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Objetivo:Avaliar a longevidade de restaurações adesivas diretas em dentes decíduos submetidos à remoção parcial de tecido cariado (RPTC) e os possíveis fatores associados com o insucesso, tentando aproximar os resultados à vida clínica diária. Métodos: Estudo observacional analítico retrospectivo que incluiu 284 restaurações adesivas diretas em dentes decíduos posteriores e anteriores confeccionadas após RPTC em 88 crianças com alta experiência de cárie. Os dentes foram acompanhados clínica e radiograficamente através da informação registrada nos prontuários clínicos dos pacientes. Adicionalmente, foram investigados os fatores potencialmente associados com o insucesso do tratamento, tais como idade, gênero, tipo de dente, número de faces restauradas, material capeador e restaurador utilizado e índice de placa visível (IPV) e de sangramento gengival (ISG). O estimador Kaplan-Meiere o teste de Log-Rank foram utilizados para analisar a longevidade das restaurações e o modelo de regressão multivariado de Cox com fragilidade compartilhada, para avaliar os fatores que poderiam estar relacionados com a falha do tratamento (p<0,05). Resultados: A taxa de sucesso clínico e radiográfico da amostra foi de 76% e obteve-se uma taxa de falha anual (AFR) de 20% na análise até 36 meses. O IPV (p=0,014) e o tipo de dente, anterior ou posterior (p<0,001) mostraram influência significativa no insucesso das restaurações. Conclusão: restaurações adesivas realizadas após RPTC na dentição decíduae em um ambiente que simula a vida clínica diária demonstrambons resultados, principalmente em dentes posteriores. Porém, o acúmulo de biofilme sobre as superfícies dentárias afeta a longevidade das mesmas. / Objective: to assess the longevity of direct adhesive restorations undergoing partial caries removal (PCR) in primary teeth and associated factors for failure, approaching the results to a daily clinical life. Methods: Retrospective analytical observational study which included 284 posterior and anterior primary teeth direct adhesive restorations that had been treated with PCR of 88 children with high caries experience. The teeth had clinical and radiographic follow-up through the information registered in the clinical records of the patients.In addition, factors potentially associated with treatment failure were investigated, such as age, gender, type of tooth involved, number of surfaces restored, type of capping material and restorative material used, visible plaque (VPI) and gingival bleeding indexes (GBI). Kaplan-Meier estimate and Log-Rank test were used to analyze the longevity of restorations and multivariate Cox´s regression model with shared frailty to evaluate the factors that could be related to treatment failure (p<0.05). Results: A clinical and radiographic success rate of the sample was 76% and an annual failure rate was estimated in 20% over 36 months. Only visible plaque index (p=0.014) and type of teeth, anterior or posterior (p<0.001) had a significant influence on the restorative failure. Conclusion:Adhesive restorations undergoing PCR in primary teeth in an environment that simulates a daily clinical life demonstrate good results, particularly in posterior teeth. However, the biofilm accumulation on the dental surfaces affects the longevity of them.

Indiana University-Purdue University Indianapolis (IUPUI) / Provisional restorative treatment is an essential part of fixed prosthodontics. Incorporation of adequately constructed provisional restorations will enhance the success rate of definitive restorations. Repairing or replacing failed provisional restorations is a concern for both clinicians and patients. The objective of this investigation was to study the effects of alumina nanofibers reinforcement on the mechanical properties of commercially available provisional fixed partial denture PMMA material. The hypothesis was that the addition of alumina nanofibers to commercially available PMMA resin will significantly increase its flexural strength, fracture toughness, and microhardness. Alumina nanofibers at 0.0 wt %, 0.5 wt %, 1.0 wt %, and 2.5 wt % were added to commercially available provisional fixed partial material (Jet Tooth Shade). A quaternary ammonium acetate dispersant (CC-59, Goldschmidt, Janesville, WI) was added to the acrylic monomer at 0.0 wt %, 1.0 wt %, 2.0 wt % and 5.0 wt % of the nanofiber weight (12 test groups, 1 control). Samples from each group were evaluated for flexural strength, flexural modulus, fracture toughness, and microhardness. The samples were tested after storing in distilled water for 24 hours and 7 days at 37ºC. Two-way analysis of variance (ANOVA) was used to test the effects of storage time and combinations of alumina nanofiber level and quaternary ammonium acetate dispersant level on the flexural strength, fracture toughness, and microhardness of the provisional PMMA resin. Pair-wise comparisons between groups were performed using Tukey’s multiple comparisons procedure to control the overall significance level at 5 percent. Three fracture toughness samples/group were randomly selected for Energy Dispersive Spectrometry (EDS) to qualitatively evaluate the dispersion of the fibers. The data obtained from this study showed that control sample values were in the acceptance range compared with previous research. The experimental samples did not reinforce the provisional resin in the flexural strength, modulus, fracture toughness, or microhardness. There are several factors may attribute to these results, such as poor bonding at the filler/matrix interface. The more homogeneous the mixture of PMMA and fiber, the stronger the acrylic resin. In fact, the presence of poorly bonded fibers, to which little load is transferred, can be almost equivalent to voids. In addition, as seen with EDS images, alumina nanofibers had a tendency to agglomerate. The use of a magnetic stirrer was not effective in physically separating nanofibers agglomerates. Direct dispersion of alumina nanofibers in methyl methacrylate monomer and quaternary ammonium acetate dispersant was not effective in separating the nanofibers into nano-scaled single crystals. The presence of fiber agglomerates acts as a structural defect that detrimentally affects the mechanical properties. Further studies are needed to evaluate the effectiveness of fibers, dispersion techniques, and coupling agents to enhance the mechanical properties of the provisional PMMA resin.

