Computed tomography evaluation of alterations in the masticator space due to invasion by malignant head and neck neoplasms / Avaliação das alterações do espaço mastigador decorrentes de invasão de neoplasias malignas de cabeça e pescoço por meio de tomografia computadorizada

Abstract Objective: To evaluate alterations in the masticator space due to the dissemination of malignant neoplasms originating from the tonsillar fossa, retromolar trigone, maxillary sinus, or nasopharynx, using computed tomography (CT), as well as to correlate the presence of trismus with the CT findings and the dimensions of the tumor. Materials and Methods: We evaluated the medical records of 65 patients with malignant tumors in the regions described. The images were analyzed by two physician examiners, working independently, who were blinded to the clinical data. In the evaluation of the masticator space, the following parameters were considered: symmetry with the contralateral space; obliteration of the fat plane, retromolar trigone, or pharyngeal space; edema/atrophy of the medial or lateral pterygoid muscles; and destruction of the mandibular ramus. Results: Obliteration of the fat plane was found in 69.2% of the patients. Asymmetry, edema/atrophy, and bone destruction were detected in 27.7%, 26.2%, and 20.0% of the patients, respectively. Trismus was identified in 15.4% of the patients. Of the patients with trismus, 90.0% had stage T4 tumors, compared with only 43.8% of those without trismus. Trismus was 11.6 times more common among the patients with stage T4 tumors than among those with lower-stage tumors. Neoplasms of the tonsillar fossa and retromolar trigone collectively accounted for 95.0% of the cases. The CT scans showed edema/atrophy of the pterygoid muscles in 60.0% of the patients with trismus and in 21.8% of those without. An association was observed between T4 tumor stage and edema/atrophy of the pterygoid muscles. In addition, the risk of trismus was 5.4 times higher among the patients with stage T4 tumors. Conclusion: In our patient sample, the most common finding was obliteration of the fat plane, followed by asymmetry and edema/atrophy. Most of the patients with T4 tumors had trismus, together with edema/atrophy of the pterygoid muscles.

Resumo Objetivo: Avaliar, por meio de tomografia computadorizada, alterações do espaço mastigador (EM) decorrentes de disseminação de neoplasias malignas originárias da loja tonsilar, trígono retromolar, seio maxilar e nasofaringe, e correlacionar presença de trismo com achados tomográficos e dimensões do tumor. Materiais e Métodos: Foram selecionados prontuários de 65 pacientes portadores de tumores malignos nas regiões descritas. A análise das imagens foi realizada por dois examinadores médicos, separadamente, sem o conhecimento das informações clínicas. Na avaliação do EM, foram considerados: simetria com o EM contralateral; obliteração do plano gorduroso, do trígono retromolar e do espaço faríngeo; edema e/ou atrofia dos músculos pterigóideos medial e lateral; destruição do ramo da mandíbula. Resultados: Foram observados obliteração do plano gorduroso em 69,2% dos pacientes, assimetria em 27,7%, espessamento/atrofia em 26,2% e destruição óssea em 20,0%. Presença de trismo foi encontrada em 15,4% dos pacientes. Na associação entre dimensão do tumor e trismo, foram observados trismo em 90,0% dos tumores em estágio T4, enquanto a porcentagem de tumores em estágio T4 sem trismo foi de 43,8%. Pacientes com tumores T4 apresentaram 11,6 vezes mais trismo que os dos demais estágios. Neoplasias da loja tonsilar e trígono retromolar perfizeram 95,0% dos casos. Em 60,0% dos pacientes com trismo havia edema e/ou atrofia dos músculos pterigóideos na tomografia computadorizada e em 21,8% nos sem trismo. Observou-se associação entre tumores T4 e edema e/ou atrofia dos músculos pterigóideos e 5,4 vezes mais chance de apresentarem trismo. Conclusão: A maioria dos pacientes apresentou obliteração do plano gorduroso, seguido de assimetria e espessamento/atrofia. O trismo estava presente na maioria dos pacientes T4 com espessamento/atrofia dos músculos pterigóideos.

The hyperboloid device does not affect masticatory electromyographic activity during jaw movements in individuals with temporomandibular joint disorders / A hiperboloide não influencia a atividade eletromiográfica dos músculos mastigatórios durante movimentos mandibulares em indivíduos com disturbiotemporomandibular

Abstract Introduction The hyperboloid is a masticatory device made of silicone with an hourglass (hyperbolic) shape that has been used as an aid to jaw functional orthopedic therapy. Objective To evaluate whether the hyperboloid device affects electromyographic (EMG) activity of the masticatory muscles during jaw movements in individuals with temporomandibular joint disorders (TMD) compared to controls. Methods The study sample consisted of 49 participants divided into two groups: mild, moderate and severe TMD (TMD group; n = 25) and a control group (n = 24). We evaluated EMG activities of temporal and masseter muscles bilaterally during jaw protraction and retraction, and left and right lateralization with and without the use of the hyperboloid device. Statistical analyses were performed using two-way ANOVA with two factors: group (healthy and TMD) and situation (with or without the use of the hyperboloid). Results We found higher EMG activity in the left temporal in the TMD group and no difference in EMG activities with the use of the hyperboloid device. Conclusion The use of the hyperboloid device did not affect EMG activity of the muscles evaluated in the groups studied. We found higher EMG activity of the left temporal muscle in participants with TMD. Long-term randomized studies should be conducted in individuals with TMD to investigate the effects of functional orthopedic therapy using the hyperboloid device with visual and quantitative feedback.

Resumo Introdução O hiperboloide é um aparelho mastigatório feito de silicone com formato de ampulheta (hiperbólica), que tem sido utilizado como auxiliar na terapia ortopédica funcional da mandíbula. Objetivo Avaliar se o dispositivo hiperbolóide afeta a atividade eletromiográfica (EMG) dos músculos mastigató-rios durante os movimentos mandibulares em indivíduos com disfunção da articulação temporomandibular (DTM) em comparação com controles. Métodos A amostra do estudo foi composta por 49 participantes divididos em dois grupos: DTM leve, moderada e severa (grupo DTM; n = 25) e grupo controle (n = 24). Avaliaram-se as atividades EMG dos múscu-los temporal e masseter bilateralmente durante a protração e retração da mandíbula e lateralização esquerda e direita com e sem o uso do dispositivo hiperboloide. As análises estatísticas foram realizadas por ANOVA two-way com dois fatores: grupo (saudável e DTM) e situação (com ou sem uso do hiperbolóide). Resultados Encontramos maior atividade EMG no temporal esquerdo no grupo DTM e nenhuma diferença nas atividades EMG com o uso do dispositivo hiperboloide. Conclusão O uso do hiperboloide não afetou a atividade EMG dos músculos avaliados nos grupos estudados. Encontramos maior atividade EMG do músculo temporal esquerdo em participantes com DTM. Estudos randomizados de longo prazo devem ser conduzidos em indivíduos com DTM para investigar os efeitos da terapia ortopédica funcional usando o dispositivo hiperbolóide com feedback visual e quantitativo.

