O objetivo deste trabalho foi avaliar as alterações dimensionais de resinas acrílicas submetidas a diferentes tipos de processamento avaliados ao nível condilar. As condições experimentais foram introduzidas em três etapas. Na etapa A, as resinas acrílicas (Clássico, Ondacryl, Acron MC, Lucitone e QC-20) foram incluídas em muflas contendo muralha de gesso, prensadas na fase plástica e submetidas a cinco ciclos de acrilização. Na etapa B, as resinas acrílicas utilizadas foram a QC-20 e a Lucitone, utilizando três tipos de muralha (gesso, silicone (ZETALABOR) e filme de silicone (VIPISIL)), e duas fases de reação química da resina acrílica na prensagem (fluida e plástica). Na etapa C, foi utilizada a resina Acron MC com dois ciclos de polimerização (90W por treze minutos e 500W por três minutos) variando-se, ainda, o tipo de muralha como na etapa B. Para o estudo, foram confeccionadas 5 próteses totais para cada grupo. Ao final, obtiveram-se 23 grupos totalizando 115 próteses totais superiores. Mediu-se a variação posicional do ramo superior do articulador TT antes e após os processamentos, tendo por base a orientação oclusal da máxima intercuspidação. Tal variação foi registrada através de gesso tipo IV vertido em espaço ao redor das esferas condilares, previamente providos por meio de espaçadores utilizados antes do processamento. Foram medidas três distâncias em cada esfera condilar (superoinferior, anteroposterior e mediolateral) resultando em 690 medidas que variaram de 0 a 3 mm, com média de 0,79 mm e desvio padrão de 0,59 mm. Ocorreu alteração em 687 medidas, sendo que houve diferença entre os grupos, estatisticamente significante, principalmente para a distância anteroposterior do lado esquerdo, na variável resina. Conclui-se que, as alterações dimensionais de resinas alteraram as posições das esferas condilares. / The objective of this study is to evaluate the dimensional acrylic resin alterations submitted to different types of processing evaluated to the level of the condyle. The experimental conditions were introduced in three stages. In stage A , the acrylic resins (Classic, Ondacryl, Acron MC, Lucitone and QC-20) were enclosed in flasks contend plaster wall, pressed in the plastic phase and submitted to five cycles of acrylization. In stage B, the QC-20 and the Lucitone were used with three types of wall (plaster, silicone (ZETALABOR) and silicone film (VIPISIL)), and with two phases of chemical reaction of the acrylic resin (fluid and plastic). In stage C, the resin Acron MC with two cycles of polymerization was used (90W for thirteen minutes and 500W for three minutes) by changing the type of wall as in stage B. For the study, 5 complete dentures for each group were made. At the end of the experiment, 23 groups were obtained, totalizing 115 superior complete dentures. Positional variation of the upper member of the articulator T.T.was measured before and after the processing, based on the maximum intercuspidation orientation. Such variation was registered by using plaster type IV shed in the space around of the condyle spheres, previously provided by means of spacers used before the processing. Three distances in each condyle sphere were measured (superoinferior, anteroposterior and mediolateral) resulting in 690 measures that varied from 0 to 3 mm, with average of 0,79 mm and shunting line standard of 0,59 mm. An alteration in 687 measures occurred and there was difference between the groups statistically significant, mainly for the anteroposterior distance on the left side. The conclusion was that the dimensional resin alterations modified the positions of the condyle spheres

Submitted by Edineia Teixeira (edineia.teixeira@unioeste.br) on 2018-10-03T19:48:30Z No. of bitstreams: 2 Patricia_Macedo2018.pdf: 792975 bytes, checksum: a12fcccb5877a843f32aabd7aa561149 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-10-03T19:48:30Z (GMT). No. of bitstreams: 2 Patricia_Macedo2018.pdf: 792975 bytes, checksum: a12fcccb5877a843f32aabd7aa561149 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-26 / The purpose of this study was to evaluate, in vitro, the effect of ozonated water as a cleaning solution on the bond strength of glass fiber pins. Ninety-eight bovine roots were used, divided randomly into 7 groups, according to the irrigation and dentin cleaning solution: HP/HP – 2,5% sodium hypochlorite, AD/AD - distilled water;; CHX/CHX - 2% chlorhexidine; AO/AO - ozonated water 4 ppm; HP / AD – 2,5% sodium hypochlorite and distilled water; HP / CHX - 2.5% sodium hypochlorite and 2% chlorhexidine and, HP / AO – 