Made available in DSpace on 2015-12-06T23:46:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2007 / Objetivo: Avaliar o músculo masseter em indivíduos portadores de esclerose sistêmica (ES), por meio da ressonância magnética, analisando a intensidade dos sinais em T1, T2 e a morfologia. Detectar, por meio da espectroscopia de hidrogênio, as alterações das concentrações de creatina, colina, lipídio e lactato no masseter, e relacionar com a presença de osteólise mandibular. Investigar as relações entre a osteólise mandibular com alguns parâmetros clínicos. Métodos: Foram selecionados 25 pacientes, 15 com diagnóstico de ES e 10 indivíduos normais: os pacientes com foram agrupados de acordo com a presença (grupo I) ou ausência (grupo II) de osteólise de mandíbula. Os indivíduos normais perfizeram o controle (grupo III). Todos foram submetidos a exame de ressonância magnética, em aparelho Siemens modelo Sonata®, com campo magnético de 1,5T e gradiente de 40mT, onde foram adquiridas seqüências TSE ponderadas em T2 no plano coronal e T1 no plano axial, com e sem supressão de gordura; a concentração dos me tabólitos foi avaliada pela espectroscopia de prótons com técnica PRESS e aquisição tridimensional. Resultados: Não houve diferença entre o sinal T1 de RM nos grupos I e II (p=0,295). O grupo II apresentou maior intensidade do sinal T2 em relação ao grupo III (p=0,033), porém não houve diferença em relação ao grupo I. O estudo dos metabólitos dos três grupos apresentou os mesmos valores absolutos de creatina (p=0,424) e lipídio (p=0,966), enquanto que os pacientes do grupo I apresentar am maior quantidade de colina em relação ao grupo III (p=0,108). Já os grupos I e II apresentaram menor quantidade de lactato em relação aos indivíduos normais (p=0,001). Os índices creatina/ lipídio (p=0,314) e colina/ lactato (p=0,790) foram estatisticamente os mesmos em todos os grupos. Por outro lado, os demais índices mostraram variações significantes, a saber: creatina/ colina (p<0,001), creatina/ lactato (p=0,019), lipídio/ lactato (p=0,005) e colina/ lipídio (p=0,004). O estudo morfológico mostrou que grupos I e II apresentaram mais atrofia (p=0,004), substituição gordurosa (p=0,018) e morfologia retificada (p=0,017) em relação aos indivíduos normais, porém não existiu diferença de simetria entre os normais e os doentes (p=0,236). O grupo I apresentou maior tempo de doença em relação ao grupo II (p=0,003). Os grupos I e II apresentaram a mesma abertura média de boca. Existe uma correlação crescente entre abertura de boca e tempo de doença no grupo I (p=0,095), que não ocorre no grupo II (p=0,596). Não houve relação entre a presença de dentes e a presença de osteólise (p>0,999), e entre a presença de dentes e o lado da osteólise (p=0,143). Conclusão: O masseter está afetado nos pacientes com ES, independente da presença ou não da osteólise. Em relação aos metabólitos, observamos menor quantidade de lactato, enquanto que a colina mostrou-se aumentada na osteólise. A osteólise parece se desenvolver em pacientes com maior tempo de doença, porém não modificou no grau de abertura bucal em relação aos pacientes sem osteólise, e a presença de dentes não foi significante. Por outro lado, nos casos de osteólise, quanto maior o tempo de doença maior a abertura bucal. / Objective: to evaluate the masseter muscle in systemic sclerosis (SS) patients by magnetic resonance (MR), regarding the intensity of T1 and T2 tissue signal and the morphology; to detect, by the proton magnetic resonance spectroscopy, the abnormalities of the creatine, choline, lipids and lactate’s concentration in the masseter, and correlate with the mandibular osteolysis; to investigate the correlations of the mandibular osteolysis with some clinical findings. Methods: 25 subjects were selected, 15 with PSS diagnosis and 10 healthy controls. The patients were gathered in concordance with the presence (group I) or absence (group II) of the mandibular osteolysis. The healthy subjects performed the control (group III). All of them were submitted of the magnetic resonance scan, on a 1,5T MR imager Siemens Sonata®, 40mT gradient, and images were obtained in T2 coronal scans and T1 axial scan, with and without fat suppression technique. The metabolits concentration were evaluated by the proton magnetic resonance spectroscopy with PRESS technique and tridimensional