Introdução: Os objetivos deste estudo foram comparar a extrusão apical de debris durante a desobturação com WaveOne Gold, ProTaper retratamento, D-RaCe ou limas manuais; descrever as falhas e/ou fraturas ocorridas nos instrumentos de NiTi; e comparar o WaveOne Gold com os sistemas ProTaper e RaCe em relação à quantidade de material obturador remanescente, transporte apical (TA) e tempo de trabalho após a desobturação e após o repreparo de canais radiculares curvos. Materiais e Métodos: Quarenta canais mésiovestibulares de molares superiores foram preparados, obturados e divididos em 4 grupos (n=10): WOG) WaveOne Gold Primary e Medium; PTG) ProTaper Retreatmento e ProTaper Next; RCG) D-RaCe e RaCe; e LM) Limas manuais. A extrusão de debris foi determinada subtraindo-se o peso final do peso inicial dos Eppendorfs. Os instrumentos de NiTi (n=18) foram analisados em MEV antes e após a desobturação. A quantidade de material obturador remanescente e o TA foram avaliados em micro-TC. O tempo de trabalho foi anotado e comparado. Os dados foram estatisticamente analisados (α=.05). Resultados: WOG extruiu menos debris do que LM e RCG (P<.05), e foi similar ao PTG (P>.05). Não houve diferença entre LM, PTG e RCG (P>.05). A análise em MEV mostrou, dos 18 instrumentos avaliados, 3 fraturas e 10 deformações. Nas duas etapas avaliadas, WOG apresentou similar (P>.05) e menor (P<.05) quantidade de material obturador remanescente do que PTG e RCG, respectivamente. A quantidade de material no WOG e RCG foi menor após o repreparo (P<.05). Na desobturação, WOG teve maior TA em 4mm do que em 2mm (P<.05). Em 2mm, o TA do WOG foi menor do que RCG (P<.05), e em 4mm foi igual ao PTG e RCG (P>.05). Na desobturação, o tempo de trabalho no grupo LM foi maior que nos demais (P<.05). No repreparo, WOG foi mais rápido do que PTG e RCG (P<.05). Conclusões: Todos os instrumentos causaram extrusão de debris, sendo que o WOG apresentou os menores valores. Nenhum sistema removeu completamente o material obturador de raízes mésiovestibulares de molares superiores. Considerando os baixos valores de TA obtidos, os instrumentos avaliados foram considerados seguros para desobturação e repreparo de canais curvos. A desobturação com LM foi mais lenta do que com os instrumentos de NiTi. O sistema reciprocante foi mais rápido do que os rotatórios no reprepro. / Introduction: The aims of this study were to assess the amount of apically extruded debris during filling removal with WaveOne Gold, ProTaper Retreatment, D-RaCe or hand files; to describe failures of NiTi instruments; and to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT) and working time after filling removal and after shaping of curved root canals. Methods: Forty mesiobuccal canals of maxillary molars were prepared, filled, and assigned into 4 groups (n=10): WOG) WaveOne Gold Primary and Medium; PTG) ProTaper Retreatment and ProTaper Next; RCG) D-RaCe and RaCe; HF) Hand files. The amount of extruded debris was determined by subtracting the final from the initial Eppendorfs weight. The NiTi instruments (n=18) used for filling removal were analyzed pre and post-operatively by SEM. Micro-CT analysis assessed the residual filling material and AT. Working time was recorded and compared. Data were statistically analyzed (α=.05). Results: WOG produced less debris compared with HF and RCG (P<.05), and similar to PTG (P>.05). HF, PTG and RCG showed no difference (P>.05). SEM analyses after filling removal showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. In both evaluated steps, WOG had similar (P>.05) and less (P<.05) amount of filling material as PTG and RCG, respectively. The remaining material in WOG and RCG was lower after shaping (P<.05). In filling removal, WOG had higher AT at 4mm than at 2mm (P<.05). At 2mm, AT of WOG was lower than RCG (P<.05), and at 4mm, was equal to PTG and RCG (P>.05). In filling removal, working time in HF group was significantly higher than others (P<.05). In shaping step WOG was faster than PTG and RCG (P<.05). Conclusions: All instruments tested caused debris extrusion, with WOG presenting the lowest values. Neither system could completely remove the filling material of mesiobuccal canals of maxillary molars. Considering the low AT values obtained, the instruments evaluated were safe for filling removal and shaping of curved canals. Filling removal with HF was slower than with the NiTi files. The reciprocating system was faster than the rotary in shaping the root canals.