2,5% sodium hypochlorite and 4 ppm ozonated water. The root canals were prepared endodontically according to the irrigating solutions of each group and stored in distilled water. After 7 days, they were cleared and cleaned according to cleaning solutions. The fiberglass pins were cemented using self-adhesive cement. After 7 days of cementation, the roots were sectioned (6 discs each) and submitted to the push-out test. The analysis of the type of fracture was done with a stereoscopic magnifying glass of 4,5x. Data were analyzed statistically by ANOVA and Tukey tests with a significance level of 5%. The highest mean of push-out union strength in the cervical third was obtained in the AO (11,67), HP (11,21) and HP / AO (9,71) groups, maintaining this same tendency in the middle and apical thirds. The AO and HP were the most relevant solutions in the treatment of root dentin. / O propósito deste estudo foi avaliar, in vitro, o efeito da água ozonizada como solução de limpeza sobre a resistência de união de pinos de fibra de vidro. Foram utilizadas 98 raízes bovinas n = (14), divididas aleatoriamente em 7 grupos, de acordo com a solução irrigadora e de limpeza dentinária: HP/HP - hipoclorito de sódio 2,5%; AD/AD - água destilada; CHX/CHX - clorexidina 2%; AO/AO - água ozonizada 4 ppm; HP/AD - hipoclorito de sódio 2,5% e água destilada; HP/CHX - hipoclorito de sódio 2,5% e clorexidina 2%, e HP/AO - hipoclorito de sódio 2,5% e água ozonizada 4 ppm. Os canais radiculares foram preparados endodonticamente de acordo com as soluções irrigadoras de cada grupo e armazenados em água destilada. Após 7 dias, foram desobturados e limpos de acordo com as soluções de limpeza. Os pinos de fibra de vidro foram cimentados, utilizando cimento resinoso autoadesivo. Após 7 dias da cimentação, as raízes foram seccionadas (6 discos cada) e submetidas ao teste de push-out. A análise do tipo de fratura foi feita com uma lupa estereoscópica de 4,5x. Os dados obtidos foram analisados estatisticamente pelos testes ANOVA e Tukey com nível de significância 5%. A maior média de resistência de união push-out no terço cervical foi obtida nos grupos AO (11,67), HP (11,21) e HP/AO (9,71), mantendo esta mesma tendência nos terços médio e apical. A AO e HP foram as soluções mais relevantes no tratamento da dentina radicular.

A força de adesão entre resinas e ligas de metais básicos resulta do embricamento mecânico entre a superfície do metal e a resina e da interação química entre óxidos presentes na superfície dos metais e monômeros adesivos das resinas compostas. A literatura, entretanto, mostra que ainda persistem algumas dúvidas sobre a interação entre os diversos tipos de sistemas adesivos e metais básicos, por isso, essa pesquisa visa: verificar se a presença do Be na composição de ligas a base de Ni-Cr influencia a união metal básico/resina; comparar dois cimentos resinosos adesivos nessa função e verificar a influência da utilização de condicionadores (primers) adesivos metálicos para ligas nobres sobre essa união. Após 2500 termociclos, foram realizados testes de resistência à tração em 160 corpos-de-prova, que consistiam de dois discos de Ni-Cr-Be (Verabond – Aalba Dental Inc., Cordelia, CA-USA) com 6 mm de diâmetro e 2 mm de espessura cimentados entre si, e dois discos de Ni-Cr (Durabond - Odonto Comercial Importadora Ltda, São Paulo, SP), com as mesmas dimensões, cimentados entre si. Foram utilizadas diferentes marcas comerciais de sistemas adesivos: os cimentos resinosos adesivos, Panavia F (Kuraray Co. Ltd.), Bistite II DC (Tokuyama Corp.) e os agente de união (primers adesivos metálicos), Alloy Primer (Kuraray Co. Ltd. ), Metaltite (Tokuyama Corp.) e Cesead Opaque Primer (Kuraray Co. Ltd.). Discos cimentados sem primers serviram como grupo controle. Os resultados mostraram que houve diferença estatisticamente significante entre as duas ligas (Ni-Cr-Be –24,82 ± 7,6 MPa e Ni-Cr - 22,32 ± 7,9 MPa). Já para os cimentos houve superioridade adesiva do cimento Panavia F, que obteve média de resitência adesiva de 27,49 ± 4,8 MPa, sobre o cimento Bistite II, que obteve média de resistência adesiva de 19,63 ± 8,4 MPa. Os primers utilizados não apresentaram influência positiva sobre o Panavia F já que os grupos sem primer para esse cimento obtiveram média de 28,18 ± 5,6 MPa que é equivalente a média dos outros grupos com Panavia. Entretanto, para o cimento Bistite II DC os primers Alloy Primer e Metaltite obtiveram as menores médias, 12,7 ± 7,6 MPa e 15,71 ± 4,8 MPa respectivamente, enquanto sem primer, ou com o Cesead Opaque Primer, as médias foram significantemente