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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Avaliação da influência da força de mordida na prótese parcial removível classe I mandibular associada ao implante osseointegrado, pelo método dos elementos finitos /

Lucas, Liliana Vicente Melo de. January 2003 (has links)
Orientador: Eduardo Piza Pellizzer / Resumo: A associação entre as próteses parciais removíveis e os implantes osseointegrados é, ainda, uma opção de tratamento muito pouco explorada na Odontologia reabilitadora moderna. Por isso, o objetivo deste estudo é avaliar, utilizando o método dos elementos finitos bidimensional, a distribuição de tensão nas estruturas de suporte da prótese parcial removível de extremidade livre (PPREL) associada a um implante osseointegrado de 10,0 x 3,75 mm (Sistema Branemark), localizado na região posterior do rebordo alveolar desdentado, atuando como suporte para a base da prótese. Para tanto, foram criados três modelos, os quais, em corte sagital, representam: modelo A (MA) - hemiarco contendo o dente natural 33 somente e o A rebordo desdentado distal; modelo B (MB) - semelhante ao MA, com uma PPREL convencional substituindo os dentes ausentes; modelo C (MC) - semelhante ao anterior, com um implante na região posterior do rebordo, sob a base da prótese. Com o auxílio do programa de elementos finitos ANSYS 5.4, os modelos foram carregados com forças verticais e oblíquas de 45º, tanto no sentido de mesial para distal como no sentido inverso, de magnitude de 50 N, em cada ponta de cúspide. A análise dos mapas de tensões permitiu concluir que: 1) a tendência de deslocamento no modelo com a PPR apoiada sobre implante é menor que no modelo com a prótese somente; 2) as forças oblíquas de 45º promovem uma tendência de deslocamento e valores de tensão maiores que a força vertical; 3) a força oblíqua de 45º, no sentido de mesial para distal, gera valores de tensão menores que a de distal para mesial e 4) a presença do implante osseointegrado, sob a base da prótese, promove alívio do dente suporte. / Abstract: The association among the removable partial dentures and the osseointegrated implants is still a non very explored option of treatment in the modern prosthetic dentistry. Because of this, the objective of this study is to evaluate, using the two-dimensional finite element analysis, the tension distribution in the support structures of the distal extension removable partial denture (RPD) associated with a 10.0 x 3.75 mm osseointegrated implant (Branemark System), located in the posterior area of the toothless alveolar edge, acting as support for the prosthesis base. Then, three plane strain models were created, represented in sagital cut: Model A (MA) - hemiarc containing the natural tooth 33 and the toothless alveolar edge; Model B (MB) - similar to MA, with a conventional RPD substituting the absent teeth; Model C (MC) - similar to the previous, with an implant in the posterior area of the edge, under the denture base. With the aid of the finite element program ANSYS 5.4, the models were loaded with vertical and 45º inclined forces, in both mesial and distal sides, with 50 N, on each peak point. The analysis of the tensions map allowed to conclude that: 1) the displacement tendency in the model with the RPD supported by the implant is smaller than the model with prosthesis only; 2) the oblique forces of 45º promote a displacement tendency and larger tension values than the vertical force; 3) the mesial to distal 45º oblique force generates smaller tension values than the one of distal to mesial and 4) the presence of the osseointegrated implant, under the denture base, promotes relief to the support tooth. / Mestre
102

Agressão humana e marcas de mordidas: a vulnerabilidade de mulheres e crianças / Human aggression and bite marks: the vulnerability of women and children