Introdução: Os objetivos deste estudo foram comparar a extrusão apical de debris durante a desobturação com WaveOne Gold, ProTaper retratamento, D-RaCe ou limas manuais; descrever as falhas e/ou fraturas ocorridas nos instrumentos de NiTi; e comparar o WaveOne Gold com os sistemas ProTaper e RaCe em relação à quantidade de material obturador remanescente, transporte apical (TA) e tempo de trabalho após a desobturação e após o repreparo de canais radiculares curvos. Materiais e Métodos: Quarenta canais mésiovestibulares de molares superiores foram preparados, obturados e divididos em 4 grupos (n=10): WOG) WaveOne Gold Primary e Medium; PTG) ProTaper Retreatmento e ProTaper Next; RCG) D-RaCe e RaCe; e LM) Limas manuais. A extrusão de debris foi determinada subtraindo-se o peso final do peso inicial dos Eppendorfs. Os instrumentos de NiTi (n=18) foram analisados em MEV antes e após a desobturação. A quantidade de material obturador remanescente e o TA foram avaliados em micro-TC. O tempo de trabalho foi anotado e comparado. Os dados foram estatisticamente analisados (α=.05). Resultados: WOG extruiu menos debris do que LM e RCG (P<.05), e foi similar ao PTG (P>.05). Não houve diferença entre LM, PTG e RCG (P>.05). A análise em MEV mostrou, dos 18 instrumentos avaliados, 3 fraturas e 10 deformações. Nas duas etapas avaliadas, WOG apresentou similar (P>.05) e menor (P<.05) quantidade de material obturador remanescente do que PTG e RCG, respectivamente. A quantidade de material no WOG e RCG foi menor após o repreparo (P<.05). Na desobturação, WOG teve maior TA em 4mm do que em 2mm (P<.05). Em 2mm, o TA do WOG foi menor do que RCG (P<.05), e em 4mm foi igual ao PTG e RCG (P>.05). Na desobturação, o tempo de trabalho no grupo LM foi maior que nos demais (P<.05). No repreparo, WOG foi mais rápido do que PTG e RCG (P<.05). Conclusões: Todos os instrumentos causaram extrusão de debris, sendo que o WOG apresentou os menores valores. Nenhum sistema removeu completamente o material obturador de raízes mésiovestibulares de molares superiores. Considerando os baixos valores de TA obtidos, os instrumentos avaliados foram considerados seguros para desobturação e repreparo de canais curvos. A desobturação com LM foi mais lenta do que com os instrumentos de NiTi. O sistema reciprocante foi mais rápido do que os rotatórios no reprepro. / Introduction: The aims of this study were to assess the amount of apically extruded debris during filling removal with WaveOne Gold, ProTaper Retreatment, D-RaCe or hand files; to describe failures of NiTi instruments; and to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT) and working time after filling removal and after shaping of curved root canals. Methods: Forty mesiobuccal canals of maxillary molars were prepared, filled, and assigned into 4 groups (n=10): WOG) WaveOne Gold Primary and Medium; PTG) ProTaper Retreatment and ProTaper Next; RCG) D-RaCe and RaCe; HF) Hand files. The amount of extruded debris was determined by subtracting the final from the initial Eppendorfs weight. The NiTi instruments (n=18) used for filling removal were analyzed pre and post-operatively by SEM. Micro-CT analysis assessed the residual filling material and AT. Working time was recorded and compared. Data were statistically analyzed (α=.05). Results: WOG produced less debris compared with HF and RCG (P<.05), and similar to PTG (P>.05). HF, PTG and RCG showed no difference (P>.05). SEM analyses after filling removal showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. In both evaluated steps, WOG had similar (P>.05) and less (P<.05) amount of filling material as PTG and RCG, respectively. The remaining material in WOG and RCG was lower after shaping (P<.05). In filling removal, WOG had higher AT at 4mm than at 2mm (P<.05). At 2mm, AT of WOG was lower than RCG (P<.05), and at 4mm, was equal to PTG and RCG (P>.05). In filling removal, working time in HF group was significantly higher than others (P<.05). In shaping step WOG was faster than PTG and RCG (P<.05). Conclusions: All instruments tested caused debris extrusion, with WOG presenting the lowest values. Neither system could completely remove the filling material of mesiobuccal canals of maxillary molars. Considering the low AT values obtained, the instruments evaluated were safe for filling removal and shaping of curved canals. Filling removal with HF was slower than with the NiTi files. The reciprocating system was faster than the rotary in shaping the root canals.