Functional activity of the maxillofacial region muscles in children with arthrogryposis multiple congenita

BACKGROUND: Disorders of the maxillofacial region in children with аrthrogryposis multiplex congenita can be congenital or occur as secondary changes. The lower jaw and associated muscles play important roles in the functioning and development of the maxillofacial region. In children with аrthrogryposis multiplex congenita, the functional activity of the muscles of the maxillofacial region has not been studied. AIM: To estimate the functional activity of the muscles of the maxillofacial region in children with аrthrogryposis multiplex congenita. MATERIALS AND METHODS: Surface electromyography was used to examine the masticatory and facial muscles of 47 children aged 317 years with arthrogryposis (main group) and 20 healthy children with orthognathic bite (control group). The main and control groups were examined by a dentist and had not previously received orthodontic treatment. The bioelectric activities of the temporalis and masseter muscles on the right and left sides were simultaneously registered at rest and during functional tests (opening of the mouth, moving the lower jaw forward, jaw compression, and chewing). The average activity amplitudes were taken into account, and asymmetry coefficients were calculated. The obtained data are statistically processed. RESULTS: Electromyography results, according to different functional tests, revealed disorders in 65%88% of children with аrthrogryposis multiplex congenita. In all samples, the tonic activity of the masticatory muscles increased at rest, the amplitude of the activity of masseter and temporalis muscles decreased, signs of an imbalance of the masticatory muscles such as the hyperactivation of the temporalis muscle compared with the masseter muscle with jaw compression and chewing were noted, and muscle asymmetry indices increased. The frequency and degree of functional muscle disorders prevailed in children with deciduous and temporary occlusion. CONCLUSIONS: Arthrogryposis multiplex congenita in children is characterized by a high frequency of impaired functional activity of the muscles of the maxillofacial region, which can negatively affect bite formation, chewing function, and articulation.