Resumo: Os dados sobre a influência da forma do rebordo alveolar na distribuição interna das tensões na associação da prótese parcial removível de extremidade livre (PPREL) com os implantes osseointegrados são inconclusivos. Assim, o objetivo deste estudo foi avaliar através do método dos elementos finitos (MEF) bi-dimensional, a influência do formato do rebordo alveolar na distribuição interna das tensões. Para isso, foram confeccionados 12 (doze) modelos no programa AutoCAD 2005 (Autodesk Inc, USA), sendo: Modelo A (MA) - hemiarcada com a representação do dente natural 33 e o rebordo edentado para distal; Modelo B (MB) - semelhante ao MA com uma PPREL convencional substituindo os dentes ausentes 34, 35, 36 e 37; Modelo C (MC) - semelhante ao MB, porém com um implante do Sistema Bränemark (3,75 x 10,0 mm) posicionado na região retromolar, sob a base da prótese, conferindo apenas suporte; Modelos A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 e C4 foram baseados nos respectivos modelos: A, B e C, com a identificação numérica seguindo a forma do rebordo alveolar no plano sagital, como descrito: descendente distal (1), côncavo (2), plano (3) e ascendente distal (4). Os modelos foram exportados para o programa de elementos finitos ANSYS 8.0 (Swanson Analysis Systems, Houston, Pa) para a análise numérica. O carregamento foi realizado com forças verticais de 50 N. Os resultados mostraram que máxima tendência ao deslocamento para os rebordos analisados ocorreu de forma semelhante entre os modelos B e C, sendo: descendente distal (B1 - 0,2484 mm e C1- 0,2513 mm), plano (B3 - 0,2415 mm e C3 0,2452 mm), côncavo (B2 - 0,2377 mm e C2 0,2392 mm) e ascendente distal (B4 - 0,2255 mm e C4 - 0,2293 mm); a máxima concentração de tensão nos modelos B apresentou a seguinte ordem: descendente distal (288,77 MPa), côncavo (199,99 Mpa), plano (197,11 MPa) e ascendente distal (185,22 MPa)... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: The data about the influence of the alveolar ridge shape in the stress distribution during the association of a free-end saddle removable partial denture (FERPD) with an osseointegrated implant are inconclusive. Thus, the objective of this study was to evaluate, by bidimensional the finite element analysis (FEA), the influence of the alveolar ridge shape in the stress distribution. For this, 12 (twelve) models were created in the program AutoCAD 2005 (Autodesk Inc, USA), representing: model A (MA) - hemiarch containg only the natural tooth 33 and edentulous space for distal; model B (MB) - similar to MA with a conventional FERPD replaying the absent teeth 34, 35, 36 and 37; model C (MC) - similar to MB, however with an implant of the Sistema Bränemark (3,75 x 10,0 mm) positioned in posterior area, in order to support FERPD base; Models A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 were based on the respective models: A, B and C, with the numeric identification following the shape in the sagital plane, as described: distal descending (1), concave (2), plan (3) and distal ascendancy (4). The models were exported for the FEA hardware (ANSYS 8.0 Swanson Analysis Systems, Houston, PA) for numeric analysis. The loading were performance with vertical forces of 50 N. The results showed maximum displacement tendency (mm) were between models B and C: distal descending (B1 - 0.2484 mm and C1 - 0.2513 mm), plan (B3 - 0.2415 mm and C3 0.2452 mm), concave (B2 - 0.2377 mm and C2 0.2392 mm) and distal ascendancy (B4 - 0.2255 mm and C4 - 0.2293 mm); the maximum stress concentration for models B were distal descending (288,77 MPa), concave (199,99 MPa), plan (197,11 MPa) and distal ascendancy (185,22 MPa); the model C present an inversion between plan and distal ascending shape: C1 with 395,93 MPa, C2 with 341,49 MPa, C4 with 266,02 MPa and C3 with 219,58 MP... (Complete abstract, click electronic address below). / Orientador: Eduardo Passos Rocha / Coorientador: João Antônio Pereira / Banca: Eduardo Piza Pellizzer / Banca: Renata Cunha Matheus Rodrigues Garcia / Mestre