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / X-linked hypophosphatemic rickets (XLHR) is the most common cause of heritable rickets, with an incidence of 1:20,000 live births, representing more than 80% of familial hypophosphatemic rickets. Saliva is the most easily available and accessible body fluid, which makes it one of the most sought after tools in diagnostic pathology. In this context, this thesis, constituted by 4 articles aimed to: (1) describe the main systemic manifestations, oral findings and dental management in 3 generations of an affected family; (2) analyze the mineralization pattern of enamel and dentin in patients affected by XLHR using micro-CT, and to associate enamel and dentin mineralization in primary and permanent teeth with tooth position, gender and presence/absence of this disease; (3) evaluate the peptide profile in the saliva of patients with X-linked hypophosphatemic rickets using high performance liquid chromatography; and (4) characterize salivary proteins in this condition using unidimensional electrophoresis. On study 1, oral exams, laboratorial and histologic evaluations, cone-beam computed tomographies, panoramic and periapical radiographs were performed to properly institute the most adequate treatment strategy. On study 2, teeth were collected from 5 individuals from the same family. Gender, age, tooth position (anterior/posterior) and tooth type (deciduous/permanent) were recorded for each patient. Following collection, teeth were placed in 0.1% thymol solution until Micro-CT scan. Projection images were reconstructed and analyzed. On study 3, unstimulated whole and stimulated parotid saliva were obtained from 8 individuals with (AFF) and 8 healthy individuals, both genders, without (CON) x-linked hypophosphatemic rickets aged from 8 to 66 years. Supernatants were analyzed by high performance liquid chromatography, and the salivary flow rate (ml/min) was calculated. Each major peak in the HPLC chromatogram of each sample was characterized. On study 4, unstimulated whole and stimulated parotid saliva were also obtained, being total protein concentration determined by the Bicinchoninic Acid Protein (BCA) method. Proteins were characterized according to their molecular weights within the unidimensional electrophoresis. The study 1 showed the importance of the knowledge of clinical signs and symptoms of XLHR for the correct diagnosis of this disease, and for the establishment of preventive and comprehensive dental care. On article 2, teeth of all affected patients presented dentin with a different mineralization pattern compared to the teeth of the healthy individual with dentin defects observed next to the pulp chambers. On the third article, whole and parotid salivary flows were significantly different (p = 0.001), being flow of whole saliva higher (0.518  0.282 mL/min) than parotid saliva (0.124  0.086 mL/min). Whole salivary flow rate was higher in the AFF group (0.698  0.229) than in the CON group (0.339  0.210 mL/min) (p = 0.006). Twenty-eight peaks were found in whole and 21 peaks in parotid saliva. Whole saliva of the CON group presented lower number of peaks than AFF group. In parotid saliva, peaks 17 and 28 (retention times: 24 and 39 min) were found exclusively in the AFF group, and peak 13 (retention time: 19 min) exclusively in the CON. Article 4 showed difference concerning to total protein concentration between whole and parotid saliva (p < 0.001), being higher concentration found in whole saliva (102.603  42.336 Âg/mL) than in parotid saliva (0.699  0.438 Âg/mL). Bands with 102 kDa, 48 kDa and 24 kDa presented higher intensity in whole saliva of CON group (p = 0.015, p = 0.043 and p = 0.022). In conclusion, XLHR patients presented specific characteristics in dentin mineralization and salivary proteins and