Electromyographic analysis of the stomatognathic system of children with Molar-incisor hypomineralization.

INTRODUCTION: Molar-incisor hypomineralization (MIH) is a qualitative defect of dental enamel that affects one or more permanent first molars, with or without involvement of the incisor teeth. This condition leads to challenges to dental care and treatment planning. AIM: Based on the hypothesis that children who have MIH possibly present alterations in postural and masticatory activities and considering the absence of studies investigating these parameters, the present study evaluated the functionality of the stomatognathic system considering the mentioned aspects. MATERIALS: The comparison of individuals with (MIHG; n = 32) and without MIH (CG; n = 32) was evaluated by electromyographic activity of the masseter and temporal muscles (right and left), as well as evaluation of the masticatory cycles during habitual mastication. RESULTS: MIHG showed muscle hyperactivity in postural and dynamic conditions compared to the CG; higher electromyographic values for MIHG when compared to CG in the following postural conditions: at rest for the right temporal (p = 0.00) and left temporal muscles (p = 0.03); in the protrusion to the right temporal muscle (p = 0.02); in the right laterality for the right masseter (p = 0.00) and left temporal muscles (p = 0.01); in the left laterality for the right masseter (p = 0.03) and left temporal (p = 0.04) muscles. In dynamic conditions with consistent food, significance was observed for the left temporal (p = 0.01); and with soft food for the right (p = 0.01) and left temporal muscles (p = 0.04). CONCLUSIONS: Children with MIH seem to have impaired functionality of the stomatognathic system. Children with MIH have alterations in the stomatognathic system.

Effect of Breast Cancer Treatment on the Stomatognathic System.

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.

Alterations in the stomatognathic system due to amyotrophic lateral sclerosis.

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.

Effect of implant crestal position on primary stability before and after loading: an in vitro study / Efeito do posicionamento crestal do implante na estabilidade primária antes e após carga: um estudo in vitro

Introduction: Primary stability is one of the goals of modern implant dentistry and if achieved, reduces treatment time for prosthetic rehabilitation and the number of interventions made in patients mouth. Several companies state as protocol for connical conection implants, a subcrestally positioning. Objective: This in vitro study aimed to evaluate the effect of placing a conical connection implant equicrestally and subcrestally on static and loading condition in two types of bone density. Material and method: A total of 200 bone cylinders were extracted from femur of pigs, standardized by means of x-rays and computerized microtomography scan (microCT) and separated in low and high density specimens. The implants were placed on the center of the bone cylinders and were evaluated before and after loading by means of microCT and histomorphometry. Result: The results showed that placing the evaluated implant subcrestally provided better primary stability and performance on static and loading situations on low and high density bone. Conclusion: Placing implant subcrestally improve primary stability outcomes under loading and static situations.

Introdução: A estabilidade primária é um dos objetivos da implantodontia moderna e, caso atingida, reduz o tempo de tratamento para a reabilitação protéticas e o número de intervenções realizadas. Diversas empresas preconizam a posição subcrestal no uso de implantes com conexão cônica interna. Objetivo: Este estudo in vitro avaliou o efeito do posicionamento de implantes de conexão conica interna sub e equicrestal sob condições estáticas e em função, considerando dois tipos de densidades ósseas. Material e método: um total de 200 espécimes de osso extraído do femur de suínos e padronizados por meio de radiografias e microtomografias computadorizadas foram separados em densidade alta e baixa. Implantes foram instalados no centro dos especimes e for a avaliados por meio de microCT e histomorfometria. Resultado: Os resultados demonstraram que a colocação de implante subcrestalmente promoveu melhor estabilidade primária e performance em todas as situações, irrespectivamente à densidade óssea. Conclusão: A colocação de implantes subcrestalmente melhora a estabilidade primária em todas as situações, sendo indicada quando da utilização de conexões cônicas internas.

Lucia Jig - temporomandibular dysfunction promotes muscle relaxation? / Jig de Lucia - disfunção temporomandibular promove relaxamento muscular?

Assess whether the Lucia Jig is a device that promotes masticatory muscle relaxation in individuals with temporomandibular dysfunction. This study was carried out in three stages (interviews, clinical examination, and laboratory) and participation of adult individuals, between 21 and 40 years of age, of both genders, who replied to the RDC/TMD questionnaire to diagnose muscular temporomandibular dysfunction. The Lucia Jig was prepared and electromyographic examination of the masseter and temporal muscles was performed bilaterally, in the postural condition of the mandibular at rest, after immediately installing the Lucia Jig in the oral cavity and at periods of 5, 10, 15, 20, and 30 min. The values obtained were compared using repeated measures (p < 0.05) over the entire duration of the experiment (0 to 30 min) with the Lucia Jig. There was an increase in the normalized electromyographic signal of the masticatory muscles, with the use of the Lucia Jig over the period of 30 min, with no statistically significant difference. Based on the results of this study through electromyographic data, the device did not promote masticatory muscle relaxation in individuals with muscular temporomandibular dysfunction.

