O objetivo deste estudo foi analisar os ruídos das articulações temporomandibulares (ATM) e a atividade eletromiográfica (EMG) dos músculos masseteres (MM) e temporais anteriores (TA) nos momentos pré e pós correção da mordida cruzada posterior funcional (MCPF) por meio da expansão rápida da maxila (ERM) com o uso do aparelho ortopédico Haas modificado. A amostra foi composta por 20 crianças (entre 6 e 12 anos de idade, de ambos gêneros) portadoras de MCPF. A eletrovibratografia (EVG) avaliou a presença de ruídos articulares. A eletromiografia (EMG) foi analisada nas situações clínicas de máxima contração voluntária em máxima intercuspidação habitual e mastigação habitual, direita e esquerda nos momentos pré tratamento (T1) e após três meses da finalização da ERM (T2). Os resultados mostraram que: não houve diferença estatística nos ruídos articulares entre o lado afetado e não afetado pela MCPF nos momentos T1 e T2, houve uma melhora do ruído articular com diminuição no pico de amplitude da vibração do lado da MCPF na comparação dos lados não afetados pela MCPF. No teste da EMG a avaliação em repouso e no teste funcional não mostrou diferenças estatisticamente significantes entre lado afetado e não afetado pela MCPF. Houve diferença estatística nas mastigações direita e esquerda tanto para MM como para os TA na mastigação do lado da MCPF sendo que atividade EMG aumentou para estes músculos no T1 do lado não afetado. Na comparação entre o lado afetado e não afetado, os MM e os TA aumentaram sua atividade EMG no T1 na mastigação do lado da MCPF e somente o MM apresentou aumento da atividade EMG na mastigação do lado não afetado pela MCPF. Na comparação entre os lados de MCPF no T1 com T2 e na comparação entre os lados não afetados pela MCPF na avaliação da mastigação de ambos os lados o MM apresentou aumento da atividade EMG nos momentos T1 e T2, com diferenças estatísticas significantes. Em conclusão, o tratamento precoce da ERM diminui a intensidade dos ruídos articulares do lado afetado pela MCPF e gera um equilíbrio nas funções mastigatórias após tratamento ortopédico da MCPF. Estes achados indicam que o tratamento precoce da MCPF favorece a obtenção de condições morfológicas e funcionais adequadas para um melhor desenvolvimento do sistema estomatognático. / The objective of this study was to analyze the temporomandibular joint (TMJ) noise and the electromyographic (EMG) activity of the masseter (MM) and anterior temporal (TA) muscles at the moments before and after correction of functional posterior crossbite (MCPF) by rapid expansion of the maxilla (ERM) with the use of the modified Haas orthopedic device. The sample consisted of 20 children (between 6 and 12 years of age, of both genders) with MCPF. Electrovibratography (EVG) evaluated the presence of joint noises. Electromyography (EMG) was analyzed in the clinical situations of maximum voluntary contraction in maximal habitual intercuspation and habitual chewing, right and left at the pre-treatment (T1) moments and after three months of the completion of ERM (T2). The results showed that: there was no statistical difference in articular noise between the affected and unaffected side of the MCPF at moments T1 and T2, there was an improvement in articular noise with a decrease in the peak of vibration amplitude on the MCPF side in the comparison of the non- affected side of the MCPF. In the EMG test, the evaluation at rest and in the functional test did not show statistically significant differences between the affected and non-affected side of the MCPF. There was a statistically significant difference in right and left chewing for both MM and TA in chewing on the MCPF side and EMG activity increased for these muscles in T1 on the unaffected side. In the comparison between the affected and unaffected side, MM and TA increased their EMG activity in T1 in chewing on the MCPF side and only MM showed increased EMG activity in chewing on the side not affected by MCPF. In the comparison between the MCPF sides in T1 with T2 and in the comparison between the sides not affected by MCPF in the chewing evaluation of both sides, the MM showed an increase in EMG activity at moments T1 and T2, with significant statistical differences. In conclusion, early treatment of MRE reduces the intensity of articular noises on the MCPF affected side and generates a balance in masticatory functions after orthopedic treatment of MCPF. These findings indicate that the early treatment of MCPF favors the achievement of morphological and functional conditions adequate for a better development of the stomatognathic system.