acquisition. Results: the study showed no difference between MR T1 signal in the groups I and II (p=0,295). The group II showed increased of MR T2 signal regarding group III (p=0,033), but there was no difference by group I. The metabolic study of the three groups showed the same absolute values of the creatine (p=0,424) and lipids (p=0,966), whereas the group I subjects showed high content of choline regarding the group III (p=0,108). The groups I and II showed low content f the lactate regarding the healthy subjects (p=0,001). The creatine/lipid ratio (p=0,314 ) and choline/lactate ratio (p=0,790) were the same in all groups. Otherwise, the others ratios showed variations: creatine/choline (p<0,001), creatine/lactate (p=0,019), lipid/lactate (p=0,005) and choline/lipid (p=0,004). The morphological analysis showed more atrophy in the groups I and II (p=0,004), fatty replacement (p=0,018) and ratified morphology (p=0,017) regarding the healthy subjects, but there was no difference about symmetry among the diseases and healthy group (p=0,236). The group I showed more duration of disease regarding the group II (p=0,003). The groups I and II showed the same mouth opening. There is a correlation among mouth opening and duration of disease in the group I (p=0,095), this result was not observed in the group II (p=0,596). There was no correlation among the absence of the teeth and osteolysis (p>0,999), and among the absence of the teeth and side of the osteolysis (p=0,143). Conclusions: the masseter was affected in SS patients, and it no depends of the osteolysis. Regarding the metabolic changes, we observed low concentration of lactate and high concentration of choline in osteolysis’ patients. The osteolysis seems to develop in more duration of disease patient, but did not modified the mouth opening regarding patients without osteolysis, and the presence of the teeth was not signified. Otherwise, in the osteolysis subjects, we observed that if more duration of disease, more mouth opening. / BV UNIFESP: Teses e dissertações

Made available in DSpace on 2014-06-11T19:35:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-19Bitstream added on 2014-06-13T20:25:49Z : No. of bitstreams: 1 gallo_akg_dr_araca.pdf: 2876944 bytes, checksum: 2ff745257f492f78b142834982595d1b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O esforço muscular exige modificações metabólicas e uma adaptação, ou seja, uma necessidade maior de nutrientes e O2 para que seja realizada a contração muscular. O objetivo do presente estudo foi verificar o efeito do tempo de mastigação sobre o período de silêncio, limiar de sensibilidade e atividade elétrica dos músculos masseter e temporal anterior. Conclui-se que: 1) em relação ao período de silêncio, houve diferença entre os gêneros, porém, a duração da atividade mastigatória não produziu diferença 2) o LDP apresentou diferenças estatisticamente significantes entre os músculos masseter direito e músculo temporal esquerdo. Porém estes músculos não apresentaram diferenças significantes em relação aos demais. Entre os gêneros, o LDP também não apresentou diferenças significativas 3) que entre os gêneros o LDP foi menor no gênero feminino havendo diferença somente para o músculo masseter. Contudo, a atividade mastigatória dentro do tempo estudado, não levou a alterações no LDP 4) que não houve diferença estatisticamente significante entre as médias das atividades elétricas entre os gêneros analisados. Porém o tempo de mastigação do látex foi um fator significativo para alterações das atividades elétricas dos músculos masseter e temporal do lado de trabalho / The muscular effort demands metabolic modifications and an adaptation, in other words, a larger need of nutrients and O2 so that the muscular contraction is accomplished. The objective of the present study was to verify the effect of the time of mastication on the silence period, sensibility threshold and electric activity of the muscles masseter and previous storm. It is ended that: 1) in relation to the silence period, there was difference among the goods, however, the duration of the activity masticatory didn't produce difference 2) LDP presented differences significant between the muscles right masseter and left temporary muscle. However these muscles didn't present significant differences in relation to the others. Among the goods, LDP didn't also present significant differences 3) that enters the goods LDP was smaller in the feminine gender having only differentiates for the muscle masseter. However, the activity masticatory inside of the studied time, it didn't take to alterations in LDP 4) that there was not differentiates significant among the averages of the electric activities among the analyzed goods. However the time of mastication of the latex went a significant factor to alterations of the electric activities of the muscles masseter and storm beside work