Fernanda Bruni Queiroz 07 December 2010 (has links)
Este trabalho apresenta os resultados de um estudo sobre o comportamento agressivo humano, enfatizando as diversas implicações das marcas de mordidas produzidas por agressores e vítimas, notadamente quando se trata de estupro ou violência sexual, violência doméstica e abuso sexual. Essas ocorrências costumam acontecer em espaços domésticos/privados, pressupondo, portanto, um contato direto, físico, entre agressores e vítimas, que se situam em posições assimétricas, pois os primeiros, em geral homens adultos, ameaçam e brutalizam mulheres e crianças, frequentemente mais fracas e vulneráveis, física e socialmente. A violência produz impactos incomensuráveis no sistema público de saúde e na sociedade em geral, mas primordialmente em suas incontáveis vítimas. Entretanto, os crimes tidos como mais sérios e ameaçadores são aqueles cometidos mediante o uso de armas de fogo ou armas brancas, entre pessoas simétricas (homens adultos) e mais comuns em ambientes públicos. As ocorrências que têm lugar no cenário doméstico, quando as vítimas são mulheres e crianças, não são levadas tão a sério (e, por isso, mais toleradas e negligenciadas), o que acarreta a subnotificação desses crimes e um subcomparecimento das vítimas aos órgãos jurídicos e policiais, entre os quais se encontram os IMLs, que se ocupam dos exames de corpo de delito. Os dados avaliados neste estudo procedem de múltiplas fontes: literatura acadêmica especializada, matérias jornalísticas, notícias compiladas no Arquivo Digital da Folha de S. Paulo, informações registradas em Relatórios elaborados pelo IML/Sede do município de São Paulo e imagens disponíveis no Google imagens / This paper presents the results of a study on human aggressive behavior, emphasizing the various implications of bite marks produced by aggressors and victims, especially when it comes to rape or sexual assault, domestic violence and sexual abuse. These events usually take place in domestic spaces / private, assuming, therefore, a direct, physical, between aggressors and victims, which are located in asymmetric positions, because the former generally adult men, threaten and brutalize women and children, often more weak and vulnerable, physically and socially. Violence produces immeasurable impact on the public health system and society in general, but primarily in its countless victims. However, the crimes considered most serious and threatening are those committed by the use of firearms or knives, among people symmetric (adult men) and more common in public places. The events that take place in the domestic arena, where the victims are women and children, are not taken as seriously (and therefore more tolerated and neglected), which leads to underreporting of these crimes and a sub-attendance of the victims to legal and law enforcement agencies, among which are the IMLS, dealing with a forensic examination. The data evaluated in this study come from multiple sources: specialized academic literature, journalistic articles, reports compiled in the Digital Archive of the Folha de S. Paul, information recorded in reports prepared by the IML / Headquarters in São Paulo and images available on Google images
103

Influência da inclinação do garfo de mordida do arco facial na montagem do modelo superior em articulador semi-ajustável do tipo arcon e não-arcon / Influence of the inclination of the face-bow\'s bite fork on mounting of maxillary cast in arcon and nonarcon semiadjustable articulators

Daniele Manfrim Bellodi 15 August 2008 (has links)
Durante o processo ensino/aprendizagem em Odontologia, é comum a ocorrência de inclinações do garfo de mordida em relação ao plano oclusal maxilar dos pacientes durante a tomada do arco facial realizada por alunos. Este trabalho avaliou a influência das inclinações do garfo de mordida para anterior e para posterior em relação ao plano oclusal na montagem do modelo maxilar em articuladores semi-ajustáveis do tipo arcon e não-arcon. Foram obtidos vinte modelos do arco maxilar de vinte pacientes, nos quais dois pontos foram marcados: um na aresta vestibular do canino direito e outro na aresta vestibular da cúspide mésio-vestibular do primeiro molar direito. Os registros no garfo de mordida foram realizados em três posições: garfo de mordida paralelo ao plano oclusal dos modelos, inclinado para anterior e para posterior (ambas 5º). Cada posição foi repetida cinco vezes, sendo o conjunto articulador/arco facial fixado em suporte especial para registro fotográfico. Cada fotografia foi levada ao programa Auto CAD, obtendo-se linhas de referências para a coleta de cinco medidas (uma angular e quatro lineares). Os dados obtidos foram submetidos à análise estatística paramétrica (Análise de Variância). Os resultados indicaram não haver diferença estatisticamente significante para inclinações do garfo de mordida tanto para anterior como para posterior em relação ao plano oclusal do modelo tanto para o articulador semi-ajustável do tipo arcon como para o não-arcon. O trabalho sugere que pequenas inclinações do garfo de mordida não comprometem a tomada do arco facial e sua transferência para articuladores semi-ajustáveis. / During the process teaching/learning in Dentistry, the occurrence of adverse inclinations of the bite fork concerned to maxillary occlusal plane of patients are current during the face-bow taking performed by students. This study evaluated the influence of the inclinations of bite fork to anterior and posterior related to oclusal plane on mounting of the maxillary cast in arcon and nonarcon semiadjustable articulators. Twenty casts of the maxillary arch from twenty patients were obtained, on which two points were marked: one on the vestibular edge of the right canine and another on the vestibular edge of mesiovestibular cusp of the right first molar. The records in the bite fork were made in three positions: the bite fork parallel to the castss plane occlusal, inclined to anterior and to posterior (both 5°). Each position was repeated five times, being the articulator/face-bow set fixed in special support for photographic register. Each photograph was introduced in Auto CAD program, resulting in lines of references for the collection of five measures (one angular and four linear). The data were subjected to statistical analysis parametric (Analysis of Variance). The results showed no significant statistical difference for inclinations of the bite fork to both anterior and to posterior related to the castss occlusal plane for the arcon and nonarcon semiadjustable articulators. The work suggests that small inclinations of bite fork do not compromise the face-bow taking and its transfer for the semiadjustable articulators.
104