Orientador: Ana Carolina Pero Vizoto / Resumo: O período de adaptação funcional com as próteses totais novas envolve uma série de problemas transitórios, e este período está diretamente relacionado com o sucesso ou falha do tratamento. O objetivo deste estudo foi avaliar a influência da altura do rebordo mandibular no padrão de movimentos mandibulares, na máxima força de mordida oclusal, na função mastigatória, na ingestão de nutrientes e na satisfação dos pacientes em diferentes estágios após a instalação de próteses totais convencionais novas. Vinte e oito indivíduos desdentados totais (RN, n=14, rebordos mandibulares normais; RR, n=14, rebordos mandibulares reabsorvidos) receberam novas próteses totais convencionais. Um cinesiógrafo foi utilizado para registrar os movimentos mandibulares durante a abertura e fechamento e a mastigação de um alimento teste. A máxima força oclusal foi mensurada com o auxílio de um gnatodinamômetro digital, o desempenho mastigatório foi avaliado por meio do método dos tamises e a habilidade mastigatória pela aplicação de questionário específico baseado em uma escala visual analógica (EVA de 100,0 mm), a satisfação foi avaliada por meio de um questionário. A ingestão de nutrientes foi avaliada por meio de diário alimentar de três dias, e posteriormente foi traduzido em valores nutricionais por meio da utilização da Tabela Brasileira de Composição de Alimentos. Essas avaliações foram conduzidas em momentos distintos: 24 horas, 30 dias, três meses e seis meses após a instalação das próteses t... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Les mouvements masticatoires sont générés par un réseau neuronal localisé dans le tronc cérébral connu sous le nom de générateur de patron central (GPC). De plus en plus d’évidences dans la littérature associent le noyau sensoriel principal du trijumeau (NVsnpr) au cœur rythmogène du GPC masticatoire, bien qu’il soit traditionnellement considéré comme un relais sensoriel au thalamus. La présente étude amène une nouvelle preuve de connectivité fonctionnelle entre le NVsnpr et le noyau moteur du trijumeau (NVmt) contenant les motoneurones (MNs) innervant les différents muscles masticatoires. Nos résultats indiquent que les neurones projetant vers NVmt sont situés dans le ¾ dorsal du NVsnpr. La stimulation électrique dans le NVsnpr dorsal évoque des réponses synaptiques excitatrices multiphasiques dans les MNs trigéminaux tandis que l'application locale de BAPTA, connue pour induire une activité rythmique dans les neurones du NVsnpr, évoqua aussi une activité rythmique dans les MNs, supportant davantage la relation fonctionnelle entre ces deux noyaux en termes de transmission de rythme. En imagerie calcique, la stimulation électrique de NVsnpr évoquait des réponses calciques dans les MNs situées principalement dans la région dorsolatérale contenant les MNs des muscles de fermeture et révéla un patron spécifique de connectivité entre les deux noyaux. L'organisation des projections semblait dépendre de manière critique de la localisation dorso-ventrale du site de stimulation au sein du NVsnpr. La principale tendance observée concernait la région DL de NVmt recevant des inputs du NVsnpr dorsal (R1 et R2), alors que la région ventromédiane de NVmt recevait plutôt des inputs de R2 et R3, qui représentent la majeure partie de la région intermédiaire du NVsnpr. Cette étude confirme et développe les expériences antérieures en explorant la nature physiologique et la topographie fonctionnelle de la connectivité entre NVsnpr et NVmt. / Masticatory movements are generated by a brainstem neuronal network known as the central pattern generator (CPG). Increasing evidence associate the trigeminal main sensory nucleus (NVsnpr) to the rhythmogenic heart of the masticatory CPG, despite the fact that it is conventionally seen as a sensory relay to the thalamus. The present study provides new evidence of a functional connectivity between NVsnpr and the trigeminal motor nucleus (NVmt), known to contain all the motoneurons (MNs) innervating jaw muscles. Our results indicate that neurons projecting to NVmt are located in the dorsal ¾ region of NVsnpr. Electrical stimulation of the dorsal NVsnpr induced multiphasic excitatory synaptic responses in trigeminal MNs while BAPTA application, which causes NVsnpr neurons to fire rhythmically, also induced rhythmic firing in some MNs, further emphasizing the functional relationship between these two nuclei in terms of rhythm transmission. In our calcium imaging experiments, electrical stimulation of NVsnpr evoked calcium responses in MNs located mainly in the jaw-closing region of NVmt and revealed a specific pattern of connectivity between the two nuclei. The organization of the projections seemed to depend critically on the dorsoventral location of the stimulation site within NVsnpr. The dorsolateral region of NVmt received mainly inputs from the dorsal NVsnpr (R1 and R2), whereas the ventromedial region of NVmt was found to receive inputs from R2 and R3 which account for the major part of the intermediate division of the NVsnpr. This study confirms and develops earlier experiments by exploring the physiological nature and functional topography of the connectivity between NVsnpr and NVmt that was demonstrated in the past with neuroanatomical techniques.