A major physiological risk factor of temporomandibular disorders (TMD) is sensitization of peripheral and central nervous system pain processing pathways. Calcium channel, voltage-dependent, alpha-2/delta subunit-1 (CACNA2D1) has a crucial role in relaying nociceptive information in the spinal dorsal horn. Up-regulation of CACNA2D1 results in abnormal excitatory synapse formation and enhanced presynaptic excitatory neurotransmitter release. Blocking CACNA2D1 with gabapentinoid-class drugs relieves orofacial hypersensitivity. Drs. Foley, Horton, and Sciote previously reported that in a small sample group (n=12), CACNA2D1 expression was greater in males than females, but increased in women with TMD. The objectives of this study are to corroborate these data and investigate expression patterns of other ion channel and conducting system genes. Additionally, since the null polymorphism ACTN3-577XX associates with muscle fiber microdamage during eccentric contraction, we tested for possible gene associations with ACTN3-R577XX genotypes. Masseter muscle samples came from human subjects (n=23 male; 48 female) with malocclusions undergoing orthognathic surgery. This population had skeletal disharmony of the jaws and thus was prone to eccentric contraction. Three males and eighteen females were diagnosed with localized masticatory myalgia. Muscle total RNA was isolated and CACNA2D1, CACNA1S, GABARAP, and TRPM7 expression was quantified using RT-PCR. Expression of these genes were compared based on TMD status and various characteristics that may influence TMD including: sex, age, facial symmetry, sagittal dimension, vertical dimension, ACTN3-577 genotype and fiber type. CACNA2D1 expression differed significantly between sexes, overall (p&lt;0.02), and without TMD (p=0.001). Women with (n=13) and without (n=23) TMD differed significantly (p&lt;0.03). CACNA2D1 expression was also significantly higher (p=0.031) in subjects below age 25. Similarly, GABARAP expression was significantly higher (p=0.001) for patients younger than 25 and for patients less than or equal to age 18 (p=0.013). Otherwise, CACNA1S, TRPM7 and GABARAP differences were not significant. GABARAP expression differed, but not significantly by sex and for the ACTN3-577XX-null genotype. In a population of malocclusion patients, masseter muscle CACNA2D1 expression is significantly higher than CACNA1S, TRPM7, and GABARAP. CACNA2D1 expression is greater in males than females without TMD. However, CACNA2D1 expression increases significantly in females with TMD-associated myalgia. This may support evidence for calcium channel regulation of nociception differences seen between sexes in TMD. It was also found that expression of CACNA2D1 and GABARAP is significantly higher in younger subjects. Additionally, observations presented here suggest potential influence of ACTN3-null condition on function of GABARAP. / Oral Biology

Significant advances have been made in orthodontics and oral maxillofacial surgery for the diagnosis and treatment of dentofacial deformities. However, compared with bone, the effect of muscles of the craniofacial complex in the development of dentofacial deformities has received little attention. Recently, cellular and molecular studies of the musculoskeletal interactions have been used to investigate the etiology of dentofacial malocclusions. In this study, we tested for relationships that might exist between gene expression of the chromatin modifying enzymes histone deacetylase-4 (HDAC4) and histone acetyltransferase-4 (MYST4) and expression of myosin heavy chain (MyHC) genes and fiber-type percent occupancy (%Occ) in masseter muscle of patients undergoing orthognathic surgery to correct severe dentofacial malocclusions. The diagnostic categories of malocclusion in sagittal and vertical dimensions were: 1) Deep bite-Class II (D2); 2) Deep bite-Class III (D3); 3) Normal bite-Class II (N2); 4) Normal bite-Class III (N3), 5) Open bite-Class II (O2); 6) open bite with Class III (O3). Relative quantities (RQs) of gene expression were determined by reverse transcriptase real time polymerase chain reaction (RT-PCR) in RNA extracts of masseter samples, previously analyzed by immunohistochemistry for %Occ values. By multivariate analysis, RQs of HDAC4 and MYST4 expression did not differ significantly between malocclusion types. However, multiple high positive and negative correlations were found for HDAC4 and MYST4 with MyHC expression and with fiber type %Occ. Significant correlations occurred for HDAC4 with: IIX and neonatal MyHCs respectively in N2 and N3 subjects; fiber types I, I/II and neonatal/atrial %Occ respectively in D2 and N3, D2 and O3 subjects. Further investigations are needed to support evidence of these correlations and determine their significance toward diagnosis, treatment and relapse potential in the correction of dentofacial deformities. / Oral Biology

Objective: Obstructive sleep apnea (OSA) is defined by recurrent breathing cessations accompanied by a collapse of the pharyngeal airway. Co-morbid conditions include obesity, cardiovascular disease, diabetes, and in some cases, retrognathia and muscle dysfunction. The latter two conditions may prompt orthognathic correction. Past investigations have shown a genetic association with OSA. Given that masseter muscle influences skeletal malocclusion and is active during OSA, we investigated whether the expression of OSA-associated genes is altered in a Class II open bite OSA subject. Methods: Eleven mandibular advancement surgery patients were classified as skeletal Class II or III and open or deep bite malocclusion, including a Class II open bite patient with OSA. Masseter muscle samples were collected at surgery and frozen. Tissue was used for gene expression analysis on Affymetrix HT2.0 microarray chips and quantitative RT-PCR. Data for ten genes associated with OSA were individually evaluated in the microarray and compared between the OSA patient and eight symmetrical malocclusion subjects. In order to corroborate these expression data, one gene of interest, tumor necrosis factor (TNF), was quantified in the ten malocclusion subjects from the microarray, an OSA subject from the microarray and one additional OSA subject by RT-PCR. Results: Among OSA-associated genes on the microarray, interleukin genes IL1B, IL1R2, IL6 and IL8 were +2.5 to +9.2 fold greater (p &lt; 0.02) and chemokine genes CCL2, CCL3, CCL3L3, CCL4 and CXCR1 were +2.0 to +12.1 fold greater (p &lt; 0.05). Likewise, TNF expression differed significantly in the muscle of the OSA subject (+2.2 fold greater; p &lt; 0.001). By quantitative RT-PCR, TNF expression was significantly greater in malocclusion subjects with OSA compared to those without OSA (p = 0.0004). Conclusions: Our findings support evidence that OSA is an inflammatory disorder, which may elicit hypoxia-induced inflammatory responses believed to promote skeletal muscle dysfunction. Specifically, we report that inflammatory gene expression is significantly increased in masseter muscle in Class II open bite subjects with OSA. In turn, malocclusion may contribute to OSA, which negatively affects masseter function, resulting in exacerbation of both disorders. Because OSA is reported to associate with a polymorphism in the TNF-alpha; gene in children, future studies are needed to test for similar genetic associations in malocclusion subjects with OSA. / Oral Biology

Os objetivos do presente estudo foram analisar os efeitos do tratamento de pacientes com Desordem temporomandibular (DTM) articular crônica com a placa interoclusal estabilizadora modelo Michigan por meio dos índices eletromiográficos POC dos temporais, POC dos masseteres, TORS, ASSIM, Ativação, Ativação absoluta, TORQUE, Impacto, em máximo apertamento dental voluntário (MCV) em máxima intercuspidação habitual (MIH) e máximo apertamento voluntário com algodão entre os dentes (MAA). Foram também analisados os sinais e sintomas de DTM. Participaram do estudo 20 sujeitos, jovens e adultos, sendo 10 com DTM articular crônica, que receberão tratamento com placa oclusal modelo Michigan (Grupo DTM) e 10 sujeitos sem sinais e sintomas de DTM (Grupo Controle). Os sujeitos passarão por exame