Influence of Breathing Modes and Facial Growth Patterns on Electromyographic Fatigue of Masticatory Muscles in Children

Abstract Introduction Changes in breathing patterns affect the harmonious development of the structures of the craniofacial system, leading to changes in posture, occlusion, and facial growth patterns. However, little is known about how these changes influence the muscle contraction patterns, either at rest or while functioning, and either in a normal or unbalanced condition. Objective To study the masseter and anterior temporal muscles fatigue during mastication in nasal- and mouth-breathing children, also considering their facial growth patterns. Methods: A total of 70 children aged 6 to 12 years old who met the study criteria were assessed. Speech-language-hearing, otorhinolaryngologic, and cephalometric assessments were performed to divide them into groups. In the electromyographic assessment, the children were asked to chew gum following a metronome until they felt fatigued. The median frequency of the muscles was analyzed at 15, 30, 45, and 60seconds of mastication.The reported time of fatigue perception was recorded. The data were analyzed with analysis of variance (ANOVA) and the Kruskal-Wallis and the Mann-Whitney U tests. Results There were no median frequency decrease patterns nor differences in the myoelectric manifestations and reported time of fatigue between the groups. Conclusion The masticatory muscles did not reveal fatigue in the electromyographic analysis; however, the fatigue time was reported, despite the absence of physiological fatigue. The breathing mode, the facial growth pattern, and the association between them did not interfere with the behavior of the median frequency of the electromyographic signal and the fatigue time perception.

Efecto de la dibucaína sobre la SERCA del músculo pterigoideo interno / Drug action of dibucaine on the SERCA from medial pterygoid muscle

Objetivo: Determinar el efecto del anestésico local di-bucaína sobre las principales isoformas de la SERCA (calcio ATPasa de retículo sarco-endoplásmico) pre-sentes en músculo pterigoideo interno. Métodos: Se aislaron por centrifugación diferencial membranas de retículo sarcoplásmico de pterigoideo interno de conejo neozelandés macho (n=5). Se separaron las isoformas SERCA1a, 2a y 2b por cromatografía de afinidad. Se determinó in vitro la actividad enzimá-tica en presencia de diferentes concentraciones de dibucaína (0-90 mM) por el método de Fiske y Subba-row, realizando 5 experimentos por duplicado y en paralelo para cada isoforma. Se calculó la media y ES de la CI50 (mM) del anestésico para cada isofor-ma y éstas se compararon por ANOVA de una vía (p<0,05), y prueba Student-Newman-Keuls de com-paraciones múltiples. Resultados: Dibucaína inhibió la actividad enzimática en función de su concentra-ción en las tres isoformas en estudio. Las CI50 fueron: SERCA1a 20,02 ± 0,64 mM, SERCA2a 15,03 ± 0,52 mM y SERCA2b 16,00 ± 0,51 mM y resultaron signi-ficativamente diferentes (F2,27 = 11,08, p<0,001). La prueba post hoc identificó diferencias significativas entre SERCA1a y 2a, 1a y 2b. El efecto inhibitorio re-sultó significativamente mayor sobre las isoformas 2a y 2b, cuya presencia es sustancialmente mayor en músculos masticadores. Conclusión: La dibucaína inhibe a la SERCA de pterigoideo interno a concen-traciones menores que las usadas en clínica médica (29 mM). Es un anestésico local con potencial efecto miotóxico derivado de la inhibición de la SERCA (AU)

Aim: To test the effect of the local anesthetic dibu-caine on the main isoforms of the SERCA (sarco-endosplasmic reticulum calcium-ATPase) in medial pterygoid muscle. Methods: Sarcoplasmic reticulum membranes from male New Zealand rabbits (n=5) were isolated from medial pterygoid muscle by ul-tracentrifugation. The isoforms SERCA1a, 2a and 2b were separated using high affinity chromatography. In vitro enzymatic activity determinations were per-formed in the presence of different dibucaine con-centrations (0-90 mM) using the colorimetric method described by Fiske & Subbarow. Five assays in dupli-cate and run in parallel were performed for each of the isoforms. Mean and SEM of the IC50 (mM) for the effect of the anesthetic on each isoform were calcu-lated and compared by one-way ANOVA (p<0.05), and Student-Newman-Keuls multiple comparisons test. Results: Dibucaine inhibited the enzymatic activity in a concentration-dependent manner for the three studied isoforms. The IC50 values were: SERCA1a 20.02 ± 0.64 mM, SERCA2a 15.03 ± 0.52 mM and SER-CA2b 16.00 ± 0.51 mM. The values were significantly different (F2.27 = 11.08, p<0.001). The post hoc test revealed significant differences between SERCA1a and 2a, 1a and 2b. The inhibitory effect was signifi-cantly higher on 2a and 2b isoforms, whose presence is substantially higher in masticatory muscles. Con-clusion: Dibucaine inhibits SERCA in medial pterygoid muscle at concentrations lower than those used in clinical medicine (29 mM). It is a potentially myotoxic local anesthetic whose toxic effect may derive from SERCA inhibition (AU)

Response of masticatory muscles to treatment with orthodontic aligners: a preliminary prospective longitudinal study

ABSTRACT Introduction: The emergence of orthodontic aligners has provided an aesthetic and comfortable option for orthodontic treatment. However, the encapsulated design of the aligners can influence the masticatory muscles, and might compromise safe treatment. Objective: This preliminary longitudinal study aimed to investigate whether the use of orthodontic aligners affects the biting force and myoelectric activity of the superficial masseter and anterior temporal muscles. Methods: Ten subjects participated in the study and underwent treatment during an 8-month follow-up period. The root mean square (RMS), the median power frequency (MPF) of the surface electromyography (sEMG) signals, and the biting force (kgf) were recorded and normalized relative to the pretreatment condition. The data were analyzed by repeated-measure analysis of variance (ANOVA), with the significance level set at 5%. Results: Both the superficial masseter and the anterior temporal muscles presented an increase in sEMG signal activity during the treatment, with a marked increase in the latter compared to the former (p<0.05). Moreover, a significant decrease in bite force was evidenced (p<0.05). Conclusions: This preliminary study observed that the orthodontic aligners affected the muscle recruitment pattern of masticatory muscles, and reduced biting performance during the 8-month follow-up period.

