Electromyographic analysis of the masseter and temporalis muscles and bite force in a patient treated by functional maxillary orthopedics: a case report

This case report evaluated electromyographic activity of the masseter and temporalis muscles and molar bite force, before and after with functional orthopedic. A 65 years woman presenting with orofacial pain symptoms, cervical tension, condyle subluxation and osteoarthrosis. The patient was diagnosed with temporomandibular dysfunction and treated with use of a Simões Network 9 modified type functional maxillary orthopedics appliance. The Myosystem BR1 apparatus was used to analyze the electromyographic activity of the masseter and temporalis muscles. The maximum molar bite force was measured with the digital dynamometer (Kratus). This study showed increased EMG activity of the masseter and temporalis muscles in postural conditions of mandible and molar bite force after 12 months of treatment. After twelve months of treatment, the patient had lack of pain symptoms as well as an improvement in the balance of the mastication muscles, as demonstrated by EMG activity and maximum molar bite force

Electromyographic analysis of masseter and temporal muscles in individuals with temporomandibular disorders before and after acupuncture treatment

O protocolo de atendimento aos indivíduos com dor orofacial, incluindo as disfunções temporomandibulares (DTMs), varia de acordo com o nível de comprometimento das estruturas, com a sintomatologia clínica e o tempo de instalação do problema. Tratamentos conservadores e reversíveis, tais como modificação de comportamento, terapia física, medicações e aparelhos ortopédicos funcionais são indicados para o cuidado inicial de quase todas as disfunções. As opções conservadoras de tratamento incluem: educação do paciente e autocuidados, agentes farmacológicos, terapia física e agentes físicos como a eletroterapia, o ultra-som e a acupuntura. Nos últimos anos, o interesse pelo uso da acupuntura na Odontologia tem aumentado, pois, a teoria do portão para controle da dor e o sistema de liberação de endorfinas, mecanismos fisiológicos envolvidos na acupuntura, têm sido demonstrados em pesquisas com animais e humanos. Com esta proposta de investigação científica pode-se comparar o que ocorre no processo da atividade elétrica dos músculos mastigadores em indivíduos portadores de disfunção temporomandibular muscular submetidos a tratamento com acupuntura. O objetivo deste trabalho é analisar e descrever as características funcionais dos músculos temporais e masseteres de pacientes portadores de disfunções temporomandibulares musculares e realizar um estudo comparativo da atividade eletromiográfica desses músculos e da força de mordida máxima, antes e após terapia com dez sessões de acupuntura, realizadas uma vez por semana. Os pontos de agulhamento da acupuntura foram IG4, E6, E7, B2, VB14, VB20, ID18, ID19, F3, E36, VB34, E44, R3, HN3. Para a análise eletromiográfica foi utilizado o eletromiógrafo Myosystem Br-1 e os dados coletados em repouso, apertamento dental, protrusão, lateralidade direita e esquerda, mastigação com parafilme e mastigação de amendoim e uva passa durante 10 segundos foram normalizados pela contração voluntária máxima (quatro segundos). A máxima força de mordida molar direita e esquerda foi coletada com o dinamômetro IDDK e todos os dados foram analisados por meio do teste-t com o programa estatístico SPSS (p ≤ 0,05). A atividade eletromiográfica dos músculos masseter e temporal diminuiu após o tratamento com acupuntura quando se avaliou a manutenção de posturas como repouso, protrusão e lateralidades direita e esquerda e o apertamento dental com parafilme, sendo significativo a nível de 0,05 para a situação de repouso. A mastigação habitual de amendoins e uvas passas também sofreu alteração no comportamento eletromiográfico, porém não significativo estatisticamente. A força de mordida máxima, embora não significativa estatisticamente, foi maior nos indivíduos após o tratamento com acupuntura. Ocorreu remissão completa da sintomatologia dolorosa para a maioria dos pacientes. Em conclusão, ocorreram alterações nos padrões de atividade elétrica dos músculos do sistema mastigatório em indivíduos portadores de disfunção temporomandibular muscular, após tratamento com acupuntura.The protocol for care to subjects with orofacial pain, including temporomandibular disorders (TMD), varies with the commitment degree of the structures, clinical symptoms and the time to install the problem. Conservative and reversible treatments, such as behavior changes, physical therapy, medicines and functional orthopedic devices are indicated for initial care in almost all dysfunctions. The options for conservative treatment include: patient education and self-care, pharmacological agents, physical therapy and physical agents such as electrotherapy, ultrasound and acupuncture. In recent years, the interest for the use of acupuncture in Dentistry has increased, because the gate control theory to pain control and the endorphin releasing system, physiological mechanisms involved in acupuncture, have been shown in animal and human research. With this scientific investigation purpose, it is possible to compare what happens in the electrical activity of muscles in individuals with temporomandibular muscle dysfunction undergoing treatment with acupuncture. The aim of this paper is to analyze and describe the functional features of temporal and masseter muscles in patients with muscular temporomandibular disorders and make a comparative study of the electromyographic activity of these muscles and the strength of maximal bite before and after therapy with ten acupuncture sessions conducted once a week. The needle location points were IG4, E6, E7, B2, VB14, VB20, ID18, ID19, F3, E36, VB34, E44, R3, HN3. The electromyography Myosystem Br-1 was used for electromyographic analysis and the data collected at rest, teeth clenching, protrusion, right and left laterality, parafilm chewing and peanuts and raisins chewing during ten seconds were normalized by the maximum voluntary contraction (four seconds). The right and left molar maximum bite strength was collected with the dynamometer IDDK and all data were analyzed with t test using statistical program SPSS (p≤0, 05). Masseter and temporal muscles electromyographic activity decreased after acupuncture treatment when posture maintenance such as rest, protrusion, right and left laterality and parafilm teeth clenching were evaluated, being significant at te level o 0,05 in the position of rest.The usual peanuts and grape passes chewing also underwent electromyographic changes, but not statistically significant. The maximum bite strength was bigger in subjects after acupuncture treatment although not statistically significant. There was complete remission of pain symptoms in most patients. In conclusion, there were changes in patterns of electrical activity of muscles of the masticatory system in individuals with temporomandibular muscle dysfunction after treatment with acupuncture

Electromyographic activity of masticatory muscles in women with osteoporosis

The purpose of this study was to analyze the electromyographic (EMG) activity and the maximal molar bite force in women diagnosed with osteoporosis in the maxillary and mandibular regions, considering the habits and conditions that lead to development of generalized skeletal bone loss, including on face bones, can disturb the functional harmony of the stomatognathic system. Twenty-seven women with mandibular and maxillary osteoporosis and 27 healthy controls volunteered to participate in the study. A 5-channel electromyographer was used. Muscle activity was evaluated by means of EMG recordings of the masticatory musculature (masseter and temporalis muscles, bilaterally) during the following clinical conditions: rest (5 s); right and left lateral excursions (5 s); protrusion (5 s); maximal dental clenching on Parafilm™ (4 s) and maximal voluntary contraction (4 s). This latter clinical condition was used as the normalization factor of the sample data. It was observed that individuals with osteoporosis presented greater EMG activity when maintaining mandible posture conditions and less activity during dental clenching and when obtaining maximal molar bite force. It may be concluded that facial osteoporosis can interfere on the patterns of masticatory muscle activation and maximal bite force of the stomatognathic system