clínico e responderão ao Protocolo para Determinação dos Sinais e Sintomas de DTM para Centros Multiprofissionais (Felício et al., 2006). Os registros e cálculos dos índices eletromiográficos serão realizados com o Eletromiógrafo Freely de oito canais (De Götzen srl; Legano, Milano, Italy). Foram comparados os dados do grupo DTM na fase de diagnóstico (FD) e na fase final (FF) de tratamento, bem como os dados deste grupo com os do grupo controle. Para os dados expressos em nível intervalar de mensuração, como os dos exames clínicos, foi empregada estatística não-paramétrica. Os dados em nível de razão, isto é os dados eletromiográficos, foram analisados por meio de estatística paramétrica. O nível de significância estabelecido foi de 5%. / The objectives of this study were to analyze the effects of treatment of patients with temporomandibular disorder (TMD) joint with chronic plaque-stabilizing model interocclusal Michigan through electromyographic indices of temporal POC, the POC masseter, TORS, SO, Activation, Activation absolute TORQUE, Impact, for maximum voluntary tooth clenching (MCV) in maximum intercuspal usual (MHI) and maximum voluntary clenching with cotton between teeth (MAA). We also analyzed the signs and symptoms of TMD. The study included 20 subjects, young people and adults, and 10 with chronic articular TMD, which would be treated with occlusal splints Michigan model (DTM Group) and 10 subjects without signs and symptoms of TMD (control group). The subjects will undergo clinical examination and respond to the Protocol for the Determination of the signs and symptoms of TMD for multi Centers (Felicio et al., 2006). Records and calculations of indices electromyographic out with the electromyograph Freely eight channels (De Götzen srl; Legano, Milano, Italy). We compared the data from the DTM group stage of diagnosis (FD) and the final stage (FF) treatment, as well as data from this group with the control group. For data expressed as interval level of measurement, such as clinical examination, was used non-parametric statistics. Data on level of reason, ie electromyographic data were analyzed using parametric statistics. The significance level was set at 5%.

Background: Registering a true maximum bite force on the most commonly-used force transducers is problematic. It is often believed that this is related mainly to discomfort and the fear of breaking teeth. Objectives: The aim of the project was to compare the suitability of different bite force measuring transducers including ones which were designed to improve subject comfort. The transducers used were a traditional strain-gauge transducer with and without covering with ethylene vinyl acetate (EVA) sheets, and a newly-developed pressure transducer. Methods: Five separate studies were performed in this project. The experiments were carried out on human volunteer subjects (aged 24 to 41 years). They were all dentate with no missing anterior teeth and with no crowns on these teeth. The following procedures were used in some or all of the studies: measurement of MVBF, electrical stimulation of the masseter muscle, and EMG recording from two pairs of jaw closing muscles. Results: The highest MVBF values were recorded on the pressure transducer, mean (± S.D.) 464 N ± 224 N; followed by the strain-gauge transducer with EVA sheets, 243 ± 80 N; and last of all the strain-gauge transducer with silicone indices, 165 ± 35 N; or acrylic indices, 163 ± 82 N. Significantly higher maximum potential bite forces were predicted by twitch interpolation for the pressure transducer (730 ± 199 N) than for the strain-gauge transducer with EVA sheets, 354 ± 67 N (Paired t test, P < 0.05). Significantly higher EMGs of the masseter and anterior temporalis muscles were found to be associated with MVBFs on the pressure transducer than with MVBFs on the strain-gauge transducer with EVA sheets (Paired t test, P < 0.05). Conclusions: It is concluded that: a) the pressure transducer system and to a lesser extent the strain-gauge transducer covered with EVA sheets seemed to overcome the fear associated with biting on the hard surfaces of the strain-gauge transducer alone; b) the pressure transducer may have some multi-directional capabilities which allow for total bite forces, or at least larger parts of them, to be recorded than on a uni-directional strain-gauge transducer.