RESUMO Introdução: O surgimento dos alinhadores ortodônticos tem proporcionado uma opção estética e confortável para o tratamento ortodôntico. No entanto, o design encapsulado dos alinhadores pode influenciar os músculos mastigatórios e comprometer a segurança do tratamento. Objetivo: Este estudo longitudinal preliminar teve como objetivo investigar se o uso de alinhadores ortodônticos afeta a força de mordida e a atividade mioelétrica dos músculos masseter superficial e temporal anterior. Métodos: Dez indivíduos participaram do estudo e foram submetidos a tratamento durante um período de acompanhamento de 8 meses. A raiz quadrada média (RMS), a frequência mediana de potência (FMP) dos sinais de superfície da eletromiografia (sEMG) e a força de mordida (kgf) foram registradas e normalizadas em relação à condição de pré-tratamento. Os dados foram analisados por análise de variância para medidas repetidas (ANOVA), com nível de significância estabelecido em 5%. Resultados: Tanto o masseter superficial quanto o temporal anterior apresentaram aumento da atividade do sinal sEMG durante o tratamento, com aumento acentuado desse último em comparação ao primeiro (p<0,05). Além disso, foi evidenciada uma diminuição significativa da força de mordida (p<0,05). Conclusões: Esse estudo preliminar observou que os alinhadores ortodônticos afetaram o padrão de recrutamento muscular dos músculos mastigatórios e reduziram o desempenho da mordida durante o período de acompanhamento de oito meses.

Evaluating the use of wearables in the masseter and temporal muscles: a scoping review protocol / Avaliação do uso de tecnologias vestíveis nos músculos masseter e temporal: um protocolo de revisão de escopo

ABSTRACT Purpose: to develop a scoping review protocol that seeks to identify which procedures and for what purpose wearables available in the literature are being used on the masseter and temporal muscles. Methods: the approach recommended by The Joanna Briggs Institute and the PRISMA-P guidelines, will follow. Databases to be searched include PubMed, Cochrane Library, LILACS, Scopus, Web of Science, Embase and grey literature. In the first step, two reviewers will independently evaluate the articles by titles and abstracts, then, a full review of the selected articles will be performed according to the inclusion and exclusion criteria. Any uncertainties or differences of opinion will be discussed for consensus. Articles published without date or language restrictions will be included. All components will be presented in tables and flow charts. In addition, a narrative summary of each component will be included for further details. Final Considerations: this protocol will present the general state of the literature on the use of wearables in masseter and temporal masticatory muscles.

RESUMO Objetivo: desenvolver um protocolo de revisão de escopo que busque identificar quais procedimentos e com que finalidade as tecnologias vestíveis disponíveis na literatura estão sendo usadas nos músculos masseter e temporal. Métodos: seguirá a abordagem recomendada pelo The Joanna Briggs Institute e as diretrizes PRISMA-P. As bases de dados a serem pesquisadas incluem PubMed, Cochrane Library, LILACS, Scopus, Web of Science, Embase e literatura cinzenta. Em uma primeira etapa, dois revisores, de forma independente, avaliarão os artigos pelos títulos e resumos, em seguida, será realizada a revisão na íntegra dos artigos selecionados de acordo com os critérios de inclusão e exclusão. Quaisquer incertezas ou diferenças de opinião serão discutidas para consenso. Serão incluídos artigos publicados sem restrição de data e idioma. Todos os componentes serão apresentados em tabelas e fluxogramas. Além disso, um resumo narrativo de cada componente será incluído para mais detalhes. Considerações finais: este protocolo irá apresentar o estado geral da literatura acerca do uso das tecnologias vestíveis na musculatura mastigatória de masseter e temporal.

Masticatory function according to body mass index: part II: electromyographic analysis / Función masticatoria según índice de masa corporal: parte II: análisis electromiográfico

Introduction: The objective of this study was to explore the electrical activity of the superficial muscles of mastication required to exert unilateral maximum bite force in subjects with different body mass index. Material and Methods: A cross-sectional observational study was conducted with a sample of 21 participants with an average age of 22.9 ± 3.5 years who were classified according to their body mass index, forming three study groups: normal weight (18.5-24.9), overweight (25-29.9) and obesity (≥30), with seven participants each. Through surface electromyography, the superficial muscles of mastication during right and left maximum bite force were evaluated. Results: No statistically significant differences in the maximum bite force were observed between the study groups. The data obtained from the electromyographic analysis of the superficial muscles of mastication demonstrate a trend indicating that subjects with a normal body mass index similarly activate the muscles on each side when performing a maximum bite force on a particular side, while overweight or obese subjects demonstrated significantly greater activation of the temporalis muscle associated with the side where the maximal bite force is performed. Conclusion: Our findings suggest that the maximum bite force is not influenced by body mass index and that during the performance of a maximum bite force subjects with increased body mass index present a greater activation of the temporalis muscle associated with the side where the maximum bite force was performed.

Introducción: El objetivo de este estudio fue explorar la actividad eléctrica de los músculos superficiales de la masticación, necesarios para ejercer la máxima fuerza de mordida unilateral, en sujetos con diferente índice de masa corporal. Material y Métodos: Se realizó un estudio observacional de corte transversal con una muestra de 21 participantes con una edad promedio de 22.9 ± 3.5 años, quienes fueron clasificados de acuerdo a su índice de masa corporal, formando tres grupos de estudio: peso normal (18,5-24,9), sobrepeso (25,0-29,9) y obesidad (≥30.0), con siete participantes cada uno. La electromiografía de superficie evaluó los músculos superficiales de la masticación durante la fuerza de mordida máxima derecha e izquierda. Resultados: No se observaron diferencias estadísticamente significativas en la fuerza de mordida máxima entre los grupos de estudio. Los datos obtenidos del análisis electromiográfico de los músculos superficiales de la masticación demuestran una tendencia que indica que los sujetos con un índice de masa corporal normal activan de manera similar los músculos de cada lado cuando ejercen la fuerza de mordida máxima en un lado en particular. mientras que los sujetos con sobrepeso u obesos demostraron una activación significativamente mayor del músculo temporal asociado con el lado donde se realiza la fuerza máxima de mordida. Conclusión: Nuestros hallazgos sugieren que la fuerza de mordida máxima no está influenciada por el índice de masa corporal y que durante la realización de una fuerza de mordida máxima los sujetos con índice de masa corporal aumentado presentan una mayor activación del músculo temporal asociado al lado donde se realizó la fuerza de mordida máxima.