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Imagens de tomografia computadorizada (TC) permitem a visualização, sem distorções ou sobreposições, do complexo maxilo-facial, principalmente do osso alveolar. Estudos demonstraram boa reprodutibilidade e precisão da mensuração da altura da borda alveolar, todavia a influência da espessura óssea ainda é pouco descrita. Através da comparação com a mensuração direta, o objetivo deste estudo foi avaliar a precisão, reprodutibilidade e a influência da espessura óssea, na mensuração da altura da borda alveolar em imagens volumétricas e imagens bidimensionais multiplanares em TC de feixe cônico (TCFC) e em TC espiral (TCE). Utilizando 10 mandíbulas secas de humanos, 57 dentes anteriores foram tomografados em equipamentos iCAT (Imaging Science International, Hatfield, PA, EUA) e Brilliance 64 canais (Philips Eletronics, Eindhoven, Holanda), ambos utilizando voxels de 0,25 mm. Através de imagens volumétricas (3D) e imagens bidimensionais (2D) de cortes multiplanares, foi comparada a mensuração da altura da borda alveolar dessas imagens com a mensuração direta nas mandíbulas, feita por vestibular e lingual, por três avaliadores, com o auxílio de um paquímetro, totalizando 114 bordas alveolares medidas. Alta reprodutibilidade intra-avaliador (0,999 a 0,902) e interavaliador (0,998 e 0,868) foi observada através do índice de correlação intraclasse (ICC). Observou-se alta correlação entre a mensuração direta e indireta da altura da borda alveolar em imagens 2D, sendo r=0,923** e 0,916**, e em imagens 3D, com r=0,929** e 0,954*, em TCFC e TCE, respectivamente. Imagens 2D superestimam a altura da borda alveolar em 0,32 e 0,49 mm e imagens 3D em 0,34 e 0,30 mm, em TCFC e TCE respectivamente. Quando o osso alveolar apresenta espessura de no mínimo 0,6 mm a média da diferença entre medidas diretas e indiretas é de 0,16 e 0,28 mm em imagens 2D e de 0,12 e 0,03 mm em imagens 3D para TCFC e TCE respectivamente, sendo que 95% do limite de concordância varia de -0,46 a 0,79 mm e -0,32 a 0,88 mm em imagens 2D, e de -0,64 a 0,67 mm e -0,57 a 0,62 mm em imagens 3D, para TCFC e TCE respectivamente. Quando o osso alveolar é mais fino do que 0,6 mm a TC é imprecisa, pois 95% do limite de concordância variou de -1,74 a 5,42 mm e -1,64 a 5,42 mm em imagens 2D, e de -3,70 a 4,28 mm e -3,49 a 4,25 mm em imagens 3D, para TCFC e TCE respectivamente. Conclui-se que a mensuração da altura da borda alveolar através de imagens tomográficas apresenta alta reprodutibilidade, sendo que quando a borda alveolar apresenta pelo menos 0,6 mm, a precisão da mensuração é alta, todavia quando esta espessura é menor do que 0,6 mm a técnica é imprecisa. / Computerized tomogoraphy (CT) images allow for visualization, with no distortions or superimpostions, of the maxillo-facial complex, especially of the alveolar margins. Studies have demonstrated good reproducibility and precision of the alveolar bone height, however the influence of bone thickness is still scarcely described. The purpose of this study was, by comparing the direct measurement of alveolar bone height, to evaluate the precision, reproducibility and the influence of bone thickness on the same measurement in cone beam CT (CBCT) and spiral CT (SCT) volumetric and biplane images. Ten dry human mandibles, with a total of 57 anterior teeth were tomographed with an iCAT (Imaging Science International, Hatfield, PA, EUA) and a 64 channels Brilliance 64 tomograph (Philips Eletronics, Eindhoven, Holland), both using voxels of 0.25 mm. Alveolar bone height was measured on volumetric (3D) and bidimensional (2D) images of tomograms and compared with direct caliper measurements performed on the dry mandibles, on the buccal and lingual sides, by three raters in a total of 114 measurements. High intra-rater (0.999 a 0.902) and inter-rater (0.998 e 0.868) reproducibility was observed using the intraclass correlation coefficient (ICC). A high correlation was also observed