peptides, which can lead to differentiate these patients from healthy individuals, improving the diagnostic field. / Raquitismo hipofosfatÃmico ligado ao cromossomo X (XLHR) à a maior causa de raquitismo hereditÃrio, com uma incidÃncia de 1:20.000 nascidos vivos, representando mais de 80% das formas de raquitismo hipofosfatÃmico familiar. A saliva à o fluido humano mais disponÃvel e de fÃcil acesso, o que faz dela uma das ferramentas mais pesquisadas no diagnÃstico de patologias. Nesse contexto, essa tese, constituÃda de 4 artigos objetivou: (1) descrever as principais manifestaÃÃes sistÃmicas, achados orais e tratamentos dentÃrios em 3 geraÃÃes de uma famÃlia afetada; (2) analisar o padrÃo de mineralizaÃÃo do esmalte e da dentina nos pacientes afetados por XLHR, utilizando microtomografia computadorizada (Micro CT), e associar a mineralizaÃÃo do esmalte e da dentina em dentes decÃduos e permanentes, segundo gÃnero e presenÃa/ausÃncia da doenÃa; (3) avaliar o perfil de peptÃdeos na saliva de pacientes com XLHR, utilizando cromatografia lÃquida de alta performance (HPLC); e (4) caracterizar proteÃnas salivares nessa condiÃÃo, utilizando eletroforese unidimensional. No estudo 1, exames orais, laboratoriais e avaliaÃÃes histolÃgicas, tomografias computadorizadas cone-beam e radiografias periapicais foram realizadas para a apropriada instituiÃÃo da estratÃgia de tratamento mais adequada. No estudo 2, dentes foram coletados de 5 indivÃduos de uma mesma famÃlia. GÃnero, idade, posiÃÃo dentÃria (anterior/posterior) e tipo dentÃrio (decÃduo/permanente) foram registrados para cada paciente. ApÃs a coleta, os dentes foram colocados em soluÃÃo de timol a 0,1% atà a anÃlise atravÃs do Micro CT. As imagens projetadas foram reconstruÃdas e analisadas. No estudo 3, saliva total nÃo estimulada e saliva de parÃtida estimulada foram obtidas de 8 indivÃduos afetados com (AFF) e 8 indivÃduos sem (CON) XLHR, de ambos os gÃneros e idades entre 8 e 66 anos. Sobrenadantes foram analisados por meio de HPLC e o fluxo salivar (mL/min) foi calculado. Os picos que se apresentaram maiores nos cromatogramas do HPLC foram caracterizados. No estudo 4, saliva total nÃo estimulada e saliva de parÃtida estimulada tambÃm foram obtidas, sendo a concentraÃÃo de proteÃnas totais determinada pelo MÃtodo do Ãcido BicinconÃnico (BCA). ProteÃnas foram caracterizadas de acordo com o peso molecular atravÃs de eletroforese unidimensional. O estudo 1 mostrou a importÃncia do conhecimento dos sinais e sintomas clÃnicos do XLHR para o correto diagnÃstico dessa doenÃa, e para o estabelecimento de atendimento odontolÃgico preventivo e abrangente. No artigo 2, os dentes de todos os pacientes afetados apresentaram dentina com padrÃo de mineralizaÃÃo diferente comparado aos dentes de indivÃduos saudÃveis, sendo os defeitos na dentina observados prÃximo Ãs cÃmaras pulpares. No artigo 3, os fluxos salivares da saliva total e de parÃtida foram significativamente diferentes (p=0,001), sendo o fluxo de saliva total maior (0,518  0,282 mL/min) do que o de saliva de parÃtida (0,124  0,086 mL/min). O fluxo salivar da saliva total foi maior no grupo AFF (0,698  0,229) que no grupo CON (0,339  0,210 mL/min) (p = 0,006). Vinte e oito picos foram encontrados em saliva total e 21 em saliva de parÃtida. A saliva total do grupo CON apresentou menor nÃmero de picos que a do grupo AFF. Na saliva de parÃtida, os picos 17 e 28 (tempos de retenÃÃo: 24 e 39 min) foram encontrados exclusivamente no grupo AFF e o pico 13 (tempo de retenÃÃo: 19 min) no CON. Artigo 4 demonstrou diferenÃa relacionada à concentraÃÃo de proteÃnas totais entre saliva total e de parÃtida (p < 0,001), sendo a maior concentraÃÃo encontrada na saliva total (102,603  42,336 Âg/mL) que na saliva de parÃtida (0,699  0,438 Âg/mL). Bandas com 102 kDa, 48 kDa e 24 kDa apresentaram maior intensidade na saliva total do grupo CON (p = 0,015, p = 0,043 e p = 0,022). Em conclusÃo, pacientes com XLHR apresentaram caracterÃsticas especÃficas relacionadas à mineralizaÃÃo dentinÃria e proteÃnas e peptÃdeos salivares que podem levar à diferenciaÃÃo desses pacientes de indivÃduos saudÃveis, avanÃando no campo diagnÃstico.

