title: Asymmetric activation of temporalis, masseter, and sternocleidomastoid muscles in temporomandibular disorder patients.
abstract: The aim of this study was to analyze the symmetry of the electromyographic (EMG) activity of the temporalis, masseter, and sternocleidomastoid (SCM) muscles in volunteers divided into a control group and a temporomandibular disorder (TMD) group. The surface EMG recordings were made during mandibular rest position, maximal intercuspal position, and during the chewing cycle. Normalized EMG waves of paired muscles were compared by computing a percentage overlapping coefficient (POC). The difference between the groups and between the static and dynamic clenching tests was analyzed through repeated measures, ANOVA. Symmetry of the temporalis, masseter, and SCM muscles activity was smaller in the TMD group compared to the control group. The mandibular postures were also significantly different among themselves. The asymmetric activation of jaw and neck muscles was interpreted as a compensatory strategy to achieve stability for the mandibular and cervical systems during masticatory function.
authors.affiliation: Department of Prevention, Assessment, and Rehabilitation of Santa Catarina State Development University. d2lgkr@udesc.br
authors.forename: Lilian Gerdi Kittel
authors.initials: LG
authors.lastname: Ries
authors.forename: Marcelo Correa
authors.initials: MC
authors.lastname: Alves
authors.forename: Fausto
authors.initials: F
authors.lastname: Bérzin
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography / Q000379:methods; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008406:Masseter Muscle / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology; D011187:Posture / Q000502:physiology; D013703:Temporal Muscle / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000150:complications*