between the direct and indirect measurements of alveolar bone height in 2D (r=0.923** e 0.916**), and 3D images (r=0.929** e 0.954*), for CBCT and SCT, respectively. Two-dimensional images overestimate alveolar bone height in 0.32 and 0.49 mm and 3D images in 0.34 and 0.30 mm, for CBCT and SCT, respectively. When alveolar bone thickness is at least 0.6 mm the mean difference is of 0.16 and 0.28 mm in 2D images and of 0.12 and 0.03 mm in 3D images for CBCT and SCT, respectively, with 95% limits of agreement ranging from -0.46 to 0.79 mm and -0.32 to 0.88 mm in 2D images, and of -0.64 to 0.67 mm and -0.57 to 0.62 mm in 3D images, for CBCT and SCT, respectively. When alveolar bone thickness is smaller than 0.6 mm CT evaluation is inaccurate, since 95% limits of agreement vary from -1.74 to 5.42 mm and -1.64 to 5.42 mm in 2D images, and from -3.70 to 4.28 mm and -3.49 to 4.25 mm on 3D images, for CBCT and SCT, respectively. It can be concluded that measurement of alveolar bone height on CT images presents high reproducibility. When alveolar bone thickness is greater than 0.6 mm measurement precision is high, and when this thickness is less than 0.6 mm the technique is inaccurate

Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-27T17:05:59Z No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-27T18:54:00Z (GMT) No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-27T18:54:00Z (GMT). No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Composite beams of steel and concrete are studied for some time. The mechanism of transfer of longitudinal shear stresses on the interface between the beam and the slab usually occurs by means of shear connectors. In this case, the set of two materials behavior depends on the strength and rigidity of the connector on the interface, being well known for connectors with pin-type head associated with massive concrete slab. However, there is little information on shear connectors with pin-type head associated with hollowcore slab concrete. This study aims to determine, by means of direct shear tests, the resistance of connectors with pin-type head when associated with cellular slab and precast concrete presence of cover concrete. Hollow core slabs are analyzed with two different heights and concrete cover of 40 mm in thickness. Is also varied the strength of concrete fill and rate of shear reinforcement at the link. The results are compared with normative prescriptions and suggestions for other jobs. At the end, we propose the modification of an expression commonly used to evaluate the resistance of stud bolt and alveolar slab so as to adapt it to the situation of cellular concrete slab with hood. / As vigas mistas de aço e concreto são estudadas há bastante tempo. O mecanismo de transferência de tensões de cisalhamento longitudinais pela interface entre a viga e a laje normalmente se dá por meio de conectores de cisalhamento. Nesse caso, o comportamento conjunto dos dois materiais depende da resistência e da rigidez do conector na interface, sendo bem conhecido para os conectores do tipo pino com cabeça associados com laje maciça de concreto. Entretanto, há pouca informação sobre conectores de cisalhamento do tipo pino com cabeça associados com laje alveolar de concreto pré-moldado. Este trabalho tem por objetivo determinar, por meio de ensaios de cisalhamento direto, a resistência de conectores do tipo pino com cabeça quando associados com laje alveolar de concreto pré-moldado e presença de capa de concreto. São analisadas lajes alveolares com duas alturas diferentes e capa de concreto de 40 mm de espessura. Também é variada a resistência do concreto de preenchimento e a taxa de armadura transversal à ligação. Os resultados são comparados com prescrições normativas e sugestões de outros trabalhos. Ao final, é proposta a modificação de uma expressão normalmente utilizada para avaliar a resistência do conector tipo pino com cabeça e laje alveolar de modo a adequá-la à situação de laje alveolar com capa de concreto.

