Comparison of masticatory muscle activity in children and adolescents with distal and mesial occlusion

Abstract

The growth and harmonious development of the structures of the maxillofacial region depend on the physiological functioning of the muscles of the orofacial zone. Moss's theory of functional matrices, established in 1972, is a clear confirmation of the influence of the soft tissue component on the formation of the human dentition and jaw system. Violation of the tone of the masticatory muscles leads, as a rule, to functional disorders, therefore, most patients with distal occlusion have underdevelopment of the lower jaw and its distal location. The aim of the study was to improve the efficiency of diagnosis and treatment of patients with malocclusion in the sagittal direction based on the determination of indicators of masticatory muscle activity in children and adolescents in the age period 9—12. Analysis of indicators of the functional state of the orofacial region in children with malocclusion in the sagittal direction makes it possible to understand additional risk factors, in addition to the occlusion itself, for the development of mesial or distal occlusion, thereby achieving more effective diagnosis and stable treatment. Materials and methods. 50 children aged 9—12 years, boys and girls with bite pathology in the sagittal direction, were examined. The patients were divided into two groups: group 1 — children with distal and group 2 — children with mesial occlusion. Clinical examination was carried out using a dental kit, a standard intraoral photo protocol and a photo of the face were also used. The functional activity of masticatory muscles was studied using surface electromyography. Electromyographic tests were carried out in a state of physiological rest. The bioelectrical activity of each muscle separately and the total activity of all 4 IMPACT masticatory muscles were studied. Results. When studying the bioelectrical potentials of the masticatory muscles in patients with distal bite, it was found that the temporal muscles had higher values than the actual masticatory muscles. The average ratio of temporalis muscles to masseters was 1:0.7. The total activity of all 4 IMPACT muscles was 961 V. While patients with mesial occlusion had opposite indicators. The bioelectric potentials of the temporal muscles were lower in comparison with the masticatory muscles proper. The average ratio of temporal muscles to masticatory muscles was 0.6:1. The total activity of all 4 IMPACT muscles in this case was 543 V.