Mechanical monitoring of inhibitory jaw reflexes in health and simulated dysfunction

Atassi, Mounir January 2014 (has links)
Objectives: Previous studies in the Oral Neurophysiology Laboratories in Dundee have defined the electromyographic properties of the inhibitory jaw reflex that can be evoked in human subjects by electrical stimulation of the lip. This reflex, in contrast with the more widely studied biphasic inhibitory reflexes evoked by stimulation of intra-oral nerves, consists of just a single phase of inhibition and usually requires the application of stimuli which excite nociceptive nerves. The aims of the present studies were to define the mechanical manifestations of this reflex in the form of changes in biting forces, and to investigate whether the mechanical manifestation of the inhibitory jaw reflex evoked by stimulation of the human upper lip, can be modulated by experimentally-controlled conditions that mimic symptoms of a myogenous temporomandibular disorder. Methods: Three series of experiments were performed on 49 volunteer subjects in total. The experiments involved recording bite forces between the anterior teeth and electromyograms (EMGs) from the masseter muscles. Transcutaneous electrical stimuli were applied to the hairy skin of upper lip while the subjects maintained a biting force of around 50N with the aid of visual feedback. In the first series of experiments, a range of electrical stimuli below and above the nociceptive threshold was delivered. In the second set of experiments, double stimuli with a range of different inter-stimulus intervals were applied. Finally in a third series of experiments, electrical stimulation was repeated before, immediately after, and 5 and 10 minutes following a 3-minute accelerated chewing task. This task consisted of chewing 1.5g of a tough chewing gum at 1.5 times the subject’s natural chewing rate and in 18 cases, muscle fatigue and/or pain were reported by the subjects. Results: Following stimulation at intensities that were described as sharp or painful, all the subjects showed both a suppression of the masseter EMG and a reduction of biting force. When analysing the maximum responses in each subject, the mean reduction in the EMG inhibition was to 15.78 ± 14.4% and 10.39 ± 7.92% of the baseline (for the ipsi- and contra-lateral EMGs respectively), whereas the biting force was reduced only to 83.98 ± 11.04% of baseline (+ S.D.). The latencies of onset of these responses were: 38.17 ± 3.58ms, 38.97 ± 4.49ms and 51.83 ± 6.23ms respectively. The response observed in the force record was weaker than in that observed in either EMG (Paired t tests, P < 0.005 in both cases). When applying double stimuli, it was found that the prolongation of the EMG inhibitory jaw reflex (to 144.70 ± 46.93% of the control level) evoked by double stimulation of the upper lip (with a 10 ms inter-stimulus interval) resulted in a greater increase in the depth of the accompanied relaxation (to 223.63 ± 70.88% of that seen in the control responses) compared to a relatively smaller increase in the duration of the relaxation (to 128.32 ± 27.23% of that seen in the control responses). Following the accelerated chewing task, 17 out of 22 subjects reported pain and/or fatigue in one or both of the masseter muscles. The integral for the bite force relaxation significantly decreased in size immediately following the conditioning procedure (to 76.04 ± 35.63% of the control level, P = 0.014; single sample t-test with Bonferroni correction, test value 100). Conclusion: The inhibitory jaw reflex evoked by stimulation of the human lip can be demonstrated mechanically as well as electromyographically although the mechanical version of the response appears less marked. In addition to that, the onset of reflex relaxation in bite force lags several milliseconds behind the corresponding reductions in electromyographic activity. The depth of force relaxation can be increased by increasing the duration of EMG recorded inhibitory reflex. Finally, the results from a chewing task suggest that induced acute pain and/or fatigue cause clear changes in the mechanical manifestation of this inhibitory jaw reflex.
105