superiores, 24.47 ± 6 MPa e 25.70 ± 6,8 Mpa respectivamente. Diante dos resultados conclui-se que os primers adesivos metálicos não potencializaram a adesão de cimentos resinosos adesivos sobre ligas de Ni-Cr. / The bond strength for resin and basic metals comes from the interaction between oxides in the metal surface and adhesive monomers in the composite resins composition. The literature shows that still are some questions about this interaction so this research intends to: verify if the presence of Be at Ni-Cr alloy plays some influence for this union, compare two resin luting cements at this function and study the influence the use of metal primers for noble metals in this mecanism of adhesion. After 2500 thermocycles, tensile bond strength tests were loaded at 160 specimens, which consisted of two metals discs with 6 mm in diameter and 2 mm thick from a Ni-Cr-Be alloy (Verabond – Aalba Dental Inc., Cordelia, CA-USA) bonded togheter and two metal discs from a Ni-Cr alloy (Durabond - Odonto Comercial Importadora Ltda, São Paulo, SP) bonded togheter. Diferent brand adhesive systems were used: the resin cements, Panavia F (Kuraray Co. Ltd.) and Bistite II DC (Tokuyama Corp.) and the metal primers, Alloy Primer (Kuraray Co. Ltd.), Metaltite (Tokuyama Corp.) and Cesead Opaque Primer (Kuraray Co. Ltd.). Nonprimed specimens served as control group. The results indicated that there is statiscal diferences beetwen the two alloys (Ni-Cr-Be –24,82 ± 7,6 MPa e Ni-Cr - 22,32 ± 7,9 MPa). Panavia F had founded greater bond strength (27,49 ± 4,8 MPa) than Bistite DC (19,63 ± 8,4 MPa). The metal primers did not show any positive influence for the Panavia bond strength when we considere that the no primer group had 28,18 ± 5,6 MPa bond strength media which were equivalente to the others Panavia´s groups. However for the Bistite cement, the bond strength for Alloy primer and Metaltite were the lower medias, 12,7 ± 7,6 MPa and 15,71 ± 4,8 MPa respectivally, while the no primer or the Cesead Opaque Primer groups showed superior medias 24,47 ± 6 MPa and 25,70 ± 6,8 MPa respectivally. The outcome of this research shows that the metal primers used did not incresead the bond strength between resin cements and Ni-Cr alloys.

Orientador: Giselle Maria Marchi Baron / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T19:05:45Z (GMT). No. of bitstreams: 1 Palialol_AlanRodrigoMuniz_M.pdf: 12504444 bytes, checksum: a578af5941e733ad7dd18243b934355c (MD5) Previous issue date: 2013 / Resumo: O objetivo desse estudo foi avaliar a resistência de união de cimentos resinosos experimentais contendo diferentes concentrações do sal de hexafluorfosfato de difeniliodônio (DPIHFP) à cerâmica reforçada por dissilicato de lítio, com ou sem aplicação do adesivo após o uso do silano. Para isso, cinco diferentes formulações de cimento foram confeccionadas utilizando como base os monômeros Bis-GMA e TEGDMA (na proporção 1:1 em massa) e 60% em peso de partículas silanizadas de vidro de bárioalumínio- silicato. O sistema fotoiniciador foi composto por 1 mol% de canforoquinona (CQ), 2 mol% de metacrilato de dimetilaminoetil (DMAEMA) e diferentes concentrações de DPIHFP: 0; 0,25; 0,5; 1 e 2 mol%, definindo assim, cinco formulações de cimentos resinosos experimentais. Como inibidor foi acrescido à mistura uma quantidade de 0,1 mol% de hidroxitolueno butilado e 60% em peso de partículas silanizadas de vidro de bário-alumínio-silicato foram incorporadas como carga inorgânica. Diante disso, a cimentação foi realizada com ou sem a aplicação do adesivo (Adper Scotchbond Multi- Purpose - Bond) estabelecendo assim, 12 grupos (n=7), sendo avaliados os cinco cimentos experimentais formulados e um cimento comercial (RelyX ARC). Foram confeccionados 84 espécimes de cerâmica IPS e.max (10 mm de comprimento x 10 mm de largura x 3 mm de espessura) e divididos, aleatoriamente, entre os 12 grupos previamente estabelecidos. Para todos os grupos foi realizado o condicionamento ácido da cerâmica (ácido hidrofluorídrico a 10%, 20 s) e aplicação de silano (RelyX Ceramic Primer). Logo após, os espécimes foram cimentados a blocos de resina fotopolimerizável Filtek Z250 (10 mm de comprimento x 10 mm de largura x 5 mm de espessura), utilizando os diferentes cimentos de acordo com o respectivo grupo, sob carga estática de 500 g, por 1 minuto. Para os grupos com utilização de adesivo, este foi aplicado 1 minuto após a aplicação do silano, sendo fotoativado através da cerâmica com LED 3a geração (Bluephase G2) a 1200 mW/cm2 juntamente com o cimento resinoso por 60 segundos. Após armazenamento (sob