatment of patients with temporomandibular joint dysfunction and a synchronized complex of studies and treatment of this pathology, developed in accordance with it, provided an opportunity to assess qualitative and quantitative changes in the link of the chewing apparatus and the central link of the corresponding functional biosystem that ensure the formation and implementation of the main functions of the temporomandibular joint