A doença periodontal é caracterizada por alterações inflamatórias, como vermelhidão e edema da margem gengival, sangramento provocado, alterações no contorno gengival e perda óssea alveolar. Evidências recentes sugerem que o fator de crescimento endotelial vascular (VEGF) pode ser um mediador importante na doença periodontal inflamatória. Portanto, este trabalho teve como objetivos avaliar durante a progressão da doença periodontal inflamatória induzida experimentalmente em ratos: 1) o efeito do meloxicam, inibidor preferencial da COX-2, na perda óssea alveolar; 2) a cinética de expressão de RNAm para COX-2, VEGF, VEGFR-1 e VEGFR-2; e 3) a cinética de expressão da proteína VEGF. Cento e vinte (120) ratos foram aleatoriamente divididos em: grupo 1 (sem tratamento com meloxicam) e grupo 2 (tratados com meloxicam). Ligaduras de fio de seda foram colocadas na margem gengival do primeiro molar inferior direito de todos os ratos. O grupo 2 foi tratado por 3, 7, 14 e 30 dias com meloxicam (3 mg/kg/dia, via intraperitoneal) e o grupo 1 foi usado como controle. As técnicas utilizadas para as análises foram: análise microscópica, RT-PCR, Western Blot e imunohistoquímica. Os resultados foram submetidos à análise de Correlação de Pearson, Análise de Variância (ANOVA), seguida do teste de Tukey, sendo adotado nível de significância de 5%. Observou-se, neste estudo, que o meloxicam foi efetivo em diminuir a perda óssea alveolar nos tecidos periodontais em todos os períodos de indução da doença periodontal. Experimentos de RT-PCR revelaram correlação positiva da cinética de expressão de RNAm para COX-2 e VEGF nos tecidos gengivais afetados pela doença periodontal inflamatória (R=0,80). A expressão de RNAm para VEGF na doença periodontal inflamatória, no período de 14 dias, diminuiu no grupo de animais tratados com meloxicam, mostrando diferença estatisticamente significativa quando comparado com os animais não tratados (p=0,023). Não houve diferença significativa na expressão de RNAm para os receptores VEGFR-1 e VEGFR-2 no tecido gengival em nenhum dos períodos de indução da doença periodontal. Nos experimentos de Western Blot houve tendência de menor expressão da proteína VEGF na doença periodontal inflamatória no período de 14 dias nos animais tratados com meloxicam (p=0,08). Em experimentos de imunohistoquímica foi detectado aumento da expressão da proteína VEGF nos tecidos afetados pela doença periodontal em todos os períodos estudados, bem como diminuição da expressão desta proteína nos tecidos periodontais dos animais tratados com meloxicam. Portanto, a análise conjunta dos dados sugere importante participação do VEGF na doença periodontal inflamatória induzida experimentalmente em ratos e o meloxicam, inibidor preferencial da COX-2, pode modificar a progressão da doença periodontal neste modelo experimental por diminuir a perda óssea e a expressão de VEGF. / Inflammatory periodontal disease is characterized by alveolar bone loss and inflammatory changes in the periodontal tissues, which become hemorrhagic and edematous. However, there is little information concerning the biologic mechanisms which may produce these changes. Vascular endothelial growth factor (VEGF) is a macromolecule of importance in inflammation. The aims of this study were to investigate the presence of VEGF during progression of periodontal disease, and to evaluate the effect of a preferential COX-2 inhibitor, meloxicam, on the alveolar bone loss and VEGF expression in experimentally induced periodontitis. One hundred and twenty (120) Wistar rats were randomly separated into two groups [group 1 (no treatment with meloxicam) and group 2 (treatment with meloxicam)]. Silk ligatures were placed at the gingival margin level of the lower right first molar of all rats. Group 2 was treated for 3, 7, 14 and 30 days with meloxicam (3 mg/kg/day, intraperitoneal) and the group 1 was used as control. The expression of VEGF was assessed by RT-PCR, Western Blot and immunohistochemical analysis. Alveolar bone loss was determined by microscopic analysis. The results were submitted to the analysis of Correlation Coefficient by Pearson, Analysis of Variance (ANOVA), and Tukey\'s post test (p<0.05). A reduction of the alveolar bone resorption was observed in the meloxicam treated group (2), as compared with the control group (1) in all periods studied. There was a positive correlation between COX- 2 mRNA and VEGF mRNA in the gingival tissue with periodontal disease (R=0.80). VEGF mRNA expression was significantly lower in rats treated with meloxiam after 14 days (p=0.023). No difference in the expression of VEGFR-1 mRNA and VEGFR-2 mRNA was observed for all the periods studied. VEGF protein expression was significantly higher in diseased sites as compared with healthy sites (p<0.05). After 14 days lower VEGF protein expression in rats treated with meloxicam was detected (p=0.08). Altogether these data suggest an important participation of VEGF in the progression of periodontal disease, and the systemic therapy with meloxicam, preferential COX-2 inhibitor, can modify the progression of experimentally induced periodontitis in rats by reducing the alveolar bone loss and the VEGF expression.