Land managers need to rapidly assess vegetation composition and bare ground to effectively evaluate, manage, and restore shrub steppe communities that have been encroached by pinyon and juniper (P-J) trees. A major part of this process is assessing where to apply mechanical and prescribed fire treatments to reduce fuel loads and maintain or restore sagebrush steppe rangelands. Geospatial technologies, particularly remote sensing, offers an efficient option to assess rangelands across multiple spatial scales while reducing the need for ground-based sampling measurements. High-spatial resolution color-infrared imagery (0.06-m pixels) was acquired for sagebrush steppe communities invaded by P-J trees at five sites in Oregon, California, Nevada, and Utah with a Vexcel Ultra CamX digital camera in June/July 2009. In addition to untreated P-J woodlands, imagery was acquired over P-J woodlands where fuels were reduced by either prescribed fire, tree cutting, or mastication treatments. Ground measurements were simultaneously collected at each site in 2009 on 0.1-hectare subplots as part of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP). We used Trimble eCognition Developer to 1) develop efficient methods to estimate land cover classes found in P-J woodlands; 2) determine the relationship between ground measurements and object-based image analysis (OBIA) land cover measurements for the following classes: trees (live, burned, cut, and masticated), shrubs, perennial herbaceous vegetation, litter (including annual species), and bare ground; and 3) evaluate eCognition rule-sets (models) across four spatial scales (subplot, site, region, and network) using untreated P-J woodland imagery. At the site scale, the overall accuracy of our thematic maps for untreated P-J woodlands was 84% with a kappa statistic of 0.80. For treatments, the overall accuracy and kappa statistic for prescribed fire was 85% and 0.81; cut and fell 82% and 0.77, and mastication 84% and 0.80, respectively, each indicating strong agreement between OBIA classification and ground measured data. Differences between mean cover estimates using OBIA and ground-measurements were not consistently higher or lower for any land cover class and when evaluated for individual sites, were within 5% of each other; all regional and network OBIA mean cover estimates were within 10% of the ground measurements. The trade-off for decreased precision over a larger area (region and network scale) may be useful to prioritize fuel-management strategies but will unlikely capture subtle shifts in understory plant communities that site and subplot spatial scales often capture. Although cover assessments from OBIA differed somewhat from ground measurements, they were accurate enough for many landscape-assessment applications such as evaluating treatment success and assessing the spatial distribution of fuels following fuel-reduction treatments on a site scale.