umidade relativa) em estufa por 24 horas a 37oC, as amostras foram seccionadas perpendicularmente à interface de união, gerando palitos de 1 mm2 (30 palitos por bloco) que foram submetidos ao ensaio de microtração em máquina de ensaio universal EMIC com velocidade de 0,5 mm/min. Foi realizado análise do padrão de fratura em lupa estereoscópica (Leica MZ75) com aumento de 40x e uma imagem representativa de cada padrão foi realizada em microscopia eletrônica de varredura. Os dados foram analisados através de Análise de Variância a dois critérios e teste Tukey, a um nível de significância de 5%. O cimento resinoso dual RelyX ARC apresentou os maiores valores de união, para os grupos com ou sem aplicação de sistema adesivo. Nos grupos com aplicação do sistema adesivo, os cimentos experimentais não diferiram estatisticamente entre si quanto à resistência de união. Nos grupos sem aplicação de adesivo, o cimento contendo 2mol% de DPIHFP obteve os menores valores de união. A aplicação do adesivo propiciou maiores valores de união somente para os cimentos RelyX ARC e DPIHFP 2mol%. De acordo com os resultados, pode-se concluir que a adição do sal de DPIHFP não foi capaz de aumentar os valores de união dos cimentos experimentais. O sistema de dupla ativação apresentou resistência de união à cerâmica superior aos cimentos experimentais fotoativados e a aplicação do adesivo promoveu o aumento dos valores de união apenas para os cimentos RelyX ARC e DPIHFP 2mol% / Abstract: The aim of this study was to evaluate the bond strength of experimental resin cements (ERCs) containing different concentrations of Diphenyliodonium Hexafluorphosphate (DPIHFP) salt to a lithium disilicate ceramic with or without the adhesive application after silane treatment. For this purpose, five ERCs were prepared using a Bis-GMA/TEGDMA (1:1 molar ratio) base compound with a 60% mass fraction of silanated Barium-Aluminum-Silicate glass fillers. The photoinitiator system was composed by 1 mol% of camphorquinone (CQ) 2 mol% of dimethylaminoethil methacrylate (DMAEMA) and different DPIHFP concentrations of 0, 0.25, 0.5, 1 or 2 mol%, resulting in five ERCs. As an inhibitor, 0.1mol% of hydroxyl butyl toluene was used. Therefore, the fixing protocol was performed with or without the application of adhesive (Scotchbond Multi-Purpose Adper - Bond) thereby establishing, 12 groups (n = 7), evaluating the five experimental resin cements and a commercial cement (RelyX ARC). Eighty four IPS e.max Press ceramic specimens (10 mm lenght x 10 mm width x 3 mm thickness) were fabricated and randomly divided among the 12 groups previously established. All the groups were etched with 10% hydrofluoric acid for 20 seconds and silane couple agent applied on the bond surface. After that, the specimens were fixed to photoactivated composite resin Filtek Z250 blocks (10 mm lenght x 10 mm width x 5 mm thickness), using different cements according to the respective group under static load of 500 g per one minute. For groups with adhesive application, this was applied 1 minute after applying the silane being cured by a third generation LED (Bluephase G2) together with the resin cement for 60 seconds. After storage for 24 hours at 37oC, the samples were sectioned perpendicular to the bond interface to obtain 1 mm2 sectional area beams (30 beams per sample) and submitted to a microtensile bond strength test in a universal testing machine EMIC, at a crosshead speed of 0.5 mm/min. The failure mode was analyzed by a stereomicroscope (Leica MZ75) at 40x magnification and one example of each type of failure mode was analyzed in scanning electron microscopy. Data were analyzed using ANOVA two criteria (ANOVA two-way) and Tukey test at a significance level of 5%. The dual resin cement RelyX ARC showed the highest bond strength values using or not the adhesive system. In groups with adhesive system, the ERCs were not statistically different from each other on the bond strength values to ceramics. In groups without adhesive system, the 2mol% of DPIHFP resin cement obtained the lowest bond strength values. The adhesive application led to higher bond strength values only for RelyX ARC and 2mol % DPIHFP resin cements. According to results, it can be concluded that the addition of DPIHFP salt was not able to increase the bond strength values of the experimental cements. The dual activation system showed higher values of bond strength when compared to photoactivated ERCs and adhesive system protocol increased the bond strength values only for the RelyX ARC and 2mol% DPIHFP resin cements / Mestrado / Dentística / Mestre em Clínica Odontológica