Thoracic surgical procedures require partial or complete airway separation and the opportunity to exclude one lung from ventilation (one-lung ventilation, OLV). OLV is commonly associated with profound pathophysiological changes that may affect the postoperative outcome. It is injurious in terms of increased mechanical stress including alveolar cell stretch and overdistension, shear forces secondary to repeated tidal collapse and reopening of alveolar units and compression of alveolar vessels. Ventilation and perfusion distribution may thus be affected during and after OLV. The present studies investigated the influence of OLV on ventilation and perfusion distribution, on the gas/tissue distribution and on the lung histomorphology in a pig model of thoracic surgery. Anaesthetised and mechanically ventilated piglets were examined. The ventilation and perfusion distribution within the lungs was assessed by single photon emission computed tomography. Computed tomography was used to establish the effects of OLV on dependent lung gas/tissue distribution. The pulmonary histopathology of pigs undergoing OLV and thoracic surgery was compared with that of two-lung ventilation (TLV) and spontaneous breathing. OLV induced hyperperfusion and significant V/Q mismatch in the ventilated lung persistent in the postoperative course. It increased cyclic tidal recruitment that was associated with a persistent increase of gas content in the ventilated lung. OLV and thoracic surgery as well resulted in alveolar damage.  In the present model of OLV and thoracic surgery, alveolar recruitment manoeuvre (ARM) and protective ventilation approach using low tidal volume preserved the ventilated lung density distribution and did not aggravate cyclic recruitment of alveoli in the ventilated lung. In conclusion, the present model established significant alveolar damage in response to OLV and thoracic surgery. Lung injury could be related to the profound pathophysiological consequences of OLV including hyperperfusion, ventilation/perfusion mismatch and increased tidal recruitment of lung tissue in the dependent, ventilated lung.  These mechanisms may contribute to the increased susceptibility for respiratory complications in patients undergoing thoracic surgery. A protective approach including sufficient ARM, application of PEEP, and the use of lower tidal volumes may prevent the ventilated lung from deleterious consequences of OLV.

No description available.

Bronchopulmonary dysplasia (BPD) is a chronic neonatal lung injury (CNLI) affecting infants of < 32 weeks gestation, which has a significant associated morbidity and mortality. The hallmarks of BPD as seen in the current era are arrested alveologenesis and parenchymal thickening. Those most severely affected may develop pulmonary hypertension which worsens the prognosis. No effective preventive therapy exists. Generation of damaging reactive oxygen species is implicated in its development. The more recently recognized reactive nitrogen species may also contribute to this disease. Thus, there is considerable interest in preventive antioxidant therapies, but results to date have not been promising. Newborn rats, exposed to 60% O2 for 14 days, develop a parenchymal injury and pulmonary hypertension that resembles the morphological features of human BPD. Previous studies have shown that following exposure to 60% O2, a pulmonary influx of neutrophils is followed by that of macrophages. Inhibiting the influx of neutrophils prevents the generation of reactive oxygen species, while simultaneously enhancing postnatal lung growth. Other interventions have shown that development of pulmonary hypertension is dependent upon increases in both 8-isoprostane and its downstream regulator of vascular tone, endothelin-1. Gentler ventilation strategies, incorporated to minimize induction of stretch-mediated pro-inflammatory cytokines, have shown benefits of permissive hypercapnia in adult lung injury. Multicentre clinical trials of permissive hypercapnia in neonates have not shown benefit. Therapeutic hypercapnia has been demonstrated to have a protective effect of PaCO2 in both acute studies of ventilator-induced and ischemia-reperfusion injuries in animal models. In the studies reported herein, therapeutic hypercapnia was found to completely protect against CNLI and attenuate 60% O2-induced macrophage-derived protein nitration. The likely nitrating agent was macrophage-derived peroxynitrite. The critical role of peroxynitrite, in the development of chronic neonatal lung injury in this model, was confirmed using a peroxynitrite decomposition catalyst. This protected against the impairments of alveolarization and of pulmonary vascularization induced by 60% O2. These results suggest a more significant role for reactive nitrogen species than previously recognized. Finally, preliminary evidence is presented supporting a role for neutrophil-derived elastase in initiating the macrophage influx in the lungs, required for peroxynitrite generation, during 60% O2-mediated injury.

