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Rheumatoid arthritis and osteoarthritis both affect the articular cartilage, and are characterized by signs and symptoms that can affect the functions of the human body. This cross-sectional observational study evaluated electromyographic activity in the masseter and temporalis muscles, molar bite force, and mandibular mobility in adult women with rheumatoid arthritis or osteoarthritis. A total of 42 women were distributed into 3 groups: rheumatoid arthritis group (ARG, n=14); osteoarthritis group (OAG, n=14); and a healthy control group (CG, n=14). Electromyography was used to evaluate mandibular tasks at rest, right and left laterality, protrusion, and dental clenching during maximum voluntary contraction, with and without parafilm, and a dynamometer was used to analyse the right and left molar bite forces. A digital caliper was used to measure the range of mandibular movement for maximum mouth opening, right and left laterality, and protrusion. Statistical analyses were performed, including analysis of variance and Tukey's test (P<0.05). Electromyography showed no significant differences between the groups when evaluating the masticatory muscles during the mandibular tasks. Significant difference was observed between the ARG and CG, however, in the maximum right (P=0.007) and left (P=0.02) molar bite forces. Significant difference was observed in the maximum mouth opening of the ARG and OAG groups compared with that of the CG (P=0.009), suggesting that adult women with rheumatoid arthritis or osteoarthritis experience functional alterations in the stomatognathic system, particularly in molar bite force and maximum mouth opening.

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The presence of myofascial trigger points in the masticatory muscles can lead to pain and may be related to temporomandibular dysfunction. The dry needling technique (DN) is employed for mechanical disruption and deactivation of trigger points in skeletal muscles. The purpose of this observational longitudinal clinical study was to determine the morphofunctional capacity of the masseter and temporalis muscles, and bite force in patients with temporomandibular disorders of muscular origin after DN of the masseter muscle. Twenty-one patients with the presence of trigger points in the masseter muscle were selected. Electromyographic activity of the masseter and temporalis muscles was assessed during the mandibular tasks of rest, protrusion, right and left laterality, and maximal voluntary contraction (MVC). Muscle thickness at rest and dental clenching at MVC was measured with ultrasound. Molar bite force (right and left) was analyzed with a digital dynamometer. Patients were evaluated before and seven days after intervention with DN. Data were subject to the paired t test for dependent samples (p<0.05). There was significant difference in the left masseter muscle in right laterality (p=0.01), right temporalis muscle thickness in MVC (p=0.05), and right (p=0.01) and left (p=0.008) molar bite force, after DN. The authors suggest that DN was efficient in the positive changes in the morphofunctional performance of the stomatognathic system. (AU)

A presença de pontos gatilhos miofasciais nos músculos mastigatórios pode gerar dor e estar relacionada à disfunção temporomandibular. A técnica de agulhamento a seco (AS) é utilizada para rompimento mecânico e desativação do ponto gatilho nos músculos esqueléticos. O objetivo deste estudo clínico longitudinal observacional foi determinar a capacidade morfofuncional dos músculos masseter e temporal, bem como a força de mordida, em pacientes com distúrbios temporomandibulares de origem muscular após AS no músculo masseter. Foram selecionados vinte e um pacientes com presença de pontos de gatilho no músculo masseter. A atividade eletromiográfica dos músculos masseter e temporal foi avaliada durante tarefas mandibulares de repouso, protrusão, lateralidade direita e esquerda, e contração voluntária máxima (CVM). A espessura muscular em repouso e a contração dental na CVM foram medidas por ultrassom. A força de mordida molar (direita e esquerda) foi analisada com um dinamômetro digital. Os pacientes foram avaliados antes e sete dias após a intervenção com DN. Os dados foram submetidos ao teste t pareado para amostras dependentes (p<0,05). Houve diferença significante no músculo masseter esquerdo na lateralidade direita (p=0,01), espessura do músculo temporal direito na CVM (p=0,05) e força de mordida molar direita (p=0,01) e esquerda (p=0,008), após AS. Os autores sugerem que o AS foi eficaz nas alterações positivas no desempenho morfofuncional do sistema estomatognático. (AU)