Electrical trees have long been the interest of the electrical insulation community due to their role in power systems equipment failure at locations where high divergent fields might arise due to impurities, contaminants or voids. Even through trees take a long time to grow in real life, they can be grown experimentally in shorter times under various conditions so that their growth characteristics can be investigated. Different samples have been fabricated to investigate the effects of interfaces in electrical tree propagation. Initially, the impact of an interface perpendicular to the electric field, and the interface position, thickness and/or composition on the polymer’s lifetime was investigated. In the results acquired, the positive impact of interfaces positioned perpendicular to the electric field was evident: increasing the samples’ time to breakdown as well as the electrical tree inception time. Due to the encouraging results, further investigation has been focused on interface modification and how this might be used to control the electrical tree growth as well as the samples’ time to breakdown. Altering the interface’s surface roughness using a number of different methods was carried out. Results were graphically and statistically analysed so that the any conclusions are robust, and uncertainties clear. The statistical analysis used by generating regression model equations was a novel method to predict how different electrical tree parameters were affected/affecting by others. In this way the dielectric’s lifetime could be predicted with a certain level of confidence. The modification of the interface by coating the surface with either a thin layer of pure or nano-filled (hexagonal Boron Nitride) epoxy resin resulted in it being impervious thus preventing the electrical tree to propagate through it. This was a novel method that showed that specific modification methods can significantly enhance the dielectric’s lifetime when applied appropriately. Details of new sample fabrication techniques are described which enable better control of the materials and interfaces, and data on tree length growth characteristics are discussed.

Magister Scientiae Dentium - MSc(Dent) / The shift towards minimally invasive dentistry has meant that dental practitioners are now undertaking procedures that are conservative and preserve as much of the existing tooth structure as possible. Repairing composite is a more conservative way of managing damaged restorations when compared to their replacement. A number of different protocols for repairing composite restorations exist but there is little information as to which is the most effective method. Aim: The aim of this study was to evaluate the effect the following treatment procedures have on the shear bond strength of repaired composite: i. Five different repair protocols, ii. Two different types of repair composite materials and iii. Aging in artificial saliva prior to repairing. Materials and methods: Two hundred and forty composite cylinders of 5mm diameter and 5mm height made from Filtek Supreme XTE (3M ESPE, St. Paul, MN, USA) were prepared with the aid of a silicon matrix. They were then divided into two groups: a hundred and twenty of these cylinders were aged in a solution of artificial saliva for 28 days and the remaining samples were left unchanged with no aging. All the aged and non-aged composite cylinders were then randomly allocated to six groups of twenty each corresponding to the repair protocol applied. The first group from both of the aged and non-aged samples was treated by roughening the top surface with a diamond bur followed by an application of Scotchbond 1XT (3M ESPE, St. Paul, MN, USA). The second group received a surface roughening with a diamond bur,etching with 35% phosphoric acid and application of Scotchbond 1XT. The third group received an application of Scotchbond Universal (3M ESPE, St. Paul, MN, USA) and the fourth one had a single application of Tetric N-Bond Universal (Ivoclar Vivadent AG, Schaan, Liechtenstein) on its top surface. The fifth group was treated by blasting with COJET Sand (3M ESPE, St. Paul, MN, USA) particles together with an application of Scotchbond Universal. The final group was used as the control where no surface treatment was done. After the surface treatments, each of the composite samples was repaired by the addition of fresh composite in the shape of cylinders measuring 3mm in diameter and 4mm in height. This was done with the aid of a silicon matrix. Within each treatment sub-group (n=20), 