Dores musculares cervicais em pacientes com DTM e suas correlações / Cervical muscle pain in patients with TMD and its correlations

Introdução: As disfunções temporomandibulares apresentam uma variedade de sinais e sintomas que afetam a articulação temporomandibular, músculos da mastigação e estruturas relacionadas e muitos pacientes apresentam queixas cervicais. Objetivo: Verificar a correlação de dor à palpação dos músculos da mastigação (masseter, temporal anterior, pterigoideos lateral e medial) e digástrico, com a queixa de dor no pescoço; verificar a correlação de dor à palpação nos músculos da mastigação e digástrico, com dor à palpação no esternocleidomastoideo e trapézio, e se a força de correlação é diferente entre eles. Material e método: Foram avaliados 232 prontuários da clínica odontológica das Disfunções Temporomandibulares da Faculdade de Odontologia de Araçatuba, do período de 2011 a 2013. Os dados coletados foram submetidos à análise estatística, com alfa (α) = 0.01 para todos os casos, exceto digástrico quando associado ao trapézio (α) = 0.05. Resultado: A maioria dos pacientes era do sexo feminino. Houve correlação positiva entre dor à palpação nos músculos temporal, masseter, pterigoideo lateral, esternocleidomastoideo e trapézio, e queixa de dor no pescoço. Também houve correlação positiva entre a dor em todos os músculos da mastigação (masseter, temporal, pterigoideo lateral e medial) e digástrico e a dor no esternocleidomastoideo. Bem como a correlação de presença de dor nos músculos masseter, temporal, pterigoideo lateral e digástrico com dor no trapézio. A correlação de dor foi mais forte para o músculo esternocleidomastoideo, exceto para o pterigoideo lateral. Conclusão: Existe correlação positiva entre a queixa de dor à palpação nos músculos da mastigação, exceto pterigiodeo medial, e os músculos cervicais (esternocleidomastoideo e trapézio). A força de correlação entre a dor do masseter e temporal anterior com o esternocleidomastoideo é mais forte do que com o trapézio.

Introduction: Temporomandibular disorders present a variety of signs and symptoms that affect the temporomandibular joint, masticatory muscles and related structures, and many patients have cervical complaints. Objective: To verify the correlation of pain on palpation of the mastication muscles (masseter, anterior temporal, lateral and medial pterygoid), and digastric muscles with the complaint of neck pain; to verify the correlation of pain on palpation in the masticatory and digastric muscles with pain on palpation in the sternocleidomastoid and trapezius and if the correlation strength is different between them. Material and method: From 2011 to 2013, 232 medical records from the dental clinic of Temporomandibular Disorders of the Faculty of Dentistry of Araçatuba were evaluated. The data collected were submitted to statistical analysis, with alpha (α) = 0.01 for all cases, except digastric when associated with the trapezoid (α) = 0.05. Result Most patients were female. There was a positive correlation between pain on palpation in the temporal, masseter, lateral pterygoid, sternocleidomastoid and trapezius muscles, and complaints of neck pain. There was also a positive correlation between pain in all muscles of mastication (masseter, temporal, lateral and medial pterygoid), and digastric and sternocleidomastoid pain. As well as the correlation of the presence of pain in the masseter, temporal, lateral pterygoid and digastric muscles with pain in the trapezius. Pain correlation was strongest for the sternocleidomastoid muscle, except for the lateral pterygoid. Conclusion There is a positive correlation between the complaint of pain on palpation in the masticatory muscles, except Medial pterygoid, with the cervical muscles (sternocleidomastoid and trapezius). The strength of correlation between masseter and anterior temporal pain with the sternocleidomastoid is stronger than with the trapezius.

O uso da bandagem elástica adesiva para alívio da dor no tratamento das disfunções temporomandibulares: revisão sistemática com metanálise / Use of kinesiology tape for pain relief in the treatment of temporomandibular disorders: a systematic review with meta-analysis

RESUMO Objetivos Verificar o efeito da aplicação da bandagem elástica sobre músculos mastigatórios no alívio da dor, em comparação com outras intervenções, em indivíduos com disfunções temporomandibulares. Estratégia de pesquisa Busca nas bases de dados LILACS, IBECS, CINAHL, Scopus, Web of Science, Cochrane, Embase e MEDLINE. A pergunta norteadora, utilizando-se os elementos da estratégia PICOT (população, intervenção, comparador, outcome/desfecho, tipo de estudo) foi: "A bandagem elástica promove alívio da dor em indivíduos com disfunção temporomandibular?". Critérios de seleção Foram incluídos ensaios clínicos que fizeram uso da bandagem elástica em músculos mastigatórios de indivíduos com disfunção temporomandibular, publicados em português, inglês ou espanhol. Foram excluídos os artigos que não abordavam o método de aplicação e o desfecho "intensidade da dor". A avaliação da elegibilidade foi realizada pela leitura dos títulos e resumos, bem como pela leitura dos estudos na íntegra. Foram extraídas informações sobre ano de publicação, país de condução do estudo, idade e condição clínica da amostra, tratamento e resultados da avaliação da dor. Na metanálise, realizada por meio do método do inverso da variância, a média do valor indicado na escala visual analógica foi considerada como medida de efeito da intervenção. Resultados Foram localizadas, inicialmente, 344 referências, das quais, 3 foram selecionadas. Foram identificados resultados significativamente superiores na redução da dor, em uma semana de uso da bandagem, na comparação com outras abordagens conservadoras analisadas. Conclusão Considerando os artigos incluídos, a bandagem elástica apresentou resultados significativos para maior redução da dor na primeira semana. Porém, o número reduzido de estudos e a presença de vieses limitam os achados.

ABSTRACT Purpose To verify the effects on pain relief by applying kinesiology tape on the masticatory muscles, in comparison with other interventions, in people with temporomandibular disorders. Research strategy Search in LILACS, IBECS, CINAHL, Scopus, Web of Science, Cochrane, EMBASE, and MEDLINE. The research question, based on the PICOT components, was: "Does kinesiology tape applied on to masticatory muscles relieve the pain in people with temporomandibular disorders?". Selection criteria The included articles were clinical trials using kinesiology tape on masticatory muscles in people with temporomandibular disorders, published in Portuguese, English, or Spanish. Articles whose authors had not adopted this application method and pain intensity as an outcome were excluded. Eligibility was assessed by reading their titles, abstracts, and full texts. The following information was extracted: year of publication, the country where the study was conducted, age and clinical condition of the sample, treatment, and pain assessment results. The meta-analysis, using the inverse variance method, considered the mean value indicated in the visual analog scale as the intervention effect measure. Results Initially, 344 references were retrieved, of which three were selected. Significantly better pain relief results were identified after 1 week of using the tape, in comparison with the other conservative approaches analyzed. Conclusion Considering the included articles, the kinesiology tape had significant results with greater pain relief in the first week. However, small number of studies and their biases limit the findings.