Análise eletromiográfica e de força de mordida de pacientes acometidos por desordens temporomandibulares submetidos ao tratamento com placa oclusal / Electromyographic and bite force analysis of patients suffering from temporomandibular disorders undergoing treatment with occlusal splints

Gentil, Flávio Henrique Umeda 17 January 2012 (has links)
O diagnóstico das desordens temporomandibulares toma como base as informações colhidas sobre a sintomatologia durante a anamnese, o exame clínico da oclusão e os exames radiológicos das articulações temporomandibulares. Na busca de melhor compreensão da fisiopatologia que afeta a musculatura do sistema estomatognático, a análise eletromiográfica tem sido incluída em muitos estudos, pois permite a identificação de quando e como um músculo é ativado e, ainda, a determinação de como se estabelece a coordenação dos músculos envolvidos no movimento. Outros estudos têm demonstrado ainda a utilidade de se mensurar a força de mordida de sujeitos com desordens temporomandibulares, como um método adicional para se compreender a função dos músculos mastigatórios dos mesmos. O objetivo geral desse trabalho foi analisar e comparar a atividade de pares de músculos por meio de eletromiografia, durante provas de apertamento dental e de mastigação, além de analisar o desempenho dos músculos mastigatórios pela mensuração da força de mordida, antes e após o tratamento com placa oclusal, realizando ainda para ambos uma análise de confiabilidade dos testes (repetibilidade). A amostra foi composta por 15 sujeitos com desordem temporomandibular e 20 sujeitos controle, sem sinais ou sintomas de desordens temporomandibulares, segundo a classificação proposta pelo protocolo do Research Diagnostic Criteria for Temporomandibular Disorders. Os exames eletromiográficos e de força de mordida foram realizados no Laboratório de Pesquisa em Eletromiografia do Sistema Estomatognático. Foram encontradas diferenças estatísticas no índice POCmm, entre os grupos DTMi e DTMf, para o teste estático; no índices ciclo e frequência, ambos do lado esquerdo, entre os grupos DTMi e DTMf, para o teste dinâmico; e entre os grupos Controle e DTMi para os testes de força de mordida. Além disso, foi encontrada uma concordância estatisticamente significativa entre os dados de força de mordida, POC Médio e tors. Obteve-se com este estudo a melhor compreensão do diagnóstico das DTMs por meio da análise instrumental, conferindo um sentido biológico à eletromiografia de superfície e à avaliação da força de mordida, nos casos de desordens temporomandibulares. / The diagnosis of temporomandibular disorders is based on the information collected about symptoms during clinical examination of the occlusion and radiological examinations of the temporomandibular joints. In the search for better understanding of the pathophysiology that affects the muscles of the stomatognathic system, electromyographic analysis has been included in many studies because allows the identification of when and how a muscle is activated and also the determination of how the coordination of muscles is involved in movement. Other studies have also demonstrated the usefulness of measuring bite force of subjects with temporomandibular disorders, as an additional method for understanding the function of the masticatory muscles of the same. The aim of this study was to analyze and compare the activity of pairs of muscles by electromyography during clenching and chewing tests, and analyze the performance of masticatory muscles by measuring the bite force before and after treatment with occlusal splints, and still performing, for both, a reliability analysis of the tests (repeatability). The sample consisted of 15 subjects with temporomandibular disorder and 20 control subjects without signs or symptoms of temporomandibular disorders according to the classification proposed by the protocol of the Research Diagnostic Criteria for Temporomandibular Disorders. The electromyographic examinations and bite force were performed at the Laboratory of Research in Electromyography of the Stomatognathic System. Significant differences were found in the index POCmm among the groups DTMi and DTMf, for the static test; for the index cycle and frequency, both on the left side, among groups DTMi and DTMf for the dynamic test; and among the control and DTMi groups for the bite force test. In addition, we found a statistically significant correlation between the bite force data, POC Médio and tors. In the end, this study provided a better understand of the diagnosis of TMD by instrumental analysis, providing a biological sense to the surface electromyography and to the evaluation of bite force in cases of temporomandibular disorders.
106