10 cylinders were repaired using either Filtek Supreme XTE or Tetric N-Ceram. All two hundred and forty repaired samples were then subjected to shear bond strength testing on a Universal testing machine. Data analysis: The results of the shear bond strength tests expressed in megapascals (MPa) were recorded and analysed for the effect of three different factors under consideration. The effectiveness of the repair protocols, type of composite and aging in artificial saliva were compared using the analysis of variance. Differences within the groups were identified using a post hoc analysis. Results: The mean highest repair shear bond strength was observed when COJET Sand in conjunction with Scotchbond Universal was used to repair the aged composite blocks. There were no significant differences in the shear bond strength observed when either Filtek Supreme XTE or Tetric N-Ceram was used as the repair composites. Aging in artificial saliva led to a mean reduction of 18.08% in the repair bond strength across the six treatment groups. Conclusions: The application of a surface treatment and intermediate adhesive is crucial in improving bond strength in the composite repair interface. Repair with Filtek Supreme XTE and Tetric N-Ceram was equally effective. Aging in artificial saliva produced significantly reduced bond strength.

Resin composites have been in the dental field for over forty years. They are now thought to be the most commonly used restorative material due to their aesthetic and mechanical properties. Although resin composites have high success rates as restorations, they do not offer all properties of an ideal restorative material. The aims of this research were to characterise the effects of variation in resin composite formulation on handling, mechanical; and physical properties. In particular the influence of the size and distribution of the inorganic components was investigated through the study of experimental formulations. Packing stress and viscosity were assessed with pentrometer principle at two different temperatures (23 and 37 ºC). It was found that filler size was strongly correlated with both packing stress and viscosity. Additionally, temperature has a dominant effect on packing stress and viscosity. Micro computed tomography [μCT] was used to investigate percentage of voids [% voids] in 3D dimensions. It was found that smaller filler size incorporated less % voids. In contrast filler size and disruption had a little effect on fracture toughness of resin composites. 3D surface topography was used to investigate the surface roughness before and after tooth brush abrasion. It was found filler size had a significant influence in both gloss retention and surface roughness (smaller filler size exhibited higher surface gloss). Finally, the effect of different storage media (distilled water, Coca Cola and red wine) on colour stability and gloss were investigated. It was found that dietary habits effect discolouration of resin composite restorations with the acidic drinks caused more staining.

En aéronautique, l’élaboration via des pré-imprégnés n’est pas toujours adaptées àla fabrication de nouvelles pièces de formes complexes ou de grandes dimensions. Desprocédés directs existent, dénommés Liquid Composites Molding (LCM), tels que leResin Transfer Moulding (RTM) ou les procédés d’infusion de résine, comme le LiquidResin Infusion (LRI) et le Resin Film Infusion (RFI). Actuellement, environ 5 à 10%des pièces composites sont fabriqués par ces procédés directs. Avec le procédé RTM,les tolérances dimensionnelles et la porosité peuvent être maîtrisées et on peut atteindredes pièces haute qualité, mais son industrialisation est complexe et les modèlesmécaniques doivent être améliorés pour réaliser des simulations représentatives. Parcontre, les procédés d’infusion peuvent être utilisés dans des conditions plus flexibles,par exemple, dans des moules ouverts à sac vide en nylon ou silicone, à faible coût. Parconséquent, les procédés de LRI et RFI sont particulièrement adaptés pour les petites etmoyennes entreprises car les investissements sont plus faibles par rapport à d’autresprocédés de fabrication.Les procédés par infusion de résine LRI ou RFI sont basés sur l’écoulement d’unerésine liquide (pour RFI, après le cycle de température, la résine solide obtenir son étatliquide) à travers l’épaisseur d’un renfort fibreux sec dénommé préforme.L’optimisation du procédé est difficile à réaliser car le volume de la préforme changefortement pendant le procédé car elle est soumise à une pression extérieure et qu’il n’ya pas