La résorption post-extractionnelle est de nos jours une conséquence inéluctable après avulsion. Cette résorption, lors d'une réhabilitation prothétique sur implants, peut avoir des conséquences néfastes tant dans le résultat esthétique que fonctionnel. Les techniques de régénération pré-implantaire (technique dérivée de la régénération tissulaire guidée) par l'emploi d'autogreffe, de xénogreffe ou encore d'allogreffe associée ou non à une membrane ont montré des bénéfices quant à la préservation du volume osseux. Les délais d'ostéointégration ayant été de nos jours réduits avec un taux de survie implantaire satisfaisant, la technique d'extraction/implantation immédiate a été envisagée dans le but d'éviter la perte osseuse post-extractionnelle et réduire le temps de traitement. Toutefois, les études menées chez le chien par différents auteurs ont montré que cette technique ne permettait en aucun cas d'éviter la resorption post-extractionnelle. La mise en place précoce d'un implant dans une alvéole déshabitée permet seulement de limiter cette dernière. Le but de note étude animale a donc été, dans les cas d'extraction/implantation immédiate, d'évaluer la perte osseuse obtenue au travers des résultats tomodensitométriques et histovolumétriques, perte osseuse comparée, à celle mesurée dans les chirurgies de comblement ainsi que dans les chirurgies régénératives avec membranes positionnées en supra ou intra-alvéolaire. Nous avons également souhaité évaluer l'intérêt de la régénération osseuse guidée dans la préservation du volume osseux lorsqu'une prothèse sur implant est envisagée. Notre choix s'est porté sur une membrane collagénique résorbable qui ont montré au travers de nombreuses études certains avantages : biocompatibilité satisfaisante, exposition n'engendrant pas un échec de la chirurgie et enfin une résorbabilité évitant une chirurgie de dépose. Concernant le matériau de comblement, nous avons opté pour une allogreffe corticale afin d'évaluer la cicatrisation osseuse obtenue, la résorbabilité du matériau et la qualité de l'interface os/implant. Dans une première partie, nous ferons un rappel sur le tissu osseux et son remodelage après avulsion. La seconde partie sera consacrée aux techniques de préservation du volume osseux, la troisième partie faisant le point sur la technique d'extraction/implantation immédiate d'un point de vue cicatrisation osseuse. Enfin la quatrième et dernière partie sera consacrée à l'étude animale. / Post-extraction resorption is nowadays an inevitable consequence of teeth extraction. This loss, during prosthetic implant rehabilitation, strongly affects aesthetic and functional results.Guided bone regeneration, issue from the guided tissular regeneration, using autogenous bone, xenograft or still allograft associated or not with a barrier membrane shows benefits in the conservation of bone volume.The delays of osteointegration having nowadays been reduced with a good rate of implant survival; immediate extraction-implantation is supposed to avoid post-extraction resorption and to reduce overall treatment time. However, animal studies from many authors showed that this technique cannot avoid the post-extraction resorption. The immediate implantation only allows to reduce it.The purpose of our animal study was to estimate the bone loss for immediate extraction-implantation technique through the histotomodensimetric and histovolumetric measurements. Bone loses were compared for allogenic bone grafting associated or not with supra or intra alveolar barrier membranes. We investigate also the benefits of guided bone regeneration in the preservation of bone volume for delayed implantation. The parameters followed were the alveolar bone loss, the resorbability of the material and the quality of bone/ implant interface. We selected absorbable collagenic barrier membrane which have shown in numerous studies many advantages: good biocompatibility, exposure don't challenge clinical results and resorbability avoiding an additionnal removal surgery. Concerning the bone grafting material, we opted for a cortical allograft. In the first chapter, we made a review of the bone histology and physiology and of its remodeling after extraction. The second chapter is dedicated to alveolar bone preservation techniques and in the third chapter we reviewed immediate extraction-implantation surgical techniques from the point of view of bone healing. Finally the fourth part of our thesis is dedicated to the presentation and analysis of our animal study.