Made available in DSpace on 2014-06-11T19:28:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-16Bitstream added on 2014-06-13T18:35:14Z : No. of bitstreams: 1 pita_ms_me_araca.pdf: 1127223 bytes, checksum: 58ceb27b15fa47637a76872acfa04d3e (MD5) / O aumento da atividade muscular, induzido pelo apertamento dental, pode ser considerado como fator etiológico ou agravante das desordens temporomandibulares (DTMs), e essa atividade tem sido explorada de maneira direta através da eletromiografia e indiretamente pela variação da temperatura superficial cutânea sobre os músculos mastigatórios. As placas oclusais são os métodos não-invasivos mais utilizados para o tratamento das DTMs, particularmente as que afetam os músculos mastigatórios, objetivando a redução dessa hiperatividade muscular. Entretanto, há controvérsias em relação ao estabelecimento da sua espessura ideal. O objetivo do presente estudo, foi determinar o efeito da espessura de placas miorrelaxantes (3 mm e 6 mm) sobre a atividade elétrica e a temperatura dos músculos temporal anterior e masseter durante o repouso e o apertamento dental, considerando-se a condição assintomática de 20 indivíduos (10 homens e 10 mulheres) selecionados através do questionário Research Diagnostic Criteria (RDC). Os registros eletromiográficos foram realizados por meio do software “Bio EMG” (Biopack – System Bio-Research) e a temperatura das superfícies musculares realizada com o auxílio de um termômetro digital infravermelho (ICEL TD-971), com as respectivas medidas em microvolts ([V) e graus Celsius (ºC). Os resultados obtidos, analisados estatisticamente em um nível de 5% de significância (p<0,05), evidenciaram o aumento da atividade elétrica e a diminuição da temperatura dos músculos temporal anterior e masseter durante o apertamento dental em relação ao repouso. Entretanto não houve diferenças estatisticamente significativas em relação à atividade elétrica e a temperatura dos músculos mastigatórios entre as condições com e sem placa, entre o gênero masculino e feminino, bem como entre as espessuras de placas analisadas. / The increased of muscles activity, induced for dental clenching can be considered as causing or aggravating factor of temporomandibular disorders (TMD), and this activity has been exploited in a straightforward manner using electromyography and indirectly by the variation in skin surface temperature on the masticatory muscles. The occlusal splints are non-invasive methods more utilized for the treatment of TMD, particularly those from the masticatory muscles, aiming at the reduction of muscle hyperactivity. However, there are controversies regarding the establishment of their ideal thickness. The aim of this study was to determine the effect of thickness of the occlusal splints (3 mm and 6 mm) on the electrical activity and temperature of the anterior temporal and masseter muscles during dental clenching and resting, considering the asymptomatic condition of 20 individuals (10 males and 10 females) selected through the questionnaire Research Diagnostic Criteria (RDC). The electromyographic data were analyzed by the software Bio EMG (Biopack - Bio-Research System) and the surface temperatures of muscle carried out with the aid of a digital infrared thermometer (ICEL TD-971) and the corresponding measures in microvolts ([V) and degrees Celsius (ºC). The results, analyzed in a 5% of significance (p <0.05), showed increased electrical activity and lowering the temperature of the anterior temporal and masseter muscles during dental clenching in relation to the rest. However there were no statistically significant differences in relation to temperature and electrical activity of masticatory muscles between conditions with and without splints, between males and females, and between the thicknesses of occlusal splints analyzed.

Orientador: Marcos Rogério de Mendonça / Banca: Osmar Aparecido Cuoghi / Banca: Paulo Cesar Tukasan / Resumo: O objetivo deste estudo foi avaliar a atividade eletromiográfica dos músculos masseter e temporal anterior em crianças com mordida cruzada posterior unilateral funcional. A amostra foi composta por 8 crianças com idade de 5 a 10 anos, um menino e sete meninas que não apresentavam hábitos parafuncionais, sintomas neuromusculares como dor ou fadiga e disfunção temporomandibular. As análises eletromiográficas foram realizadas nestes músculos na posição de repouso, máximo apertamento dentário na posição de máxima intercuspidação e durante a mastigação no lado da mordida cruzada e no lado não cruzado, antes (T1) e após (T2) o tratamento da mordida cruzada posterior unilateral funcional com a utilização do aparelho ortodôntico quadrihélice. Os resultados mostraram uma diferença significante somente para o músculo temporal anterior do lado da mordida cruzada para a posição de