Análise de diferentes tarefas para normalização do sinal elétrico do músculo orbicular da boca pela contração voluntária máxima: estudo piloto / Analysis of different tasks to normalize the electrical signal of the orbicularis oris muscle by maximum voluntary contraction: pilot study

RESUMO Objetivo pesquisar a atividade elétrica do músculo orbicular da boca em quatro diferentes tarefas isométricas e indicar a mais apropriada para utilização como referência na normalização do sinal elétrico do músculo orbicular da boca pela contração voluntária máxima. Métodos participaram do estudo 22 indivíduos, sendo dez do sexo masculino e 12 do feminino, com idades entre 20 e 33 anos. A atividade elétrica das porções superior e inferior do músculo orbicular da boca foi registrada durante a realização das seguintes tarefas isométricas: protrusão labial com fechamento, protrusão labial sem fechamento, contrarresistência com a placa de resistência labial e preensão de lábios. A ordem de realização das tarefas foi randomizada entre os participantes. Os dados foram comparados entre as tarefas, para cada seguimento labial. Resultados no segmento marginal superior, a tarefa com maior média e mediana de amplitude foi preensão labial, embora sem diferença significativa entre tarefas. O menor coeficiente de variação foi obtido na tarefa de contrarresistência com a placa de resistência labial. No segmento marginal inferior, a tarefa com maior média e mediana de amplitude foi protrusão labial com fechamento, que também teve o menor coeficiente de variação e diferença significativa entre as tarefas protrusão labial com fechamento e preensão, sendo os maiores valores obtidos na primeira. Conclusão indica-se como referência para a normalização do sinal elétrico do músculo orbicular da boca, pela contração voluntária máxima, a tarefa de protrusão labial com fechamento.

ABSTRACT Purpose To verify the electrical activity of the orbicularis oris in four different isometric tasks and to indicate the most appropriate task for use as a reference in the normalization of the electrical signal of the orbicularis oris muscle by maximum voluntary contraction. Methods Twenty-two individuals participated in the study, of which 10 were male and 12 were female, with ages ranging from 20 to 33 years. The electrical activity of the upper and lower parts of orbicularis oris muscle was recorded during the following isometric tasks: lip protrusion with bilabial closure; lip protrusion without bilabial closure; the counter resistance using the plate of labial resistance and lips prehension. The order of the tasks was randomized among participants. Data were compared between tasks for each lip part. Results in the upper marginal segment, the task with the highest mean and median amplitude was lip prehension, although there was no significant difference between tasks. The lowest coefficient of variation was obtained in the counter resistance task with the plate of labial resistance. In the lower marginal segment, the task with the highest mean and median amplitude was labial protrusion with lips closure, which also had the lowest coefficient of variation. In this segment, there was a significant difference between labial protrusion with lips closure and prehension, with the highest values obtained in the first task. Conclusion lip protrusion with bilabial closure is suggested as reference for the normalization of the electrical signal of the orbicularis oris muscle, by maximum voluntary contraction.

Factors associated with bite force in people with Parkinson's disease / Fatores associados à força de mordida em pessoas com doença de Parkinson

ABSTRACT Purpose: to assess the bite force in people with Parkinson's disease and correlate it with age, sex, stage and time of the disease, dentures use, presence of temporomandibular disorder, side of symptom onset, and masticatory preference. Methods: the Research Diagnostic Criteria for Temporomandibular Disorders and the Hoehn & Yahr Parkinson's disease scale were used, and the participants' oral cavity was clinically examined. Then, the bite force was measured with an analog dynamometer, whose bar was adapted for mouth grip. The bite force results and their correlation with the variables were analyzed with the independent t-test (p<0.05). Results: the sample comprised 42 parkinsonians at a mean age of 64 years, 67% of whom were males. No difference was observed in the correlation with age, temporomandibular disorder, stage and time of Parkinson's disease; or between the sides, symptom onset and masticatory preference. However, there was a significant association between the sexes (males and females) for both sides (right - p=0.002; left - p=0.04) and denture use for bite force on the right side (p=0.03). Conclusion: being a female and using dentures are factors associated with decreased bite force in people with Parkinson's disease.

RESUMO Objetivo: avaliar a força de mordida em pessoas com doença de Parkinson e correlacionar com: idade, sexo, estágio e tempo da doença, uso de prótese dentária, presença de disfunção temporomandibular, lado de início dos sintomas e preferência mastigatória. Métodos: foi aplicado o questionário Critério de Diagnóstico para Pesquisa em Disfunção Temporomandibular, a escala Hoehn & Yahr para estágio da doença de Parkinson e realizou-se o exame clínico da cavidade oral. Seguido do registro da força de mordida, utilizando um dinamômetro analógico, com haste adaptada para a preensão bucal. Os resultados obtidos da força de mordida e correlação com as variáveis foram analisadas por meio do teste T independente (p<0,05). Resultados: a amostra foi composta por 42 parkinsonianos com média de idade de 64 anos, desses 67% eram do sexo masculino. Observou-se não haver diferença na correlação com: idade, disfunção temporomandibular, estágio e tempo de diagnóstico da doença de Parkinson, bem como entre os lados, início dos sintomas e preferência mastigatória, no entanto, houve associação significante entre os sexos: masculino e feminino para ambos os lados (direito - p=0,002; esquerdo - p=0,04) e na utilização de prótese dentária para a força de mordida do lado direito (p=0,03). Conclusão: constatou-se que ser do sexo feminino e fazer uso de prótese dentária são fatores associados à redução da força de mordida em pessoas com doença de Parkinson.