A ocorrência de fraturas em animais e, especialmente nas espécies de grande porte, geram preocupação quanto ao custo do tratamento e a ocorrência de sequelas, pois há a possibilidade de complicações pela carga excessiva que esses animais exercem sobre os membros. Dessa forma é importante a imobilização imediata do membro e de maneira adequada, e avaliar se há necessidade de se realizar cirurgia para estabilização da fratura. Em algumas fraturas pode haver falhas ósseas, principalmente em fraturas cominutivas com extensa lesão de tecidos adjacentes, o que dificulta e prolonga o tempo de consolidação. Por essas razões vem sendo estudado, há alguns anos, o uso de substitutos ósseos na forma de cimentos ou mantas ósseas para reparar esses defeitos. O estudo com biomateriais como substitutos ósseos tem tido grande evolução nos últimos anos, e aqueles à base de quitosana, hidroxiapatita e colágeno apresentam grande vantagem, pois a quitosana estimula a regeneração óssea, a hidroxiapatita confere a dureza que o material exige, e o colágeno fornece maleabilidade. O presente projeto teve por objetivo avaliar o reparo ósseo após implante de compósito à base de quitosana, hidroxiapatita e colágeno, em falhas ósseas de tíbias de ovinos induzidas experimentalmente. Foram utilizados os métodos de imagem por densitometria ótica radiográfica e microtomografia computadorizada 3D para avaliar o grau e o tempo de reparo ósseo, assim como a densidade mineral óssea durante a cicatrização. As falhas ósseas foram confeccionadas nas tíbias de ovelhas, em ambos os membros, onde foi implantado o biomaterial em um deles, e o membro contralateral mantido como controle. Posteriormente, os animais foram submetidos a exames radiográficos, quinzenalmente, até 90 dias de pós operatório. Após este período, os animais foram submetidos à eutanásia e fragmentos das tíbias foram colhidos para avaliação por microtomografia computadorizada 3D. Observou-se, pelos resultados qualitativos das imagens radiográficas e dos dados estatísticos, que houve absorção gradativa do biomaterial, e que não houve diferença estatística em relação à densidade mineral óssea entre os dois grupos estudados, embora a DMO tenha sido maior nos membros com o biomaterial. Este método mostrou-se prático e eficaz, além de ser uma técnica não invasiva. A microtomografia computadorizada 3D revelou importantes informações quanto à porosidade óssea e volume ósseo entre os dois grupos. As imagens em 3D mostraram detalhes do osso que não eram possíveis de visualizar por meio das radiografias. Dessa forma é uma técnica bastante eficaz e detalhada, mas é necessária padronização de todas as amostras para poder quantificar os valores adequadamente. O estudo estatístico não mostrou diferenças entre os grupos com biomaterial e controle para os parâmetros de volume ósseo, grau de porosidade e porcentagem de volume ósseo. Porém, pelas imagens em 3D observa-se nitidamente maior quantidade de poros nas amostras controle em relação às amostras com biomaterial. Conclui-se com este estudo que as técnicas de densitometria óssea por raios-X e &micro;CT 3D são bastante eficazes para avaliar a cicatrização óssea em ovinos / The occurrence of fractures in animals and, especially, in large animals are conditions that generate concern about the cost of treatment and the occurrence of future complications because there is the possibility of complications due to excessive load that these animals receive in their limbs. Thus, it is important the limb immobilization immediately and appropriately and assess whether it is necessary to perform surgery to stabilize the fracture. In some kinds of fractures, it might have large bone defects, mainly in comminuted fractures with extensive damage to surrounding tissue, which makes it more difficult and prolongs the consolidation time. For these reasons, scientists have been studied the use of bone substitutes in the form of bone cements to repair these defects. The study of biomaterials as bone substitutes has had great progress in last years, and those based on chitosan, hydroxyapatite and collagen had great advantage because chitosan stimulates bone regeneration, hydroxyapatite confers the hardness that the material requires, and collagen provides flexibility to the material. This project aims to assess bone repair after deploying a composite of chitosan, collagen and hydroxyapatite in bone defects experimentally induced in sheep tibiae. For assessing the degree and the time of bone healing, it was used imaging techniques like radiographic bone densitometry and 3D micro-computed tomography. Bone defects were made