Estudo comparativo entre as grades palatinas removível e fixa, associadas à mentoneira, no tratamento da mordida aberta anterior / Comparative study between removable and fixed cribs, associated to chincup, in anterior open bite treatment

Torres, Fernando César 22 September 2008 (has links)
Este estudo teve como objetivo avaliar comparativamente as alterações dentoalveolares e do perfil tegumentar, decorrentes do tratamento da mordida aberta anterior com grade palatina removível (Grupo 1) e com grade palatina fixa (Grupo 2), ambas associadas à mentoneira. O Grupo 1 apresentou idade inicial média de 8,33 anos e overbite inicial de -4,07mm, enquanto o Grupo 2 apresentou idade inicial de 8,54 e overbite de -4,33. Cada grupo foi composto de 30 pacientes, em fase de dentadura mista, com mordida aberta anterior de pelo menos 1mm, incisivos permanentes erupcionados e relação molar de Classe I. O período de avaliação foi de 12 meses, entre a tomada da primeira (T1) e da segunda (T2) telerradiografia lateral. A recomendação de uso da grade palatina removível foi de período integral (exceto durante as refeições e higiene bucal). O tempo de utilização da mentoneira foi de aproximadamente 12h/dia, com uma força de 450 a 500g por lado, direcionada 45º acima do plano oclusal. A comparação das características cefalométricas iniciais evidenciou similaridade entre os grupos, sendo que os fatores idade, gênero e tempo de observação também foram semelhantes. Os resultados não mostraram diferença significante na erupção ou na mesialização dos molares. As modificações dentoalveolares na região anterior foram evidentes, havendo maior extrusão dos incisivos superiores no grupo com grade fixa, proporcionando um maior aumento do overbite nesse grupo. A grade fixa provocou uma menor inclinação para palatino dos incisivos superiores, porém levou a uma maior inclinação para lingual dos incisivos inferiores, em relação à grade removível, o que causou um maior aumento do overjet. Algumas variáveis relacionadas ao perfil mole apresentaram diferenças estatisticamente significantes: o Grupo 2 apresentou maior aumento no comprimento do lábio superior, maior fechamento do espaço interlabial e, sem significância estatística, retrusão dos lábios superior e inferior. Pode-se concluir que a grade fixa corrigiu de forma mais eficiente a mordida aberta anterior, porém provocou um maior aumento do overjet. / The objective of this prospective clinical study was to cephalometrically compare the dentoalveolar and soft tissue effects produced by two kinds of anterior open bite treatments: removable palatal crib (Group 1) and fixed palatal crib (Group 2), both associated to the use of chincup. Group 1 presented initial mean age of 8.33 years and mean anterior open bite of 4.07mm. Group 2 presented initial mean age of 8.54 years and mean anterior open bite of 4,33mm. Each group comprised 30 patients, in mixed dentition phase, with similar cephalometric characteristics and skeletal ages. The evaluation period comprised 12 months between initial (T1) and second lateral radiograph (T2). Results showed no statistically significant differences in molar eruption or mesialization, showing that vertical changes at the posterior region were similar between the groups. Dentoalveolar changes at the anterior region were evident, with statistically significant more extrusion of maxillary incisors in the group of fixed crib, what contributed to a more accentuated overbite increase in this group. Patients treated with fixed crib also presented less lingual tipping of maxillary incisors and more lingual tipping of mandibular incisors. Some variables related to the soft profile presented statistically significant changes between the groups: Group 2 presented a greater increase in upper lip length, more closure of the interlabial gap and, with no statistical significance, more retrusion of lower and upper lip. So, patients that utilized the fixed palatal crib had a more efficient correction of the anterior open bite; however, they had more increase of the overjet.
107

Estabilidade do tratamento precoce da mordida aberta anterior, utilizando aparelho removível com grade palatina, associado à mentoneira / Stability evaluation of early open bite treatment using a removable appliance with palatal crib combined with high-pull chincup