Plasticidad muscular y fibras híbridas en la musculatura masticatoria: revisión de literatura / Muscle plasticity and hybrid fibers in the masticatory musculature: literature review

La musculatura masticatoria se caracteriza por presentar fibras híbridas que en los últimos años se han relacionado con el fenómeno de plasticidad muscular. El objetivo del estudio fue describir la relación entre la plasticidad muscular y las fibras musculares híbridas presentes en la musculatura masticatoria, mediante una revisión narrativa de literatura. Para esto, se realizó una búsqueda electrónica en PUBMED, ScienceDirect y BIREME, utilizando las palabras claves: "Muscle Plasticity", "Hybrid Muscle Fibers" y "Hybrid Fibers". Fueron seleccionados documentos que reportan las isoformas de cadena pesada de miosina (MHC) presentes en los músculos masticatorios de humanos y otros mamíferos, junto a los cambios vinculados a demandas funcionales. Se describe la presencia de fibras puras tipo I y tipo II, además de otras isoformas como la MHC-la, MHC-IIM, MHC-fetal y MHC-cardíaca. Sin embargo, un porcentaje considerable de fibras en la musculatura masticatoria son híbridas, es decir, expresan a más de una isoforma de MHC, las cuales también son diferentes a nivel intermuscular e intramuscular. Las influencias locales pueden contribuir a la variación de la expresión del tipo de fibra. En la musculatura masticatoria, el destete, la dureza de los alimentos, el bruxismo, la morfología craneofacial y el uso de prótesis dentales genera cambios a nivel de los músculos masticatorios, donde es común la presencia de fibras híbridas. Se concluye la presencia importante de fibras híbridas en la musculatura masticatoria y su relación con la plasticidad muscular a lo largo del ciclo vital, debido a cambios funcionales y patológicos. Es importante que los terapeutas de habla y motricidad orofacial profundicen en el conocimiento de la fisiología del comportamiento oromiofuncional.

The masticatory musculature is characterized by presenting hybrid fibers that in recent years have been related to the phenomenon of muscle plasticity. The objective of the study was to describe the relationship between muscle plasticity and the hybrid muscle fibers present in the masticatory muscles, through a narrative review. For this, an electronic search was conducted in PUBMED, ScienceDirect and BIREME, using the keywords: "Muscle Plasticity", "Hybrid Muscle Fibers" and "Hybrid Fibers". Documents that report the myosin heavy chain (MHC) isoforms present in the masticatory muscles of humans and other mammals were selected, along with the changes linked to functional demands. The presence of type I and type II pure fibers were described, in addition to other isoforms such as MHC-la, MHC-IIM, MHC-fetal and MHC-cardiac. However, a significant percentage of fibers in the masticatory muscles are hybrids, that is, they express more than one MHC isoform, which are also different at the intermuscular and intramuscular level. Local influences can contribute to the variation of fiber type expression. In the chewing muscles, weaning, the hardness of food, bruxism, craniofacial morphology and the use of dental prostheses generate changes at the level of the chewing muscles, where the presence of hybrid fibers is common. The important presence of hybrid fibers in the masticatory muscles and their relationship with muscle plasticity throughout the life cycle, due to functional and pathological changes, is concluded. It is important for Speech Therapy andMyofunctional Therapy to deepen their understanding of the physiology of oromyofunctional behavior.

Efecto del entrenamiento muscular masticatorio en el desarrollo del patrón vertical facial en niños: revisión narrativa / Training effect of the masticatory muscles in the development of the vertical facial pattern in children: narrative review

RESUMEN: Introducción: El patrón de crecimiento facial se establece antes de la aparición del primer molar permanente. Un exceso de crecimiento vertical facial, corresponde a individuos de cara larga, con ángulos goniacos abiertos, alturas faciales inferiores aumentadas y músculos masticatorios de menor área transversal. Esto se asocia a presentar mordida abierta anterior, mordida cruzada, clase II esquelético, entre otros. El entrenamiento muscular masticatorio podría controlar el excesivo crecimiento vertical, generando fuerzas opuestas que favorezcan un crecimiento horizontal. Objetivo: Describir el efecto del entrenamiento muscular masticatorio en el desarrollo del patrón vertical facial en niños. Método: Se realizó una revisión narrativa mediante búsqueda electrónica en las bases de datos PubMed, EBSCO, Scopus, Cochrane, Trip Database y Epistemonikos. Se utilizaron las palabras clave: "músculos masticatorios", "maseteros", "temporales", "masticación", "ejercicio", "entrenamiento", "crecimiento vertical", "patrón vertical", "dolicofacial", "control vertical". Los términos MeSH: "músculos masticatorios", "ejercicio". Resultados: Se seleccionaron 15 artículos de los cuales 9 son ensayos clínicos, 4 son reportes de caso y 2 son estudios observacionales transversales. Conclusiones: El entrenamiento muscular masticatorio tiene efectos positivos, favoreciendo un mayor crecimiento horizontal en niños con patrón vertical. No obstante, faltan estudios y ensayos clínicos para establecer y cuantificar los cambios morfológicos generados por el entrenamiento muscular.

ABSTRACT: Background: The pattern of facial growth is established before the eruption of the first permanent molar. An excess of vertical facial growth corresponds to individuals with long faces, open gonial angles, higher inferior facial heights and smaller masticatory muscles associated with different dental anomalies like anterior open bite, Brodie bite, skeletal class II and others. The masticatory muscle training could control the excessive growth in the vertical dimension, making opposing forces that will favor the horizontal growth in the patient. Objective: Describe the effect of the masticatory muscle training in the development of the vertical pattern in children. Method: A narrative review was done by an electronic research in PubMed, EBSCO, Scopus, Cochrane, Trip Database y Epistemonikos. The following key words were used: "masticatory muscles", "masseter", "temporalis", "mastication", "chewing", "exercise", "training", "vertical growth", "vertical pattern", "dolichofacial", "vertical control". The MeSH terms: "masticatory muscles", "exercise". Results: Fifteen articles were selected, 9 of them were clinical trials, 4 were case reports and 2 were observational studies. Conclusions: The literature review shows that the masticatory muscle training has positive effects, favoring the horizontal growth in children with vertical facial pattern. Nevertheless, there is a lack of studies and clinical trials, that could help us to establish and quantify the morphological changes made by the masticatory muscle training.

Correlations between masticatory muscle activity, quality of life, and dysfunction severity in women with chronic temporomandibular disorder / Relação entre atividade elétrica mastigatória, qualidade de vida e gravidade da disfunção em mulheres com disfunção temporomandibular crônica

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.

El músculo esfenomandibular ¿es un músculo independiente o es un fascículo del músculo temporomandibular? / Sphenomandibular muscle, is an independent muscle or is a fascicle of temporomandibular muscle?