Avaliar se o Jig de Lucia é um dispositivo que promove relaxamento dos músculos mastigatórios em indivíduos com disfunção temporomandibular. O estudo foi realizado em três etapas (entrevista, exame clínico e laboratorial) com a participação de indivíduos adultos, entre 21 e 40 anos de idade, ambos os gêneros, que responderam ao questionário RDC/TMD para diagnosticar disfunção temporomandibular muscular. O Jig de Lucia foi confeccionado e o exame eletromiográfico foi realizado nos músculos masseter e temporal, bilateralmente, na condição postural da mandíbula em repouso e imediatamente depois da instalação do Jig de Lucia na cavidade oral nos períodos de 5, 10, 15, 20 e 30 min. Os valores obtidos foram comparados ao longo de toda a duração do experimento (0 a 30 min) com o Jig de Lucia, utilizando o teste de medidas repetidas (p <0,05). Houve aumento no sinal EMG normalizado dos músculos da mastigação, com o uso do Jig de Lucia ao longo do período de 30 min, sem diferença estatística significante. Com base nos resultados deste estudo, conclui-se que o dispositivo Jig de Lucia, por meio dos dados eletromiográficos, não promove relaxamento dos músculos mastigatórios em indivíduos com disfunção temporomandibular muscular.

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.

Efeito da placa oclusal resiliente nos músculos masseter e temporal em pacientes com disfunção temporomandibular / Effect of soft occlusal splint in masseter and temporal muscles patientswith temporomandibular dysfunction

Introdução: A disfunção temporomandibular é uma alteração patológica que afeta os músculos da mastigação, a articulação temporomandibular ou ambos, e vem se tornando cada vez mais frequente na Odontologia. Objetivo: O objetivo deste estudo foi analisar o efeito do tratamento com placa oclusal resiliente na atividade eletromiográfica dos músculos masseter e temporal, e na força de mordida molar máxima em pacientes portadores de disfunção temporomandibular. Material e método: Foram selecionados 12 pacientes do Serviço de Dor Orofacial e Disfunção Temporomandibular do Centro de Pacientes Especiais da FORP USP com disfunção temporomandibular, diagnosticados pelo índice RDC TMD, e submetidos a exames eletromiográficos e de força de mordida molar máxima antes, 45 e 90 dias após o uso noturno da placa oclusal resiliente. Resultado: As médias eletromiográficas normalizadas obtidas dos músculos masseter e temporal durante as condições clínicas de repouso, protrusão, lateralidade direita e esquerda, apertamento dental em contração voluntária máxima e a força de mordida molar máxima direita e esquerda foram analisadas estatisticamente utilizando o software aspas Statistical Package for the Social Sciences aspas SPSS versão 17,0 (Chicago, IL), tendo sido executado o teste-t pareado. Os dados foram submetidos à análise estatística com um nível de confiança de 95% (p < 0,05). Conclusão: Os autores observaram que, após o uso da placa oclusal resiliente nas condições clínicas propostas, ocorreram alterações satisfatórias nos valores eletromiográficos e houve um aumento da força de mordida.

Introduction: Temporomandibular dysfunction is a pathological change that affects the muscles of mastication, the temporomandibular joint or both and is becoming more and more frequent in dentistry. Objective: The aim of this study was to analyze the effect of treatment with soft occlusal splint on the electromyographic activity of masseter and temporal muscles and maximal molar bite force in patients with temporomandibular disorders. Material and Method: Were selected twelve patients in the Department of Orofacial Pain and Temporomandibular Disorders Center Patient Special FORP USP with temporomandibular disorder, diagnosed by the RDC TMD index, and underwent an examination of EMG and maximal molar bite force before forty and five to ninety days after the nightly use of soft occlusal splints. Result: The mean normalized EMG obtained from the masseter and temporal muscles obtained during the clinical conditions of rest, protrusion, right and left laterality, clenching in maximum voluntary contraction force and maximal molar bite right and left were statistically analyzed using the software aspas Statistical Package for the Social Sciences aspas SPSS version 17,0 (Chicago, IL), where he was executed the paired t-test, Data were subjected to statistical analysis (SPSS 17,0) with a confidence level of 95% (p < 0.05). Conclusion: The authors observed that after using the occlusal soft occlusal splint in clinical conditions satisfactory changes occurred quotes, on the values electromyographic and there was an increase in the strength of bite.

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.

Este estudo teve como objetivo analisar a atividade eletromiográfica e a força de mordida molar máxima de indivíduos diagnosticados com osteoporose na região maxilar e mandibular, visto que os hábitos e condições que provocam o desenvolvimento de uma perda óssea generalizada no esqueleto, inclusive no esqueleto facial, podem causar distúrbios na harmonia funcional do sistema mastigatório. Vinte e sete indivíduos portadores de osteoporose na mandíbula e maxila e 27 voluntários sem a doença participaram deste estudo. Um eletromiógrafo de 5 canais foi utilizado. A avaliação da atividade muscular foi realizada por meio de registros eletromiográficos da musculatura mastigatória (músculos masseter e temporal, bilateralmente) durante as seguintes condições clínicas: Repouso (5 s); Lateralidades direita e esquerda (5 s); Protrusão (5 s); Apertamento dental máximo com parafilme (4 s) e a contração voluntária máxima (4 s), sendo que esta condição clínica foi utilizada como fator de normalização dos dados da amostra. Verificou-se que os indivíduos com osteoporose apresentaram maior atividade eletromiográfica durante a manutenção das condições posturais da mandíbula e menor atividade durante o apertamento dental e na obtenção da força de mordida molar máxima. Conclui-se que a osteoporose na região dos ossos da face pode interferir nos padrões de ativação da musculatura mastigatória e na força de mordida máxima do sistema estomatognático.