La mastication est une fonction essentielle relevant de la coordination d’un ensemble d’acteurs que sont la mâchoire, la langue et les muscles faciaux. La synchronisation de l’activité des différentes parties relève d’un réseau spécialisé de neurones nommé générateur de patron central (GPC) dont il a été proposé que le coeur rythmogène soit formé des neurones de la partie dorsale du noyau sensoriel principal du trijumeau (NVsnpr). Ces neurones ont la capacité intrinsèque de pouvoir alterner leur patron de décharge entre un mode tonique et rythmique en fonction la concentration extracellulaire de calcium ([Ca2+]e). Autrefois relégués à un rôle passif dans le système nerveux central, les évidences se sont accumulées en faveur d’un rôle actif des astrocytes dans les fonctions physiologiques. À cet effet, dans le NVsnpr, la stimulation des afférences sensorielles trigéminales active les astrocytes qui participent à la genèse du rythme masticateur en libérant la S100β, une protéine chélatrice du Ca2+ extracellulaire. Récemment, il a été démontré que l’activation rythmique des neurones du NVsnpr dorsal menait à une activation rythmique des motoneurones (MNs) innervant les muscles masticateurs. Ceci impliquerait qu’une seule population de neurone au sein du NVsnpr dorsal active de manière concomitante des MNs innervant les muscles antagonistes de la mâchoire. On suppose alors l’activation de la région péritrigéminale (PeriV), un réseau d’interneurones prémoteurs (INs) ceinturant les MNs du trijumeau et adjacente au NVsnpr. Son activation modulerait l’activité des MNs de muscles antagonistes. Les présents travaux réalisés en imagerie calcique indiquent que l’activation du NVsnpr par une baisse de la [Ca2+]e, simulant l’action de la S100β ou la stimulation électrique des afférences sensorielles trigéminales activent les neurones et astrocytes de la partie dorsale du NVsnpr et subséquemment les INs de la PeriV. Les patrons d’activité calcique des INs de la PeriV étaient similaires à ceux observés au sein du NVsnpr. Ces observations supportent par la même occasion la transmission des patrons en provenance du NVsnpr, le générateur du rythme masticateur vers la région prémotrice PeriV. Par ailleurs, les astrocytes péritrigéminaux dont le rôle n’avait jamais été investigué ont également répondu aux activations du NVsnpr dans des patrons d’activité calcique similaires aux astrocytes du NVsnpr dorsal. Ensemble, ces résultats suggèrent l’implication de la région PeriV dans la transmission et la modulation du rythme dans le GPC masticateur. / Mastication is an essential function that involves coordination of the jaw, tongue and facial muscles. Synchronization of the activity of these different parts is assured by a specialized network of neurons known as central pattern generator (CPG), whose rhythmogenic core has been proposed to be formed by neurons in the dorsal part of the trigeminal principal sensory nucleus (NVsnpr). These neurons have the intrinsic ability to alternate their firing pattern between a tonic and rhythmic mode, depending on the extracellular calcium concentration ([Ca2+]e). Once relegated to a passive role in the central nervous system, evidence is accumulating in favor of an active role for astrocytes in physiological functions. In NVsnpr, trigeminal sensory afferents stimulation activates astrocytes, which participate in the genesis of the masticatory rhythm by releasing S100β a calcium-binding protein that lowers [Ca2+]e. Recently, it has been demonstrated that rhythmic activation of dorsal NVsnpr neurons leads to rhythmic activation of motoneurons (MNs) innervating masticatory muscles. This would imply that a single neuron population within the dorsal NVsnpr concomitantly activates MNs innervating antagonistic jaw muscles. We presume that activation of the peritrigeminal region (PeriV), a network of premotor interneurons (INs) surrounding the trigeminal MNs and adjacent to the NVsnpr could modulate the activity of antagonistic muscle MNs. The present calcium imaging work indicates that activation of the NVsnpr by a decrease in [Ca2+]e, simulating the action of S100β, or electrical stimulation of trigeminal sensory afferents activates neurons and astrocytes in the dorsal part of NVsnpr and subsequently the INs of the PeriV. Calcium activity patterns in PeriV INs were similar to those observed in NVsnpr, supporting the transmission of patterns from NVsnpr, the generator of masticatory rhythm, to the PeriV premotor region. In addition, previously uninvestigated peritrigeminal astrocytes also responded to NVsnpr activations with calcium activity patterns similar to those of dorsal NVsnpr astrocytes. Taken together, these results suggest the involvement of the PeriV region in rhythm transmission and modulation in the masticatory CPG.