Objetivo: Avaliar a prevalência das manifestações clinicas, alterações laboratoriais e tratamento em um estudo de coorte multicêntrico incluindo 847 pacientes com diagnóstico de lúpus eritematoso sistêmico juvenil (LESJ) com ou sem hemorragia pulmonar (HP) assim como parâmetros de gravidade. Métodos: HP foi definida de acordo com a presença de pelo menos três sintomas/sinais respiratórios associados à imagem de infiltrado intersticial/alveolar difuso em radiografia de tórax e/ou tomografia computadorizada e queda aguda dos níveis de hemoglobina. Analise estatística foi realizada utilizando-se correção de Bonferroni (p < 0,0022). Resultados: HP foi observada em 19/847 (2,2%) dos pacientes com LESJ. Tosse, dispneia, taquicardia e/ou hipoxemia ocorreram em todos os pacientes com HP. Parâmetros de gravidade associados observados foram: ventilação mecânica em 14/19 (74%), hemoptise 12/19 (63%), síndrome de ativação macrofágica 2/19 (10%) e óbito 9/19 (47%). Análises de pacientes com LESJ ao diagnóstico de HP comparando-os com 76 pacientes controles com LESJ sem hemorragia pulmonar e com mesmo tempo de doença [3 (1-151) vs. 4 (1-151) meses, p=0,335], revelaram maior frequência de envolvimento constitucional (74% vs. 10%, p < 0,0001), serosite (63% vs. 6%, p < 0,0001) e sepse (53% vs. 9%, p < 0,0001) no grupo com HP. A mediana de escore de atividade de doença (SLEDAI-2K) foi significantemente maior em pacientes com LESJ com HP [18 (5-40) vs. 6 (0-44), p < 0,0001] assim como a mediana da dose de corticoide em uso em mg/Kg [1,4 (0,3-2) vs. 05 (0,03-3), p < 0,0001]. A frequência de plaquetopenia (53% vs. 12%, p < 0,0001), uso de metilprednisolona endovenosa (95% vs. 16%, p < 0,0001) e ciclofosfamida endovenosa (47% vs. 8%, p < 0,0001) também foi significantemente maior em pacientes com HP. Conclusões: Pacientes com LESJ apresentaram baixa prevalência de HP. Pacientes com LESJ e HP tiveram uma doença ativa grave, sistêmica, associada a envolvimento constitucional, serosite, plaquetopenia, sepse, dose maior de manutenção de corticoide, e principalmente tratada com pulsoterapia de corticoide e ciclofosfamida endovenosa / Objective: To evaluate prevalence, clinical manifestations, laboratory abnormalities and treatment in a multicenter cohort study including 847 childhood-onset systemic lupus erythematosus (cSLE) patients with and without diffuse alveolar hemorrhage (DAH), as well as concomitant parameters of severity. Methods: DAH was defined as the presence of at least three respiratory symptoms/signs associated with diffuse interstitial/alveolar infiltrates on chest x-ray or high-resolution computer tomography and sudden drop in hemoglobin levels. Statistical analysis was performed using Bonferroni correction (p < 0.0022). Results: DAH was observed in 19/847 (2.2%) cSLE patients. Cough/dyspnea/tachycardia/hypoxemia occurred in all cSLE patients with DAH. Concomitant parameters of severity observed were: mechanical ventilation in 14/19 (74%), hemoptysis 12/19 (63%), macrophage activation syndrome 2/19 (10%) and death 9/19 (47%). Further analysis of cSLE patients at DAH diagnosis compared to 76 cSLE control patients without DAH with same disease duration [3 (1-151) vs. 4 (1-151) months, p = 0.335], showed higher frequencies of constitutional involvement (74% vs. 10%, p < 0.0001), serositis (63% vs. 6%, p < 0.0001) and sepsis (53% vs. 9%, p < 0.0001) in the DAH group. The median of disease activity score(SLEDAI-2 K) was significantly higher in cSLE patients with DAH [18 (5-40) vs. 6 (0-44), p < 0.0001]. The frequencies of thrombocytopenia (53% vs. 12%, p < 0.0001), intravenous methylprednisolone (95% vs. 16%, p < 0.0001) and intravenous cyclophosphamide (47% vs. 8%, p < 0.0001) were also significantly higher in DAH patients. Conclusions: cSLE patients have shown low prevalence of DAH. Patients with both cSLE and DAH had serious, active systemic disease, associated with constitutional involvement, serositis, thrombocytopenia, sepsis, higher doses of maintenance corticotherapy, and mostly treated with corticoid pulse therapy and intravenous cyclophosphamide