in the sheep tibiae in both limbs where the biomaterial was deployed in one of them, and the control was the contralateral limb. After the surgeries, the animals were submitted to radiographic exams every two weeks until 90 days postoperatively. After this period, the animals were euthanized and harvested tibiae fragments for evaluation by 3D micro-computed tomography. Through the qualitative results of images and statistical data, it was observed, radiographically, that there was a gradual absorption of the biomaterial, and also that there was no statistical difference in relation to bone mineral density between the two groups. The method of determining the X-ray BMD proved to be practical and effective, and it is a noninvasive technique. 3D micro-computed tomography revealed important information about bone porosity and bone volume between the two groups. The 3D images showed bone details that were not possible to visualize through radiographs. Thus it is a highly effective and detailed technique, but it requires patterning of all the samples in order to quantify the amounts properly. Statistical analysis showed no differences between the groups for bone volume parameters, degree of porosity and percentage of bone volume. However in the 3D images, it can be observed clearly larger amount of pores in the control samples in comparison to those with biomaterial. It is concluded from this study that the techniques of bone densitometry X-ray and 3D &micro;CT are very effective to evaluate bone healing in sheep. Bone mineral density was higher in limbs with biomaterial and there was a higher bone volume and lower degree of porosity in the samples with biomaterial compared to the control group

The use of lime for soil stabilization has greatly increased since the second half of the 20th century. A lot of research has been conducted to understand the mechanisms of stabilization. These mechanisms are caused by pozzolanic reactions between lime and clay minerals. However, it has not yet been possible to quantify the factors affecting the evolution of these reactions. The variety of soils and the disruptive elements do not allow comparing these soils with each other and giving any quantitative and generalized conclusions in terms of mechanical improvement. The goal of this study is to build a progressive understanding of this phenomenon by avoiding any disruptive elements and controlling most of the parameters. Consequently, the choice is made to study a synthetic soil by controlling its particle size distribution and composition. This soil is a mixture of sand and bentonite taken at different compositions. An analysis of the evolution of lime treatment on such model soils is carried out on two scales: the macroscopic scale and the microscopic scale. The macroscopic scale studies the evolution through unconfined compressive strength, lime consumption, electrical resistivity as well as complementary studies such as sonic and triaxial tests. Results from macroscopic tests show that sand takes an important part into soil stabilization, meaning that a soil containing a lot of clay does not necessary give the best long term mechanical characteristics. Tests that allow a much more detailed comprehension of stabilization are also presented. Microscopic evolution is studied through X-Ray Computed Tomography and Mercury Intrusion Porosimetry. A study on tomographic image treatment has also been carried out to segment the images from its different constituents. / L'utilisation de la chaux pour stabiliser le sol s'est considérablement déve-lop-pée depuis la seconde moitié du 20e siècle. De nombreuses recherches ont vu le jour pour comprendre les mécanis-mes de cette stabilisation. Ces mé-ca-nis-mes sont causés par les réactions pouzzolaniques entre la chaux et les minéraux argileux. Cependant, il n'a pas encore été possible de quantifier totalement les facteurs influençant le déroulement de ces réactions. La diversité des sols et la présence d'éléments perturbateurs ne permettent pas de les comparer et d'en tirer des conclusions quantitatives et généralisables en termes d'amélioration des paramètres mécaniques. Cette étude envisage donc de construire une compréhension progressive du phénomène en ne prenant pas en compte les éléments perturbateurs et en contrôlant à priori un maximum de paramètres. Pour ce faire, il est proposé d'étudier un sol synthétique dont la granulométrie et la composition peuvent être contrôlées. Ce sol est un mélange de sable et de bentonite pris à différentes compositions. Une analyse sur l'évolution du traitement à la chaux est alors effectuée sur ces