repouso, mas houve uma tendência para um aumento no temporal anterior do lado não cruzado e para o masseter do lado cruzado, enquanto houve uma diminuição no masseter do lado não cruzado. Durante o apertamento dentário na posição de máxima intercuspidação, todos os músculos monstraram uma tendência ao aumento da atividade eletromiográfica. Durante a mastigação, houve uma tendência para diminuir a atividade em todos os músculos, exceto para o temporal anterior do lado da mordida cruzada, que registrou um aumento. / Abstract: The purpose of this study was to evaluate the electromyographic activity of masseter and anterior temporal muscles in children with unilateral functional posterior crossbite. The sample was compounded of 8 children aged 5 to 10 years, one boy and seven girls that not present parafunctional habits, neuromuscular symptoms referring to pain or fadigue and temporomandibular disfunction. Electromyographic evaluations were carried out in these muscles at rest position, maximal bite in the intercuspal position and during chewing on the crossbite side and on the noncrossbite side, before (T1) and after (T2) unilateral functional posterior crossbite treatment by using quadhelix orthodontic appliance. The results showed significant difference only for anterior temporal muscle on the crossbite side at rest position, but there was tendency to increase in the anterior temporal on the noncrossbite side and in the masseter on the crossbite side, while there was a decrease in masseter on the noncrossbite side. During maximal bite in the intercuspal position before treatment, all muscles showed a tendency to increase the electromyograpihc activity. During chewing, there was a tendency for decrease activity in all muscles, except for anterior temporal on the crossbite side, that registered an increase. / Mestre

Os objetivos do presente estudo foram analisar os efeitos do tratamento de pacientes com Desordem temporomandibular (DTM) articular crônica com a placa interoclusal estabilizadora modelo Michigan por meio dos índices eletromiográficos POC dos temporais, POC dos masseteres, TORS, ASSIM, Ativação, Ativação absoluta, TORQUE, Impacto, em máximo apertamento dental voluntário (MCV) em máxima intercuspidação habitual (MIH) e máximo apertamento voluntário com algodão entre os dentes (MAA). Foram também analisados os sinais e sintomas de DTM. Participaram do estudo 20 sujeitos, jovens e adultos, sendo 10 com DTM articular crônica, que receberão tratamento com placa oclusal modelo Michigan (Grupo DTM) e 10 sujeitos sem sinais e sintomas de DTM (Grupo Controle). Os sujeitos passarão por exame clínico e responderão ao Protocolo para Determinação dos Sinais e Sintomas de DTM para Centros Multiprofissionais (Felício et al., 2006). Os registros e cálculos dos índices eletromiográficos serão realizados com o Eletromiógrafo Freely de oito canais (De Götzen srl; Legano, Milano, Italy). Foram comparados os dados do grupo DTM na fase de diagnóstico (FD) e na fase final (FF) de tratamento, bem como os dados deste grupo com os do grupo controle. Para os dados expressos em nível intervalar de mensuração, como os dos exames clínicos, foi empregada estatística não-paramétrica. Os dados em nível de razão, isto é os dados eletromiográficos, foram analisados por meio de estatística paramétrica. O nível de significância estabelecido foi de 5%. / The objectives of this study were to analyze the effects of treatment of patients with temporomandibular disorder (TMD) joint with chronic plaque-stabilizing model interocclusal Michigan through electromyographic indices of temporal POC, the POC masseter, TORS, SO, Activation, Activation absolute TORQUE, Impact, for maximum voluntary tooth clenching (MCV) in maximum intercuspal usual (MHI) and maximum voluntary clenching with cotton between teeth (MAA). We also analyzed the signs and symptoms of TMD. The study included 20 subjects, young people and adults, and 10 with chronic articular TMD, which would be treated with occlusal splints Michigan model (DTM Group) and 10 subjects without signs and symptoms of TMD (control group). The subjects will undergo clinical examination and respond to the Protocol for the Determination of the signs and symptoms of TMD for multi Centers (Felicio et al., 2006). Records and calculations of indices electromyographic out with the electromyograph Freely eight channels (De Götzen srl; Legano, Milano, Italy). We compared the data from the DTM group stage of diagnosis (FD) and the final stage (FF) treatment, as well as data from this group with the control group. For data expressed as interval level of measurement, such as clinical examination, was used non-parametric statistics. Data on level of reason, ie electromyographic data were analyzed using parametric statistics. The significance level was set at 5%.