ABSTRACT
The treatment of a complex temporomandibular disorder (TMD), such as disk displacement with reduction (DDR) associated with arthralgia and myalgia, may depends on understanding the impairments in muscle function. The aim of this study was to investigate the behavior of the anterior temporalis, masseter and sternocleidomastoid muscles in the time and frequency domains during chewing in patients with chronic painful TMD-DDR using electromyographic (EMG) analysis. Thirty-three patients who met the diagnostic criteria for TMD and 32 volunteers without TMD (control group) underwent clinical examination, chewing pattern classification and EMG analysis. For the EMG analyses, the side of habitual unilateral chewing, as determined by the chewing pattern classification, was selected for recording; in cases of bilateral chewing, the recording side was randomly selected. The EMG-EMG coherence function and EMG-EMG transfer function (gain and phase) values were obtained at the first chewing frequency peak, and the working-side masseter signal was used as a reference in the analyses of the other muscles. Compared to the control group, the TMD group showed a longer chewing stroke duration (P = 0.01) as well as changes in the coactivation and coordination strategies of the jaw muscles, evidenced by greater relative energy expenditure (P< 0.01) and impaired differential recruitment (P< 0.05) and coherence (P< 0.01). Delays in peak and temporal asynchrony occurred in the jaw and neck muscles (P< 0.05). Patients with chronic painful TMD-DDR during chewing presented changes in the jaw and neck muscles, with more compromised function of the former, which are specific to chewing.
Subject(s)
Mastication , Temporomandibular Joint Disorders , Electromyography , Humans , Masseter Muscle , Neck Muscles , Temporal Muscle , Temporomandibular Joint Disorders/complicationsABSTRACT
ABSTRACT BACKGROUND AND OBJECTIVES: Assessing the possible interactions between the activity of masticatory muscles and quality of life and severity of the temporomandibular disorder can help clarify how changes in muscle activity can be associated with a chronic temporomandibular disorder in women. This study aimed to investigate the correlations between masticatory electrical activity during mandibular resting, maximum voluntary contraction, the severity of the temporomandibular disorder, and quality of life in women with chronic temporomandibular disorder and to compare these parameters with healthy asymptomatic controls. METHODS: Sixty women, 30 with temporomandibular disorder and 30 asymptomatic, participated in this case-control observational study. Diagnostic Criteria for Temporomandibular Disorder was used to identify the presence or absence of temporomandibular disorder. The SF-36 questionnaire was used to assess the quality of life in participants, and ProTMDmulti-part-II was applied to assess the severity of signs and symptoms of temporomandibular disorder. RESULTS: During jaw clenching, the masticatory activity of the right temporal and left masseter muscles, the symmetry of the masseter muscles, and anteroposterior coefficient were significantly smaller in the temporomandibular disorder group than in the asymptomatic group. Masticatory activity at rest, signs and symptoms of chronic temporomandibular disorder, and impairment of the quality of life were correlated using Spearman coefficient (p<0.05). CONCLUSION: Our results contribute to findings on the associations between the masticatory activity in chronic signs and symptoms of the temporomandibular disorder, impairment in quality of life, and differences in the masticatory activity during clenching in patients with temporomandibular disorder and controls.
RESUMO JUSTIFICATIVA E OBJETIVOS: Avaliar a possível interação entre a atividade dos músculos mastigatórios com a qualidade de vida e a gravidade da disfunção temporomandibular pode ajudar a esclarecer como as alterações na atividade muscular podem estar associadas a mulheres com disfunção temporomandibular crônica. O objetivo deste estudo foi avaliar a correlação entre atividade elétrica mastigatória durante o repouso mandibular, contração voluntária máxima, gravidade da disfunção temporomandibular e qualidade de vida em mulheres com disfunção temporomandibular crônica e comparar esses parâmetros com indivíduos assintomáticos (grupo controle). MÉTODOS: Sessenta mulheres, 30 com disfunção temporomandibular e 30 assintomáticas, participaram deste estudo observacional caso-controle. O instrumento critérios diagnósticos para disfunções temporomandibulares foi usado para detectar a presença ou ausência de disfunção temporomandibular. O questionário SF-36 foi usado para avaliar a qualidade de vida, e o ProDTMmulti parte II foi aplicado para avaliar a gravidade dos sinais e sintomas de disfunção temporomandibular. A atividade mastigatória durante o repouso mandibular e apertamento dentário foram medidos usando eletromiografia de superfície. RESULTADOS: Durante o apertamento dentário, a atividade do músculo masseter, temporal direito e esquerdo, simetria do masseter e coeficiente anteroposterior foram significativamente menores no grupo disfunção temporomandibular em comparação ao grupo assintomático. A atividade mastigatória em repouso, sinais e sintomas de disfunção temporomandibular crônica e os prejuízos na qualidade de vida foram correlacionados conforme determinado pelo coeficiente de Spearman (p<0,05). CONCLUSÃO: Os presentes achados contribuem para evidenciar as associações entre atividade mastigatória em sinais e sintomas crônicos de disfunção temporomandibular, comprometimento da qualidade de vida e diferenças na atividade mastigatória durante o apertamento dentário entre disfunção temporomandibular e grupo controle.
ABSTRACT
OBJECTIVES: To investigate whether chronic temporomandibular disorder (TMD) patients showed any changes in swallowing compared to a control group. Moreover, it was examined whether swallowing variables and a valid clinic measure of orofacial myofunctional status were associated. MATERIAL AND METHODS: Twenty-three patients with chronic TMD, diagnosed with disc displacement with reduction (DDR) and pain, according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and 27 healthy volunteers (control group) were compared. Surface electromyography (EMG) of the temporalis, masseter, sternocleidomastoid, and suprahyoid muscles was performed during swallowing tasks of thin liquid (10 and 15 mL) and spontaneous saliva. Data were normalized. RESULTS: Compared to the control group, TMD patients showed a prolonged duration of swallowing for liquid and saliva and required a longer time to reach the activity peak and half the integral. While the overall mean value of the relative peaks was similar for the groups, the suprahyoid peak was significantly lower in the TMD group during swallowing of liquid. Moreover, TMD patients recruited the jaw elevator muscles proportionally more than controls. The orofacial myofunctional status was moderately correlated with EMG parameters. CONCLUSION: Patients with chronic TMD showed temporal prolongation and changes in the relative activity of the muscles during the swallowing tasks. CLINICAL RELEVANCE: The present results contribute additional evidence regarding the reorganization of muscle activity in patients with chronic TMD.