La dynamique des courants de turbidité est fortement contrôlée par la morphologie du fond marin. Les turbidites issues de ces courants constituent des réservoirs d’hydrocarbures très importants dans les bassins sédimentaires à travers le monde. L'objectif principal de ce travail est de comprendre comment le paleorelief a contrôlé la géométrie et l'architecture des réservoirs turbiditiques, en utilisant comme zone d'étude les réservoirs du Crétacé d'un champ pétrolier du bassin de Campos (offshore du Brésil), où la tectonique a été en partie dominée par l'halocinèse. La méthodologie utilisée dans cette thèse a couplé deux approches. La première a inclus à la fois la description des séquences sédimentaires, à partir de données de sismique-réflexion et de puits, et les restaurations structurales. Six horizons régionaux et quatre unités-réservoirs ont été identifiés et cartographiés afin de construire un modèle géologique multi-2D. Ces surfaces ont ensuite été aussi restaurées. Les résultats de cette étape suggèrent que les failles liées à l'halocinèse ont contraint la paléotopographie pour le dépôt des réservoirs plus anciens et que des structures tectoniques et un canyon ont formés les contraintes paléotopographiques pour la distribution des réservoirs plus jeunes. La seconde approche a été l'analyse du rôle des paramètres des écoulements en effectuant des simulations numériques du type stratigraphique (Dionisos) et des automates cellulaires (CATS). Une surface restaurée, considérée comme référence pour le dépôt des unités-réservoirs a été utilisée comme paléotopographie pour les simulations CATS. Le modèle numérique a été contraint par les données réservoirs. Cette utilisation inédite des simulations 3D avec des automates cellulaires dans une étude de cas réel concernant des dépôts marins anciens a produit des résultats réalistes par rapport aux exemples modernes connus. Elle a également fourni des résultats plus exploitables à l'échelle de réservoir que les modèles numériques de type "stratigraphique". Ce travail met en évidence l'importance des interactions tectonique-sédimentation et de la paléotopographie pour la distribution de réservoirs turbiditiques. / The dynamic of gravity-driven turbidity currents is strongly influenced by the morphology of the seafloor. The resulting turbidites constitute important hydrocarbon reservoirs in sedimentary basins throughout the world. The main objective of the present work is thus to understand the way the paleorelief controls turbidite reservoir architectures, with application in a specific study area with Cretaceous reservoirs in Campos Basin (Brazilian offshore). The tectonics in this Basin was partly controlled by halokinesis. The first approach was describing the local Cretaceous sedimentary sequence architecture, from seismic and well data, and performing structural restorations. Six regional horizons and four reservoir-scale units were identified and mapped in order to build a multi-2D geological model. Structural restorations highlighted the structural evolution and allowed the related horizon palaeotopography to be obtained. The results of this work step suggest that the halokinesis-related listric faults regulated the distribution of the basal reservoirs. Moreover, at the top of the Albian carbonates, a canyon was identified, which, in association with the tectonic structures, forms the palaeotopographic constraints for the upper reservoir geometry. The second approach was analyzing the role of flow controlling parameters by performing stratigraphic (Dionisos) and cellular automata-based (CATS) numerical simulations. The latter provided a more appropriate reservoir scale-simulation process than Dionisos. A restored surface, considered as reference for the deposition of the reservoir units, was used as the palaeotopography for CATS simulations, having as constraints the reservoir data. This pioneer use of cellular automata simulations in a real subsurface case study produced coherent results when compared with the actual reservoir distribution. This work sheds light on the importance of tectonic-sedimentation interactions and of palaeotopography for the distribution of turbidite reservoirs.