Desde los años 90, odontólogos británicos describieron la presencia del músculo esfenomandibular como un músculo masticador, luego fue estudiado por odontólogos brasileros y bolivianos, aún existe la errónea idea que su presencia no es real y se ha cuestionado que sea un músculo independiente. Objetivo: Demostrar la presencia del músculo esfenomandibular como músculo independiente y su relación con el músculo temporal. Material y métodos: Se siguió un proceso de disección especial sugerido por Campohermoso et al, para verificar al músculo esfenomandibular; se trabajó con siete hemicabezas humanas, Resultados: Todos los especímenes estudiados presentaron el músculo esfenomandibular, comprobando una inserción superior en la parte anterior de la apófisis pterigoides del hueso esfenoide retromaxilar muy cercana a la hendidura esfenoidea próxima al ingreso del nervio motor ocular común, y una inserción inferior en la cresta de la cara interna de la apófisis coronoides de la mandíbula; hay independencia de éste músculo con el músculo témporal. La media del promedio del músculo fue de 44,7 mm de largo, por 6,81 mm de ancho. Conclusiones: No es concluyente la presencia del músculo esfenomandibular, se requiere ampliar estudios en otras áreas como son aspectos embriológicos, fisiológicos, estructurales y clínicos, este estudio servirá como inicio de una línea de investigación analítica de los músculos masticadores.

Since the early 1990s, British dentists described the presence of the sphenomandibular muscle as a chewing muscle, then it was studied by Brazilian and Bolivian dentists, still exists the erroneous idea that his presence is real and has been questioned as an independent muscle. Objective: To demonstrate the presence of muscle sphenomandibular as independent muscle and its relationship with the temporal muscle. Material and methods: Followed a special dissection process suggested by Campohermoso et al, to verify the sphenomandibular muscle; they worked with seven human hemicabezas. Results: all specimens studied showed muscle sphenomandibular, checking an insertion in the front part of the bone pterygoid process sphenoid retromaxillary very close to the cleft sphenoidal close to the entrance of the common ocular motor nerve, and an insert lower on the crest of the inner side of the jaw coronoid process; independence of this there is muscle with the temporal muscle. The mean average of the muscle was 44.7 mm long, by 6.81 mm wide. Conclusions: The presence of the sphenomandibular muscle is not conclusive, is required to further studies in other areas such as embryological, structural, physiological and clinical aspects, this study will serve as the beginning of a line of analytical research of the chewing muscles.

Relationships Between Tooth Loss and Masticatory Performance, Nutrition Intake, and Nutritional Status in the Elderly

Abstract Objective: To analyze the associations between posterior tooth loss and masticatory performance, nutrition intake, and nutritional status in the elderly. Material and Methods: A total of 158 subjects aged 60 years and older from Depok, West Java, Indonesia were enrolled in this cross-sectional study. Posterior teeth contacts were assessed and the subjects were divided into two groups based on Eichner Index; group A2-B3 and group B4-C3. The masticatory performance test was conducted using color-changeable chewing gum. A semi-quantitative food-frequency questionnaire was used to measure nutritional intake in the form of total calories, and the Mini-Nutritional Assessment-Short Form was used to measure nutritional status. Mann Whitney U test was used to determine differences in masticatory performance, nutrition intake, and nutritional status between the two groups Results: Seventy-four percent of participants were female, and 26% were male. A significant difference in the mean masticatory performance score (p<0.001) was noted between Eichner group A2-B3 (5.66 ± 1.80) and B4-C3 (3.20 ± 1.25). However, no statistically significant difference in nutritional status and calorie intake were found between the two groups (p>0.05) Conclusion: Despite the adequacy of nutrition intake and nutrition status in this population, tooth replacement is necessary to improve masticatory performance in both groups.

Tratamento de disfunções temporomandibulares com toxina botulínica tipo A / Treatment of temporomandibular disorders with botulinum toxin type A

Introdução: a disfunção temporomandibular (DTM) abrange muitos problemas clínicos nas articulações, na musculatura e em outras regiões da oroface. A origem multifatorial e sua etiologia envolvem fatores psicocomportamentais, oclusais e neuromusculares, seu diagnóstico é realizado pela anamnese detalhada, com a identificação dos fatores predisponentes, iniciadores e perpetuantes, e pelo exame físico, que consiste em palpação da musculatura, mensuração da movimentação ativa e verificação dos ruídos articulares. Objetivo: sistematizar as evidências científicas e verificar a eficácia do tratamento de disfunções temporomandibulares de origem muscular com a toxina botulínica do tipo A (TBX-A). Materiais e método: a busca bibliográfica foi realizada nas bases de dados PubMed e SciELO, com os descritores: "myofascial pain", "botulinum toxin" e "masticatory muscles". Foram analisados ensaios clínicos randomizados, que apresentaram tratamento para DTM com a utilização da TBX-A em pacientes de ambos os sexos. A qualidade metodológica dos artigos selecionados foi verificada de acordo com a escala de Jadad. Considerações finais: observou-se que o tratamento para a DTM por meio da TBX-A auxilia no tratamento de dores orofaciais permanentes como coadjuvante, aliado a tratamentos conservadores. Os estudos que demonstraram resultados clínicos significativos utilizaram uma dose total de 100 U de TBX-A, sendo 30 U nos músculos masseteres e 20 U nos músculos temporais, bilateralmente. (AU)

Introduction: temporomandibular dysfunction (TMD) involves a number of clinical problems in joints, muscles, and other orofacial regions. The multifactorial origin and etiology involve psychobehavioral, occlusal, and neuromuscular factors. The diagnosis is performed by a detailed anamnesis with the identification of predisposing factors, initiators and perpetuants, and the physical examination, which consists of muscle palpation, measurement of the active movement, and verification of joint noises. Objective: to systematize the scientific evidence and to verify the efficacy of treatment of temporomandibular disorders of muscular origin with botulinum toxin type A (TBX-A). Materials and method: the bibliographic search was performed in the PubMed and SciELO databases, with the descriptors of "myofascial pain", "botulinum toxin", "masticatory muscles". Randomized clinical trials that presented treatment for TMD with the use of TBX-A in patients of both sexes were analyzed. The methodological quality of the articles selected was verified according to the Jadad scale. Final considerations: it was observed that treatment for TMD using TBX-A helps to treat permanent orofacial pain as a support, along with conservative treatments. The studies showing significant clinical outcomes used a total dose of 100 U of TBX-A, considering 30 U for the masseter muscles and 20 U for the temporal muscles, bilaterally. (AU)