Ferreira, Fernando Pedrin Carvalho 17 October 2008 (has links)
O objetivo desta pesquisa foi avaliar cefalometricamente a estabilidade das alterações dentoesqueléticas e tegumentares, no protocolo de tratamento com o aparelho removível com grade palatina associado à mentoneira, em jovens portadores de mordida aberta anterior, tratados por 12 meses e comparar com um Grupo de jovens portadores de má oclusão semelhante que não foram submetidos ao tratamento ortodôntico. Avaliou-se um total de 76 telerradiografias em norma lateral de 38 jovens. Dois Grupos compuseram a amostra: o Grupo 1 (controle) composto por 19 jovens (idade média de 9,10 anos) que não receberam qualquer tratamento para a correção de sua má oclusão e o Grupo 2 (tratado) composto por 19 jovens (idade média de 9,78 anos) que receberam o protocolo de tratamento durante 12 meses. Verificou-se a estabilidade do tratamento da má oclusão durante aproximadamente 15 meses após a remoção dos aparelhos. Os dados obtidos nas medidas cefalométricas (diferenças das médias das alterações) para os dois Grupos foram computados pelo teste t de Student não pareado. Os resultados mostraram que os componentes esquelético e tegumentar não apresentaram alterações significantes. O overbite, overjet e posicionamento dos dentes superiores mantiveram-se estáveis. Os incisivos inferiores vestibularizaram e protruíram no Grupo tratado enquanto o Grupo controle apresentou maior extrusão destes dentes. Os molares inferiores também extruíram mais significantemente no Grupo controle. Pode-se concluir que o protocolo de tratamento da mordida aberta anterior utilizando aparelho removível com grade palatina associado à mentoneira mostrou estabilidade de aproximadamente 95%, ressaltando a grande importância deste tratamento em idade precoce. / The aim of this study was to cephalometrically investigate the stability of early open bite treatment. Nineteen children with a mean age of 9.78 years old that were treated for 12 months with a removable appliance with palatal crib associated with chincup were evaluated after 15 months (posttreatment period) and compared with a control group of 19 subjects with mean age of 9.10 years with the same malocclusion that was followed-up for the same period. The 76 lateral cephalograms were evaluated at T1 (after correction) and T2 (follow-up) and cephalometric variables were analyzed with statistical tests. The results did not show significant skeletal, soft tissues or maxillary dentoalveloar changes. Overall, treatment effects in the experimental group were maintained at T2 evaluation with an increase of 0.56mm in overbite. Overjet and maxillary incisors/molars position (vertical and sagittal) remained essentially unchanged during the study period. Only mandibular incisors showed some significant changes (labial inclination and protrusion) compared with the controls. Thus, it can be conclude that the early open bite treatment with a removable appliance and palatal crib associated with high-pull chincup therapy provided stability of 95%.
108

Impacto do exercício aeróbico intenso (corrida) na musculatura do sistema estomatognático - análise eletromiográfica, espessura muscular, força de mordida e eficiência mastigatória / Impact of intense exercise aerobic (running) in muscle stomatognathic system - electromyographic evaluation, muscle thickness, bite force and masticatory efficiency

Amoras, Dinah Ribeiro 09 May 2014 (has links)
A corrida de rua é descrita como uma atividade aeróbica intensa que atualmente envolve milhões de adeptos. A prática regular desta modalidade esportiva promove alterações nos músculos estriados esqueléticos fato que despertou o interesse em analisar, por meio da eletromiográfica (EMG - Myosystem), seu efeito sobre a atividade dos músculos do sistema estomatognático masseter e temporal em diferentes posições posturais da mandíbula, além de sua espessura por meio da ultrassonografia (Ultrassom portátil SonoSite Titan Nacionalizado), como também, a força de mordida máxima utilizando o dinamômetro digital modelo IDDK- Kratos posicionado na região dos primeiros molares. Foram avaliados 40 indivíduos adultos com idades entre 18 a 65 anos, de ambos os gêneros sem alterações clínicas do sistema estomatognático divididos em dois grupos: Grupo I Corredores e Grupo II Controle, pareados sujeito a sujeito. As médias eletromiográficas foram tabuladas e submetidas à análise estatística utilizando Teste t (SPSS 19.0). Os resultados evidenciaram diferenças significantes (p<0,05) para atividades eletromiográficas no grupo formado por indivíduos praticantes da corrida de rua ocorrendo um maior equilíbrio muscular funcional nas posturas clínicas analisadas. Nas condições em que este estudo foi desenvolvido os resultados indicam que a corrida de rua promoveu alterações significativas no sistema mastigatório. / Running is described as an intense aerobic activity which currently involves millions of fans. Regular practice of this sport promotes changes in skeletal muscles striated fact which aroused interest in analyzing through the electromyographic ( EMG - Myosystem ) , its effect on the activity of the muscles of the stomatognathic system masseter and temporalis muscles in different positions mandible posture , plus its thickness by ultrasonography (SonoSite Titan portable Ultrasound Nationalized ) , as well as the maximum bite force using a digital dynamometer model IDDK Kratos - positioned in the region of the first molars . We evaluated 40 adults aged 18-65 years, of both genders without clinical alterations of the stomatognathic system divided into two groups: Group I Runners and Group II Control matched each subject. The average EMG were tabulated and subjected to statistical analysis using t Test (SPSS 19.0). The results showed significant differences (p < 0.05) in EMG activity for group of individuals practicing the street race occurring more functional muscle balance postures analyzed clinical. In the conditions in which this study was conducted the results indicate that the road race promoted significant changes in the masticatory system.
109