mélanges sur deux échelles :l'échelle macroscopique et l'échelle microscopique. L'échelle macroscopique envisage des essais de compression simple, de consommation de chaux, de résistivité électrique ainsi que des essais complémentaires tels que les essais soniques et triaxiaux. Les résultats macroscopiques montrent que le sable joue un rôle important dans la stabilisation, le sol présentant la fraction argileuse la plus importante n'ayant pas les meilleures caractéristiques mécaniques à long terme. Les tests permettant une compréhension plus fine de cette stabilisation sont également présentés. L'échelle microscopique est étudiée via la tomographie aux rayons-X et la porosimétrie au mercure. Une étude sur le traitement des images tomographiques est aussi mise en oeuvre pour segmenter de manière adéquate les images de ses différents constituants. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

The Ottawa Embayment is a intracratonic rift basin that preserves a unique and eventful history through deep time. Its evolution records opening of the Iapetus Ocean with the break-up of Rodinia, followed by the formation of a continental passive margin, trapping siliciclastic sediments eroded from the adjacent Grenville Province. Samples were collected from a transect across the crystalline rift flank and through the embayment. We investigate the influence of crystallinitiy and non-ideal crystal chapes on He diffusion and resulting zircon (U-Th)/He age with the use of zircon (U-Th)/He thermochronometry, raman spectroscopy and x-ray micro-computed tomography. We then integrate our thermochronology data with regional geology to utilize multi-sample numerical modelling to improve our understanding of the thermal history of the Ottawa Embayment and the evolution of intracratonic rift basins. The works collected within define a comprehensive temperature-time history for the basin and rift flank from the Late-Mesoproterozoic to present day.

Introdução: Os objetivos deste estudo foram comparar a extrusão apical de debris durante a desobturação com WaveOne Gold, ProTaper retratamento, D-RaCe ou limas manuais; descrever as falhas e/ou fraturas ocorridas nos instrumentos de NiTi; e comparar o WaveOne Gold com os sistemas ProTaper e RaCe em relação à quantidade de material obturador remanescente, transporte apical (TA) e tempo de trabalho após a desobturação e após o repreparo de canais radiculares curvos. Materiais e Métodos: Quarenta canais mésiovestibulares de molares superiores foram preparados, obturados e divididos em 4 grupos (n=10): WOG) WaveOne Gold Primary e Medium; PTG) ProTaper Retreatmento e ProTaper Next; RCG) D-RaCe e RaCe; e LM) Limas manuais. A extrusão de debris foi determinada subtraindo-se o peso final do peso inicial dos Eppendorfs. Os instrumentos de NiTi (n=18) foram analisados em MEV antes e após a desobturação. A quantidade de material obturador remanescente e o TA foram avaliados em micro-TC. O tempo de trabalho foi anotado e comparado. Os dados foram estatisticamente analisados (α=.05). Resultados: WOG extruiu menos debris do que LM e RCG (P<.05), e foi similar ao PTG (P>.05). Não houve diferença entre LM, PTG e RCG (P>.05). A análise em MEV mostrou, dos 18 instrumentos avaliados, 3 fraturas e 10 deformações. Nas duas etapas avaliadas, WOG apresentou similar (P>.05) e menor (P<.05) quantidade de material obturador remanescente do que PTG e RCG, respectivamente. A quantidade de material no WOG e RCG foi menor após o repreparo (P<.05). Na desobturação, WOG teve maior TA em 4mm do que em 2mm (P<.05). Em 2mm, o TA do WOG foi menor do que RCG (P<.05), e em 4mm foi igual ao PTG e RCG (P>.05). Na desobturação, o tempo de trabalho no grupo LM foi maior que nos demais (P<.05). No repreparo, WOG foi mais rápido do que PTG e RCG (P<.05). Conclusões: Todos os instrumentos causaram extrusão de debris, sendo que o WOG apresentou os menores valores. Nenhum sistema removeu completamente o material obturador de raízes mésiovestibulares de molares superiores. Considerando os baixos valores de TA obtidos, os instrumentos avaliados foram considerados seguros para desobturação e repreparo de canais curvos. A desobturação com LM foi mais lenta do que com os instrumentos de NiTi. O sistema reciprocante foi mais rápido do que os rotatórios no reprepro. / Introduction: The aims of this study were to assess the amount of apically extruded debris during filling removal with WaveOne Gold, ProTaper Retreatment, D-RaCe or hand files; to describe failures of NiTi instruments; and to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT) and working time after filling removal and