A maioria dos edifícios de concreto pré-moldado, construídos no Brasil e no exterior, é constituída por lajes alveolares. Este trabalho considera o estudo da continuidade dessas lajes. No cálculo desses elementos, a prática comum é considerá-los como simplesmente apoiados. Para melhorar o desempenho, é possível promover a continuidade nos apoios intermediários. Isso pode ser feito colocando armadura na região tracionada da ligação, no interior da capa, ou através de barras concretadas dentro dos alvéolos. O objetivo deste trabalho é investigar o comportamento de pavimentos formados por lajes alveolares com continuidade, com armadura na capa. Para isso, foi realizado um estudo envolvendo análise teórica e experimental em três modelos. Esses modelos, em escala real, foram submetidos a um carregamento transversal, distribuído de forma linear. Os estudos teóricos consideraram uma simulação numérica com elementos de viga e a fórmula de Branson para descrever o comportamento não linear físico do material. Além disso, foram avaliadas as expressões dos principais códigos nacionais e internacionais, no que diz respeito à ruptura por cisalhamento da seção transversal e da interface laje-capa. Os resultados da análise experimental indicaram que o modelo 1 rompeu por cisalhamento da seção transversal, com o mecanismo de tração diagonal do concreto. O modelo 2 apresentou ruptura por cisalhamento da interface. No modelo 3, a ruptura foi por flexão. O comportamento dos modelos ensaiados foi governado pela fissuração da capa na região de momento negativo. A análise teórica com elementos de barra representou de forma satisfatória o comportamento dos modelos ensaiados. As únicas formulações que apresentaram resultados coerentes com os três ensaios foram: EUROCODE 2:2004, para o cálculo da resistência ao cisalhamento da interface, e FIB MODEL CODE 2010, para o cálculo da resistência ao cisalhamento da seção transversal. Conclui-se que a continuidade melhora o desempenho das lajes alveolares, uma vez que reduz os deslocamentos no meio do vão e aumenta a capacidade de carga. / Most buildings of precast concrete built in Brazil and abroad consist of hollow core slabs. This paper considers the study of the continuity of these slabs. In design of these elements the common practice is to consider them as simply supported. To improve the performance it is possible to promote the continuity in the intermediate supports. This can be done by placing reinforcement in the tensioned region of the connection, inside the topping, or by bars concreted inside the voids. The aim of this work is to investigate the behavior of hollow core floors with continuity, with reinforcement in the topping. For this, a study involving theoretical and experimental analysis was conducted in three models. The full-scale models were subjected to a transverse loading distributed linearly. The theoretical studies have considered a numerical simulation with beam elements and the Branson formula to describe the physical nonlinear behavior of the material. Furthermore, the specifications of the major Brazilian and international codes were evaluated, with respect to failure by shear of the cross section and the slab-topping interface. The results of the experimental analysis indicated that the model 1 failed by shear of the cross section with the mechanism of diagonal tension of the concrete. Model 2 presented shear failure of the interface. In model 3, the failure was by flexure. The behavior of the tested models was ruled by cracking of the topping in region of negative bending moment. Theoretical analysis with beam elements represented satisfactorily the behavior of the tested models. The only formulations that presented consistent results with the three tests were: EUROCODE 2:2004, to calculate the shear strength of the interface, and FIB MODEL CODE 2010, for calculating of the shear strength of the cross section. It is concluded that the continuity improves the performance of the hollow core slabs, as it reduces the displacements at mid-span and increases the bearing capacity.