title: Electromyographical analysis of the masseter muscle in dentulous and partially toothless patients with temporomandibular joint disorders.
abstract: This study had as objective to analyze with computerized electromyography the masseter muscles bilaterally in twenty individuals with temporomandibular joint dysfunction (DTM), being: the group I consisting of ten individuals with complete dentition and group II constituted by ten individuals with posterior dental absences; comparing nine clinical activities: rest before and after exercises, maximum habitual intercuspation (MIH), right and left laterality, forced centric occlusion, protrusion, bilateral molar bite and chewing. It was utilized the Electromyography K6I-Myotronics, with eight canals and surface silver electrodes. By means of the results analysis, we verified significant differences between the groups (p < 0.01), being group I, presented greater electromyographic activity (32.98 microvolts), than the group II (22.31 microvolts), suggesting that this individuals presented low muscular activity. The interaction between the groups and the clinical activities was significant (p < 0.01), as well as between the groups, clinical activities and muscles (p < 0.05). To clarify which amongst the relative averages the clinical activities were different, calculated the critical value of Tukey, being that rest before and after exercises, MIH, right and left laterality, presented averages with similar distributions, with values below of the values of Tukey, as well as forced centric occlusion, protrusion, bilateral molar bite and chewing presented higher values than Tukey. Based on this research's data, we concluded that the electromyographical analysis of the masseter muscles in Individuals with TMD, dentulous and with dental absence showed that individuals with TMD, dentulous or not, presented elevated muscular activity in rest position and individuals with TMD, dentulous, presented higher electromyographical activity than the individuals with TMD and lacking posterior teeth.
authors.affiliation: Department, Faculty of Dentistry of Ribeirão Preto of the University of São Paulo (FORP-USP), Brasil.
authors.forename: M A M Rodrigues
authors.initials: MA
authors.lastname: da Silva
authors.forename: J P M
authors.initials: JP
authors.lastname: Issa
authors.forename: M
authors.initials: M
authors.lastname: Vitti
authors.forename: A M Rodrigues
authors.initials: AM
authors.lastname: da Silva
authors.forename: M
authors.initials: M
authors.lastname: Semprini
authors.forename: S C H
authors.initials: SC
authors.lastname: Regalo
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003766:Dental Occlusion; D004576:Electromyography; D005260:Female; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D008406:Masseter Muscle / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology; D012146:Rest / Q000502:physiology; D013705:Temporomandibular Joint Disorders / Q000150:complications* / Q000503:physiopathology*