after shaping of curved root canals. Methods: Forty mesiobuccal canals of maxillary molars were prepared, filled, and assigned into 4 groups (n=10): WOG) WaveOne Gold Primary and Medium; PTG) ProTaper Retreatment and ProTaper Next; RCG) D-RaCe and RaCe; HF) Hand files. The amount of extruded debris was determined by subtracting the final from the initial Eppendorfs weight. The NiTi instruments (n=18) used for filling removal were analyzed pre and post-operatively by SEM. Micro-CT analysis assessed the residual filling material and AT. Working time was recorded and compared. Data were statistically analyzed (α=.05). Results: WOG produced less debris compared with HF and RCG (P<.05), and similar to PTG (P>.05). HF, PTG and RCG showed no difference (P>.05). SEM analyses after filling removal showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. In both evaluated steps, WOG had similar (P>.05) and less (P<.05) amount of filling material as PTG and RCG, respectively. The remaining material in WOG and RCG was lower after shaping (P<.05). In filling removal, WOG had higher AT at 4mm than at 2mm (P<.05). At 2mm, AT of WOG was lower than RCG (P<.05), and at 4mm, was equal to PTG and RCG (P>.05). In filling removal, working time in HF group was significantly higher than others (P<.05). In shaping step WOG was faster than PTG and RCG (P<.05). Conclusions: All instruments tested caused debris extrusion, with WOG presenting the lowest values. Neither system could completely remove the filling material of mesiobuccal canals of maxillary molars. Considering the low AT values obtained, the instruments evaluated were safe for filling removal and shaping of curved canals. Filling removal with HF was slower than with the NiTi files. The reciprocating system was faster than the rotary in shaping the root canals.

No description available.

No description available.

BACKGROUND: The ultrasonic vibrations from the piezoelectric knife may amplify the natural response to surgical injury. This may lead to different clinical and biological outcomes when using the piezoelectric knife versus a surgical bur to create selective cortical penetrations for alveolar ridge augmentation surgeries. The first aim of this study was to analyze the differences in bone graft healing when selective cortical penetrations are created with a surgical bur and with a piezoelectric knife. The second aim of this pilot study was to see if enhanced new bone formation during bone regeneration procedures can be achieved with the use of a piezoelectric knife versus the conventional bur or onlay grafting techniques utilizing deep learning, a subset of machine learning. MATERIALS & METHODS: he project was approved by the Boston University Medical Center Institutional Animal Care and Use Committee (IACUC). Twenty, 9-10 week male Sprague Dawley rats, weighing approximately 300g, were used in this study. The rats were randomly divided into three groups: Xenograft, Alloplast, and Collagen. These groups were further divided by surgical technique: Bur, Piezo, and Onlay. For the Bur and Piezo groups, four equally-spaced selective cortical penetrations were made prior to bone graft stabilization. Three rats served as controls (Control group). Microcomputed tomography scans (µCT) were acquired for each sample, containing approximately 1,000 slices of data each. After 28 days of healing the volumes of and density of the newly formed bone were extracted and analyzed for each group. This was achieved with an innovative deep learning algorithm designed for multi-level segmentation and regional feature detection utilizing convolutional neural networks (CNN). RESULTS: Microcomputed tomography (µCT) of our samples yielded very localized, high-resolution scans of our surgical samples. The innovative deep learning algorithm was able to reliably produce highly accurate, unbiased segmentations of our samples. This study demonstrated that new bone formation was possible with all nine of the tested surgical techniques, however the differences were not statistically significant. Selective cortical penetrations with a piezoelectric knife (PIEZO) resulted in significantly more “cortical-like” new bone formation at 28 days. CONCLUSION: Within the limitations of this preliminary study, it is possible to conclude that the piezoelectric knife is a valid alternative to conventional carbide burs when making selective cortical penetrations prior to bone grafting surgery. Additionally, our deep learning algorithm successfully segmented thousands of slices of data and allowed for the calculation of porosity and new bone volume in our samples.