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Osteoarthrosis is a disorder of synovial joints, resulting from destruction of the cartilage and subchondral bone. The present study is aimed to investigate the molar bite force, thickness and efficiency of the masseter and temporalis muscles of subjects with osteoarthrosis. A total of forty-eight subjects participated in the study. They were distributed into two groups: with osteoarthrosis (n=24) and asymptomatic controls (n=24). Subjects were analyzed on the basis of maximal molar bite force (right and left side), thickness (mandibular rest and dental clenching in maximal voluntary contraction) and electromyographic activity of masticatory cycles through the linear envelope integral in habitual (raisins and peanuts) and non-habitual (Parafilm M) chewing of the masseter and temporalis muscles. All the data were analyzed statistically using t-test with a significance level of p≤0.05. There was no difference between groups in maximal molar bite force, muscle thickness and non-habitual chewing. Differences were found on the raisins (p=0.02) and peanuts (p=0.05) chewing for right temporal muscle, with reduced masticatory muscle efficiency in osteoarthrosis subjects. This study showed that osteoarthrosis induces negative changes in habitual chewing, highlighting the efficiency of the right temporalis muscles. The greater temporal muscle activity in subjects with osteoarthrosis may compromise chewing and consequently the nutritional status of adult subjects.

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BACKGROUND: Osteoarthrosis is a severe, evolutionary, chronic, and limiting disease that influences on quality of life, as it affects synovial joints and promoted degradation of hyaline articular cartilage. We sought to determine if electromyographic activity of the masticatory muscles and quality of life are negatively impacted by osteoarthrosis. MATERIAL AND METHODS: A sample of 72 participants between 40 and 70 years old diagnosed with osteoarthrosis were selected. Forty-eight participants met the inclusion criteria of this study and were divided into two distinct groups: with osteoarthrosis (n=24) and without osteoarthrosis (n=24). Electromyographic activity of the masseter and temporalis muscles (mandibular rest, right laterality, left laterality, protrusion, and dental clenching in maximal voluntary contraction) and quality of life measurements were used. Electromyographic activity was used to analyze muscle activation patterns. OHIP-14Br and SF-36 questionnaires determined the quality of life. RESULTS: The participants with osteoarthrosis presented significant greater electromyographic activity (p≤0.05) at rest for the right temporal muscle (p=0.04), maximum voluntary contraction for the left masseter muscle (P=0.04), repercussions of oral conditions on quality of life by the sum of OHIP-14 (p=0.002), and a statistically significant difference was found in all subgroups of the SF-36 scale between the subjects with and without osteoarthrosis (p≤0.001). CONCLUSIONS: People with osteoarthrosis have changes in electromyographic activity of the masticatory muscles and quality of life compared to healthy participants. Key words:Electromyography, quality of life, bone diseases.

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Impairing osteoporosis progression is a challenge, and recently the role of antioxidants has been associated to bone metabolism. Green tea extract is rich in catechins, especially epigallocatechin gallate (EGCG), which may help control osteoporosis damage in bone tissue. This investigation evaluated the efficacy of green tea ingestion containing different concentrations of EGCG in calvaria bone repair of ovariectomized rats. Wistar rats (n=15) were ovariectomized and divided into 3 groups: ovariectomized (OVX), ovariectomized + GTE 15 % EGCG (OVX/GTE15), and ovariectomized + GTE 94 % EGCG (OVX/GTE94). Green tea extract was administered by gavage in the concentration of 50 mg/kg and sham group (n=5) received water. Bone defects were performed in the calvaria 60 days after ovariectomy followed by 4 weeks until euthanasia. Bone samples were collected to perform qualitative and quantitative histological analysis of bone formation. Data obtained were submitted to normality and ANOVA statistical test for p<0.05. The mean values of neoformed bone for Sham, OVX, OVX/GTE15 and OVX/GTE94 were respectively: 21.11 ± 3.91; 19.92 ± 2.20; 33.05 ± 1.26 e 34.75 ± 0.54 (p<0.05). Results show that continuous ingestion of green tea extract immediately after ovariectomy shows positive effects in the prevention of bone loss in osteoporosis, even with low concentrations of EGCG.