Effect of breast cancer treatment on the stomatognathic system

Abstract Breast cancer is the most common cancer affecting women in the world and provides functional changes in the human body. Evaluate women submitted to unilateral mastectomy, through electromyographic activity (mandibular rest, right and left laterality, protrusion, maximum voluntary contraction with and without Parafilm, habitual and non-habitual mastication) and thickness (rest and maximum voluntary contraction) of the right temporal muscle (RT), left temporal (LT), right masseter (RM) and left masseter (LM), also the molar bite force (right and left) and compare the data with healthy women. Material and Methods: 32 women were divided into two groups: unilateral mastectomy group (MG), average ± standard deviation 56.50±14.50 years (n=16) and without the disease group (CG), average ± standard deviation 56.56±14.15 years (n=16). The normalized electromyographic data, muscle thickness and maximal molar bite force were tabulated and submitted to statistical analysis (SPSS 21.0; student t test, p≤0.05). Significant statistical differences between MG and CG were found in right laterality, for RM (p=0.02); left laterality, for LT (p=0.01); chewing with peanuts, for RM (p=0.04); chewing with raisins, for LM (p=0.04) and right molar bite force (p=0.03). There was no statistically significant difference between MG and CG for muscle thickness. The results of this study suggest that women undergoing unilateral mastectomy may present functional changes, with emphasis on muscular hyperactivity, lower masticatory efficiency and lower maxillary bite force.

Resumo Câncer de mama é a neoplasia mais comum que mais acomete mulheres no mundo e proporciona alterações funcionais no corpo humano. Objetivo: avaliar mulheres submetidas à mastectomia unilateral, por meio da atividade eletromiográfica (repouso mandibular, lateralidade direita e esquerda, protrusão, contração voluntária máxima com e sem parafilme, mastigação habitual e não habitual) e espessura (repouso e contração voluntária máxima) do músculo temporal direito (TD), temporal esquerdo (TE), masseter direito (MD) e masseter esquerdo (ME), além da força de mordida molar (direita e esquerda) e comparar os dados com mulheres saudáveis. 32 mulheres foram distribuídas em dois grupos: grupo mastectomia unilateral (GM), média ± desvio padrão 56,50 ± 14,50 anos (n=16) e grupo sem a doença (GC), média ± desvio padrão 56,56 ± 14,15 anos (n=16). Os dados eletromiográficos normalizados, espessura muscular e força de mordida molar máxima foram tabulados e submetidos à análise estatística (SPSS 21.0; teste t de student, p≤0,05). Foram encontradas diferenças estatísticas significantes entre GM e GC na lateralidade direita, para o MD (p=0,02); lateralidade esquerda, para o TE (p=0,01); mastigação com amendoim, para o MD (p=0,04); mastigação com uva-passa, para o ME (p=0,04) e força de mordida molar direita (p=0,03). Não houve diferença estatística significante entre GM e GC para espessura muscular. Os resultados deste estudo sugerem que mulheres submetidas à mastectomia unilateral podem apresentar alterações funcionais do sistema estomatognático, com destaque para hiperatividade muscular, menor eficiência mastigatória e menor força de mordida molar máxima.

Alterations in the stomatognathic system due to amyotrophic lateral sclerosis

Abstract Objectives: To compare the molar bite force, electromyographic activity, chewing efficiency and thickness of the masseter and temporalis muscles in individuals with amyotrophic lateral sclerosis (ALS) and healthy individuals. Material and Methods: Thirty individuals enrolled in the study were divided into the study group (with ALS, n=15) and control group (healthy individuals, n=15). Data regarding molar bite force (right and left), electromyographic activity (mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction), chewing efficiency (habitual and non-habitual), and masticatory muscle thickness (rest and maximum voluntary contraction) were tabulated and subjected to statistical analysis (Student's t-test, p≤0.05). Results: Comparisons between the groups demonstrated a statistically significant increase in the electromyographic activity of the right masseter (p=0.03) and left masseter (p=0.03) muscles during mandibular rest; left masseter (p=0.00), right temporalis (p=0.00), and left temporalis (p=0.03) muscles during protrusion; and right masseter (p=0.00), left masseter (p=0.00), and left temporalis (p=0.00) muscles during left laterality, in individuals with ALS as compared with healthy individuals. A statistically significant decrease was observed in the habitual chewing efficiency of the right masseter (p=0.00) and right temporalis (p=0.04) muscles in individuals with ALS. No statistically significant difference between the groups was found the masticatory muscle thickness and maximal molar bite force. Conclusions: ALS may lead to modifications in the activities of the stomatognathic system, including muscular hyperactivity and reduction in chewing efficiency; however, no change has been observed in the masticatory muscle thickness and molar bite force.

Immediate effects of temporary bite-raising with light-cured orthodontic band cement on the electromyographic response of masticatory muscles

Abstract Objective: To assess the immediate effects of temporary bite-raising using light-cured orthodontic band cement on the superficial masseter and anterior temporalis electromyography (EMG) activity in healthy adults. Materials and Methods: Surface EMG signals were recorded bilaterally from the superficial masseter and anterior temporalis muscles of 30 volunteers with a normal occlusion, before and after having temporary bite-raising. The bite-raising was done by adding light-cured orthodontic band cement (3x5x2 mm WxLxH) on the lingual cusps of both upper first molars. The measurements were recorded (i) at rest, (ii) while clenching in centric occluding position and (iii) while chewing on an artificial test food. The EMG activity at rest and during clenching, the maximum voltage, and the duration of the identified EMG signal burst while chewing the artificial test food before and after temporary bite-raising were statistically compared using the paired t-test or the Wilcoxon signed-rank test based on the normality of the variables. The significance level was set at 5%. Results: After temporary bite-raising, we found no significant change in integral EMG activity at rest position for the superficial masseter (mean difference (MD)=7.5 μVs) and for the anterior temporalis muscle (MD=36.8 μVs); however, the integral EMG activity during clenching was significantly reduced for the superficial masseter (MD=201.2 μVs) and for the anterior temporalis muscle (MD=151.8 μVs). During mastication, the maximum voltage of the identified burst was significantly reduced on the preferred chewing side of the superficial masseter and anterior temporalis muscles (MD=127.9 and 47.7 μV, respectively), while no significant change was found for the duration of the identified burst (MD=-34.1 and 3.4 ms, respectively) after temporary bite-raising. Conclusion: The results point to an altered neuromuscular behavior during clenching and chewing immediately after temporary bite-raising with light-cured orthodontic band cement. This information is relevant for orthodontists to inform their patients what will happen to their masticatory muscle activity when this bite-raising method is used.