La compréhension et la modélisation des phénomènes régissant la libération des stimuli orosensoriels durant la consommation d'un aliment doit permettre de respecter des critères de conception à la fois nutritionnels et organoleptiques. Un modèle de libération du sel au cours de la mastication a été développé pour des produits " solides ". La déstructuration du produit a été appréhendée en terme de génération de surface de contact entre le produit et la salive qui gouverne les transferts de sel. La surface de contact a été considérée comme étant le produit de deux fonctions. La première est reliée au sujet et est fonction de son efficacité masticatoire. La seconde est reliée au produit et dépend de ses propriétés de déstructuration qui peuvent être déterminées par des tests in vitro. Durant la phase pharyngée, la biomécanique de la déglutition gouverne l'enduction des muqueuses par le bol alimentaire et ainsi la libération des composés d'arôme présents dans cette couche. Ces phénomènes sont régis par un écoulement en film mince, stationnaire, dans un contact élastohydrodynamique mou dont la cinématique équivaut à un processus d'enduction par des cylindres contrarotatifs lubrifiés par de la salive. Deux régimes ont été distingués. Lorsque le film de salive est fin, la viscosité du bol alimentaire a un grand rôle sur l'enduction et la libération des composés d'arôme. Lorsque le film de salive est épais, le bol est dilué par la salive durant le processus de déglutition et sa viscosité a un faible effet sur l'enduction et la libération des composés d'arôme. Ce second régime permet d'expliquer l'origine physique d'observations in vivo concernant la libération des composés d'arôme.

La littérature scientifique révèle que les résultats in vitro sur les matériaux dentaires ont une faible corrélation avec le comportement clinique. Les tests standardisés aux normes fournissent des informations précieuses et pertinentes sur les propriétés des matériaux dentaires, et permettent aussi de comparer les résultats de différents instituts. Cependant, le développement de nouveaux matériaux à partir de nouvelles formulations chimiques nécessite une amélioration des méthodes d'évaluation. Ce travail de recherche est réalisé dans le but d'approfondir les connaissances sur les méthodes d'évaluation des matériaux dentaires avant insertion dans la cavité buccale. Une grande importance a été donnée au choix des matériaux à tester ; nous nous sommes basés sur les dernières tendances actuelles et les derniers développements de composition de matériaux dentaires. La même importance a été donnée à des méthodes et des techniques d'essai au laboratoire ; leur corrélation avec les résultats cliniques a été mise en évidence. Les modifications apportées à la méthodologie de ces tests ont exploré davantage les aspects cachés des différentes interactions de paramètres. La caractérisation et l'évaluation des matériaux dentaires nécessitaient une meilleure compréhension de l'interaction entre les différentes propriétés pour expliquer le vieillissement des matériaux. Notre travail a consisté à combiner de nombreuses études pour répondre à ce sujet. Les études ont porté sur les propriétés mécaniques et physiques, le composite fibré et Bulk, les matériaux CAM CAD, les adhésifs dentaires, le choc thermique et le cyclage thermique, le bisphénol A. L'objectif final était de développer un simulateur oral qui permettrait la reproduction de différents paramètres chimiques, physiques et mécaniques de l'environnement buccal, permettant ainsi de combler l'écart entre les tests in vitro et in vivo de matériaux dentaires / Scientific literature reveals that in vitro results are poorly correlated to materials clinical behavior. ISO standardized testing provides valuable information about the dental materials properties, and enables result comparison between different institutes. Conversely, new materials chemistry and formulations requires improved methodology and testing methods. Throughout our studies included in this work, the main objective was to reach a more global knowledge of the way dental materials are evaluated before being inserted into the oral cavity. A great deal of emphasis was given to the choice of materials to be tested, and that it would represent the current trends in dental practice and the latest developments in material composition. Equal highlight was given to the choice of testing methodology and laboratory testing techniques and their correlation to the clinical outcome. The modifications made to the methodology of these tests explored further the concealed aspects of different parameter interactions. Dental materials characterization and assessment required more understanding about the interaction between different properties to explain material aging; our work was to combine numerous studies to answer this topic. The studies included mechanical and physical properties, bulk and fiber composite, CAD CAM block materials, dental resin adhesive, thermal shock and thermal cycling, Bisphenol A. The final objective was to develop an oral simulator that would enable the reproduction of different chemical, physical and mechanical parameters of the oral environment, thus permitting to bridge the gap between in vitro and in vivo testing of dental materials

No description available.