de contre-moule. Pour optimiser les paramètres de fabrication des matériauxcomposites par infusion de résine, il est nécessaire de mettre en oeuvre un modèlenumérique. Récemment, une modélisation de l'écoulement d’un fluide isotherme dansun milieu poreux compressible a été développée par P. Celle [1]. Avec ce modèlenumérique, nous avons simulé des cas test en 2D pour des géométries industriellesclassiques. Pour valider ce modèle numérique, des essais d’infusion d’une plaque par leprocédé LRI dans des conditions industrielles ont été réalisés. D’une part, la simulationnumérique permet de calculer le temps de remplissage, l’épaisseur de la préforme et lamasse de la résine durant l’infusion. D’autre part, nous avons suivi de procédéexpérimentalement par des micro-thermocouples, la fibre optique et la projection defranges. Un des points clefs de l’approche expérimentale est que l’écoulement de larésine et le comportement de la préforme dépendent intrinsèquement de paramètres quiévoluent pendant l’infusion de la résine, tels que la variation de l’épaisseur, le temps deremplissage et le taux volumique de fibres, via la perméabilité. Enfin, une comparaisonentre les résultats expérimentaux et la simulation numérique permet de valider lemodèle numérique. Cette confrontation des résultats permettra de mettre en lumière lesdifficultés et les limites de ce modèle numérique, afin d’améliorer les futurs modèles.De plus, ces deux approches constituent un bon moyen d’étudier et d’approfondir nosconnaissances sur les procédés d’infusion de résine, tout en développant un outil desimulation indispensable à la conception de pièces composites avancées. / Weight saving is still a key issue for aerospace industry. For instance 50% in weightof the B787 and A350 aircraft structures is made of CFRP, so it is necessary to makelighter thick and complex parts. Direct processes called Liquid Composite Molding(LCM), such as Resin Transfer Moulding (RTM) or Resin Infusion Process (LRI, RFI).At the present time, around 5 to 10% of the parts are manufactured by direct processesand the current trend is clearly to go ahead. In RTM process, the dimensional tolerancesand porosity fraction can be kept under control and high quality parts produced, but itsindustrialisation is complex and refined models are still needed to perform simulations.On the contrary, the resin infusion process can be utilized in flexible conditions, such asin low cost open moulds with vacuum bags in nylon or silicone. This type of processonly requires low resin pressure and the tooling is less expensive than RTM rigidmoulds. Therefore LRI and RFI processes are particularity suitable for small andmedium size companies because the investments are rather low compared to othermanufacturing process.Liquid Resin Infusion (LRI) processes are promising manufacturing routes toproduce large, thick or complex structural parts. They are based on the resin flowinduced across its thickness by pressure applied onto a preform / resin stacking.However, both thickness and fibre volume fraction of the final piece are not wellcontrolled since they result from complex mechanisms which drive the transientmechanical equilibria leading to the final geometrical configuration. In order tooptimize both design and manufacturing parameters, but also to monitor the LRIprocess, an isothermal numerical model has been developed by P. Celle [1], whichdescribes the mechanical interaction between the deformations of the porous mediumand the resin flow during infusion. With this numerical model, we have investigated theLRI process with classical industrial piece shapes. To validate the numerical model andto improve the knowledge of the LRI process, the researcher work details a comparisonbetween numerical simulations and an experimental study of a plate infusion testcarried out by LRI process under industrial conditions. From the numerical prediction,the filling time, the resin mass and the thickness of the preform can be determined. Onanother hand, the resin flow and the preform response can be monitored bymicro-thermocouples, optical fibre sensor and fringe projection during the filling stage.One key issue of this research work is to highlight the major process parameterschanges during the resin infusion stage, such as the preform and resin temperature, thevariations of both thickness and fiber volume fraction of the preform. Moreover, thesetwo approaches are both good ways to explore and improve our knowledge on the resininfusion processes, and finally, to develop simulation tools for the design of advancedcomposite parts.