Evolution of the Hammerhead Cephalofoil: Shape Change, Space Utilization, and Feeding Biomechanics in Hammerhead Sharks (Sphyrnidae)

Mara, Kyle Reid 31 August 2010 (has links)
The relationship between form and function is often used to elucidate the biological role of a structure. Hammerhead sharks offer a unique opportunity to study form and function through phylogeny. Because sphyrnid sharks display a range of cranial morphologies this group can be used to address questions about the evolution of cranial design and investigate the effects of changes in head morphology on feeding structures and bite force. Geometric morphometrics, volumetric analyses, morphological dissections, and phylogenetic analyses of the cephalofoil were used to gain insight into changes in cranial design through evolutionary history. External morphometrics and internal volumetric analyses indicated that while the external shape of the cephalofoil and placement of the sensory structures is variable through evolutionary history, the volumes of the internal cranial elements do not change. Constructional constraints within the cephalofoil were confined to sensory structures while feeding morphology remained relatively unchanged. Analysis of the morphology and biomechanics of the feeding apparatus revealed that through phylogeny the feeding system does not change among sphyrnid species. However, size-removed bite force was lower than predicted for all sphyrnid species except Sphyrna mokarran. Despite differences in head morphology between sphyrnid and carcharhinid sharks, the feeding bauplan is conserved in sphyrnid sharks with few changes to the feeding structures. Instead the chondrocranial and sensory structures are modified around the relatively static feeding core. Finally, the durophagous S. tiburo was found to consume hard prey in a manner that is biomechanically and morphologically different from other durophagous fishes. Furthermore, the diet of S. tiburo is constrained by the properties of its preferred prey.
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The effects of scaling on bite force and suction index in the eastern hellbender (Cryptobranchus alleganiensis)

Larghi, Nicholas Patrick 01 January 2013 (has links)
The hellbender (Cryptobranchus alleganiensis) is a salamander that grows over a large range of body sizes (2-74 cm total length) making it an ideal organism for examining the effects of body size on morphology and performance. The goal of this study is to investigate the morphology changes over ontogeny and change in feeding ability. Cryptobranchus feeds on small aquatic insects as juveniles and shifts to crayfish as they get larger. Morphology can be expected to change as an organism grows larger, and because morphology and performance are closely linked, this morphological change can result in a change in feeding ability. Cryptobranchus alleganiensis are primarily aquatic salamanders that utilize both suction feeding and biting behaviors. I hypothesize bite force would increase with positive allometry reflecting a possible dietary shift during ontogeny in which larger Cryptobranchus favor crayfish. Because suction is the primary mode of feeding making it an important aspect of feeding throughout ontogeny, suction index was hypothesized to scale with isometry. Fourteen preserved specimens (11.9-34.5 cm SVL) were used to investigate the effects of scaling on suction potential and estimated bite force. Bite force was calculated using a 3D static equilibrium model and suction potential was calculated as suction index. Bite force scaled with positive allometry allowing the animals to bite harder relative to body mass with increasing body size, and suction index showed no effect of body size. Results of this study indicate that Cryptobranchus alleganiensis maintains suction performance across ontogeny allowing them to generate suction with similar ability ontogenetically, but increases its biting performance to cope with durophagous prey with a possible ontogenetic dietary shift.

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