De nombreuses fonctions cérébrales dépendent de la capacité de réseaux de neurones à générer une activité rythmique. Les réseaux neuronaux, nommés générateurs de patron centraux (GPCs), contrôlant les patrons de mouvements répétitifs comme la locomotion, la respiration et la mastication en sont un exemple important. Des travaux antérieurs ont montré que le noyau sensoriel principal du trijumeau (NVsnpr), qui fait partie du GPC de la mastication, contient des neurones qui peuvent décharger de façon rythmique et que les astrocytes et leur protéine S100ß étaient nécessaires pour cette rythmogénèse neuronale. Cependant, l’effet de l’activation directe des astrocytes sur la décharge des neurones du NVsnpr n’a jamais été investigué. De plus, comme les astrocytes forment des réseaux bien définis dans le NVsnpr, nous avons émis l’hypothèse que l’activation de ces réseaux pourrait contribuer à synchroniser l’activité rythmique de groupes de neurones. Pour investiguer ces deux questions, nous avons utilisé des enregistrements en mode cellules entières de neurones et d’astrocytes du NVsnpr lors de stimulations optogénétiques des astrocytes chez des souris transgéniques. Différentes lignées de souris transgéniques ont été utilisées pour exprimer des protéines photosensibles comme la channelrhodopsin (ChR2) ou le récepteur adrénergique α-1 dans les astrocytes du NVsnpr dans le but de pouvoir les stimuler par l’exposition à la lumière. De ces lignées, seul le croisement de souris S100β-Cre à des souris ChR2-lox donna des réponses significatives. Ces résultats démontrent que la stimulation optogénétique des astrocytes du NVsnpr cause divers effets sur la décharge neuronale, dont la genèse de bouffées rythmiques. Cependant, l’enregistrement de paires de neurones n’a pas permis de confirmer l’implication des astrocytes dans la synchronisation de l’activité rythmique des neurones de NVsnpr. Ces résultats permettent d’affiner les méthodes d’études des astrocytes dans le système trigéminal ainsi que de confirmer l’implication des astrocytes dans une activité rythmique, une implication qui pourrait potentiellement être observée dans d’autres structures du système nerveux central comme les GPCs de la locomotion ou de la respiration. / Several cerebral functions depend on the capacity of neural network to generate a rhythmic activity. One prominent example of this is the neural networks, named central pattern generators (CPGs), controlling repetitive movements patterns like locomotion, breathing and chewing. Previous studies have shown that the trigeminal main sensory nucleus (NVsnpr), which is part of the masticatory CPG, contains neurons that can rhythmically discharge and that the astrocytes and their protein, S100β, were essential for this neuronal rhythmogenesis. However, the effect of the activation of astrocytes on neuronal discharge of the NVsnpr remains uninvestigated. Additionally, since astrocytes form well-defined networks in the NVsnpr, we hypothesized that the activation of these networks could help synchronize the rhythmic activity of groups of neurons. To investigate these questions, we used whole cell recordings of neurons and astrocytes of the NVsnpr during optogenetic stimulation of astrocytes in transgenic mice. Different mice strains have been used to express photosensitive proteins such as channelrhodopsin (ChR2) or the α-1 adrenegic receptor in NVsnpr astrocytes to enable their stimulation with light. Of all these strains, only the S100β-Cre X ChR2-lox hybrids provided significant responses. Optogenetic stimulation of NVsnpr astrocytes produced various effects on neuronal discharge, including the genesis of rhythmic bursts. However, the recording of pairs of neurons did not confirm the involvement of astrocytes in the synchronization of the rhythmic activity of NVsnpr neurons. These results contribute to the refinement of methods used to study astrocytes in the trigeminal system and confirm the involvement of astrocytes in rhythmogenesis, an involvement that could be observed in other structures of the central nervous system such as the CPGs for respiration or locomotion.

No description available.