Orientador: Mário Alexandre Coelho Sinhoreti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-24T07:19:06Z (GMT). No. of bitstreams: 1 Leme_ArieneArcasTopalPaes_D.pdf: 1762862 bytes, checksum: df60c904446c386b9834989fa6847207 (MD5) Previous issue date: 2013 / Resumo: Neste estudo avaliou-se o efeito: (1) da adição de resina de troca aniônica (AER) a um cimento experimental, para reduzir a incompatibilidade entre sistemas adesivos simplificados e cimento resinoso de polimerização dupla, quando ativado quimicamente; (2) da aplicação de uma camada extra de adesivo entre o sistema adesivo simplificado e o cimento resinoso, na resistência da união, propriedades nanomecânicas da camada de cimento e micropermeabilidade na interface adesiva. Discos de resina composta foram cimentados com os sistemas adesivos ACE ALL Bond TE ([ACE] Bisco Inc.) e Scotchbond Universal ([SCU] 3M ESPE) ... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital. / Abstract: This study evaluated the effect of: (1) adding anion exchange resin (AER) to an experimental resin cement aiming to reduce incompatibility between simplified-step adhesive systems and dual-cured resin cement when chemically activated; (2) the application of an extra adhesive resin layer between the simplified adhesive system and resin cement, on the microtensile bond strength, nanomechanical properties of the cement layer and micropermeability at the adhesive layer. Resin composite discs were luted with the adhesive systems ACE ALL Bond TE ([ACE] Bisco Inc.) and Scotchbond Universal ([SCU] 3M ESPE) ... Note: The complete abstract is available with the full electronic document / Doutorado / Materiais Dentarios / Doutora em Materiais Dentários

Orientador: Taciana Marco Ferraz Caneppele / Banca: Eduardo Bresciani / Banca: Gabriela Queiroz de Melo Monteiro / Resumo: O objetivo deste estudo foi avaliar a efetividade de diferentes modos de foto ativação das resinas compostas bulk fill comparando com as resinas convencionais, analisando sua influência na irradiância, no grau de conversão, assim como na formação de fendas internas e marginais em restaurações classe II tipo slot vertical, após envelhecimento artificial. Cento e sessenta incisivos bovinos foram cortados e desgastados para simular dentes posteriores, nos quais foram realizados preparos classe II. Os espécimes foram divididos em quatro grupos de acordo com o material restaurador utilizado: Tetric N-Ceram Bulk Fill (TB), Admira Fusion X-tra Bulk fill (AB), Tetric N-Ceram (TC) e GrandioSO (GO). As resinas bulk fill foram inseridas em incremento único de 4 mm e nos demais grupos foi utilizada a técnica incremental oblíqua (2 mm). A foto ativação foi realizada com os aparelhos do tipo Monowave (MW) ou Polywave (PW) nos dois modos (alta intensidade continua e rampa). A medição da irradiância foi feita utilizando espectroradiômetro Patient Simulator (MARC-PS). O grau de conversão foi avaliado através da reflectância total atenuada (ATR) do espectrômetro (FTIR). As superfícies superiores das amostras foram irradiadas in loco durante 20 s. O espectro da superfície inferior foi registrado em tempo real e após 15 min da irradiação. As fendas foram avaliadas em estereomicroscópio (50x). As fendas marginais externas foram avaliadas antes e após a ciclagem termomecânica. Para fenda interna, ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to evaluate the influence of different photo activation modes on irradiance, the degree of conversion and formation of internal and external gaps in class II restorations using bulk fill resins. One hundred and sixty bovine incisors were cut and worn to simulate posterior teeth, in which class II preparations were performed. The specimens were divided into four groups according to the restorative material used: Tetric N-Ceram Bulk Fill (TB), Admira fusion X-tra Bulk fill (AB), Tetric N-Ceram (TC), GrandioSO (GO). The bulk fill resins were inserted in a single increment of 4 mm, and in the other groups, the incremental oblique technique was used. The photo activation was performed with a Monowave (MW) or Polywave (PW) light curing devices selecting two modes (high continuous intensity (HCI) and soft start (SS)). The irradiance measurement was performed using Patient Simulator (MARC-PS) in HCI and SS modes, for 20 s. For the degree of conversion, 2 mm and 4 mm high and 5 mm diameter molds were prepared for resin insertion directly on the attenuated total reflectance (ATR) spectrometer (FTIR). The upper surfaces of the samples were irradiated in situ for 20 s with the light curing apparatus in the modes (HCI) and (SS), the lower surface spectra was recorded continuously in real time and then at 15 min after irradiation. For the evaluation of the external gap each specimen was evaluated twice, one before and one after the thermomechanical cycling. ... (Complete abstract click electronic access below) / Mestre