title: Masticatory muscle activity in children with a skeletal or dentoalveolar open bite.
abstract: The aim of this study was to compare the electromyographic (EMG) characteristics of masticatory muscles in children with either a skeletal or dentoalveolar open bite, compared with a control group (CG). Forty-five children (31 boys and 14 girls), aged 6-11 years, were included in the study, 15 with a skeletal anterior open bite (SAOB), 15 with a dentoalveolar anterior open bite (DAOB), and 15 with a normal occlusion (CG), defined by clinical evaluation and lateral cephalograms. EMG recordings of the temporal and masseter muscles were performed under maximal voluntary clenching and during chewing. Analysis of variance was used for inter-group analysis, followed by the Tukey post hoc test. A Student's t-test for paired data was used for intra-group analysis. There were statistically significant differences among the three groups (P < 0.05), with the mean EMG being highest in the CG and lowest in children with a SAOB. The percentage EMG activity during chewing in relation to that during maximal voluntary clenching was more than 100 per cent in the SAOB group. The CG and DAOB groups presented higher EMG activity during clenching compared with chewing (P < 0.001), as well as a greater difference between tasks. In the SAOB group, the neuromuscular system appeared to have a lower capacity to produce EMG activity according to the task, while that in the DAOB group suggests that their functional capacity during growth should also be carefully observed.
authors.affiliation: Department of Otorhinolaryngology, Faculty of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Tatiana dos Santos
authors.initials: Tdos S
authors.lastname: Ciccone de Faria
authors.forename: Simone Cecilio
authors.initials: SC
authors.lastname: Hallak Regalo
authors.forename: Adilson
authors.initials: A
authors.lastname: Thomazinho
authors.forename: Mathias
authors.initials: M
authors.lastname: Vitti
authors.forename: Cláudia Maria
authors.initials: CM
authors.lastname: de Felício
mesh_terms: D016022:Case-Control Studies; D002508:Cephalometry; D002638:Chewing Gum; D002648:Child; D004576:Electromyography; D005260:Female; D005502:Food; D006801:Humans; D008297:Male; D008334:Mandible / Q000473:pathology; D008406:Masseter Muscle / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D009295:Nasal Bone / Q000473:pathology; D024343:Open Bite / Q000145:classification / Q000503:physiopathology*; D019291:Skull Base / Q000473:pathology; D013100:Sphenoid Bone / Q000473:pathology; D013703:Temporal Muscle / Q000503:physiopathology*
chemical_list: D002638:Chewing Gum