La disminución en la progresión de la osteoporosis es un desafío, y recientemente el papel de los antioxidantes se ha asociado al metabolismo óseo. El extracto de té verde es rico en catequinas, especialmente el galato de epigalocatequina (EGCG), lo que puede ayudar a controlar el daño de la osteoporosis en el tejido óseo. Esta investigación evaluó la eficacia de la ingesta de té verde con diferentes concentraciones de EGCG en la reparación ósea de calvaria de ratas ovariectomizadas. Las ratas Wistar (n = 15) fueron ovariectomizadas y divididas en 3 grupos: ovariectomizadas (OVX), ovariectomizadas + GTE 15 % EGCG (OVX / GTE15), y ovariectomizadas + GTE 94 % EGCG (OVX / GTE94). El extracto de té verde se administró por sonda en una concentración de 50 mg/kg y el grupo simulado (n = 5) recibió agua. Los defectos óseos se realizaron en la calvaria 60 días después de la ovariectomía, seguido de 4 semanas hasta la eutanasia. Se obtuvieron muestras de hueso para realizar un análisis histológico cualitativo y cuantitativo de la formación ósea. Los datos obtenidos se sometieron a normalidad y prueba estadística ANOVA (p<0,05). Los valores medios de hueso neoformado para Sham, OVX, OVX / GTE15 y OVX / GTE94 fueron: 21,11 ± 3,91; 19,92 ± 2,20; 33,05 ± 1,26 y 34,75 ± 0,54 (p <0,05), respectivamente. Los resultados muestran que la ingesta continua de extracto de té verde, inmediatamente después de la ovariectomía, muestra efectos positivos en la prevención de la pérdida ósea ocurrida en la osteoporosis, incluso con concentraciones bajas de EGCG.

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OBJECTIVES: The objective of this study was to evaluate the electromyographic fatigue of the masseter and temporalis muscles in individuals with and without osteoporosis. METHODS: Median frequency of the initial, mid, and final periods of the electromyographic signal in the 33 subjects with osteoporosis (OG) and 33 subjects without osteoporosis [control (CG)] was analyzed. RESULTS: OG showed a decrease in median frequency along the electromyographic signal, with a significant difference for the right masseter: initial vs. mid periods, initial vs. final periods; left masseter: initial vs. final periods; temporal (right and left): initial vs. mid periods, initial vs. final periods, and mid vs. final periods. Percentage comparison of median frequency between the initial and mid periods and between initial and final periods in the OG showed a significant difference in the masticatory muscles. DISCUSSION: The findings suggest that osteoporosis is associated with changes in the function of masticatory muscles, especially when measured by electromyographic fatigue.

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PURPOSE: The present study evaluated electromyographic activity (EMG), masticatory performance, and tongue strength in children without and with orthodontic treatment needs. PATIENTS AND METHODS: A total of 90 children were screened and divided into the following groups: Group I (no treatment needed; mean age: 8.00 ± 0.43 years; n = 26), Group II (few malocclusions, treatment needed; mean age: 8.89 ± 0.43 years; n = 28), and Group III (slight-to-borderline treatment needed; mean age: 8.44 ± 0.22 years; n = 36). Orthodontic treatment need was classified on the basis of IOTN-DHC (Index of Orthodontic Treatment Need - Dental Health Component). The electromyographic Trigno EMG Systems was used for muscle analysis and the Iowa Oral Pressure Instrument (IOPI) was used to measure tongue strength. Data were analyzed using normality tests and one-way analysis of variance with a Bonferroni post hoc test (p ≤ 0.05). RESULTS: EMG in almost all mandibular movements was higher in Group III with statistically significant differences compared to position at rest: right masseter (p = 0.03); protrusion: left temporal (p = 0.02); saliva swallowing: left temporal (p = 0.05) and water swallowing: orbicularis oris mouth, right upper segment (p = 0.05). Lower masticatory performance was found in Group III, but the difference compared to Group I and II was not significant. There were no significant differences between the groups in terms of tongue strength. CONCLUSIONS: Children with borderline orthodontic treatment needs show functional disorders of the stomatognathic system.

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