Orientador: Luis Roberto Marcondes Martins / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T03:26:12Z (GMT). No. of bitstreams: 1 Macedo_VanessaCruz_M.pdf: 844488 bytes, checksum: b8556c9d46bb61e55024cbbffb39f017 (MD5) Previous issue date: 2009 / Resumo: O objetivo neste estudo foi avaliar o efeito do reembasamento (pinos anatômicos), do tipo de cimento e profundidade de cimentação sobre a retenção de pino de fibra de vidro. Para confecção das amostras, foram selecionados cento e oitenta incisivos bovinos, que tiveram suas porções coronárias removidas e seus canais tratados endodonticamente. Após tratamento endodôntico, os canais foram alargados com pontas diamantadas 4138 e 4137. As raízes foram divididas inicialmente em dois grupos: G1 - pinos de fibra de vidro sem reembasamento e G2 - pinos de fibras de vidro reembasados com resina composta (pinos anatômicos). Cada grupo foi dividido em três subgrupos de acordo com tipo de cimento utilizado: A - RelyX ARC, B - RelyX Unicem, e C - RelyX Luting. Em cada um destes subgrupos os pinos foram cimentados em três diferentes profundidades dentro do canal: 5 mm, 7,5 mm e 10mm, sendo utilizadas 10 raízes para cada subgrupo (n=10). Depois de preparadas, as amostras foram submetidas a ensaio de resistência à tração em uma máquina de ensaio universal, com velocidade de 0,5mm/min. Os resultados em kgf foram convertidos em MPa e submetidos ANOVA de três fatores com nível de significância de 95%, e as médias comparadas pelo Tukey. Os resultados demonstraram que não houve diferenças entre os cimentos resinosos RelyX ARC e o RelyX Unicem, quando cimentados em diferentes profundidades.O cimento RelyX Luting 2 apresentou os menores valores de resistência de união. Os pinos de fibra de vidro reembasados (pinos anatômicos) apresentaram valores maiores do que os pinos não reembasados. Através desses resultados pode-se concluir que os pinos reembasados (pinos anatômicos), cimentados a profundidade de 5 mm obtiveram os melhores resultados quando cimentados com os cimentos resinosos RelyX ARC e RelyX Unicem. / Abstract: This study evaluated the effect of the relining (anatomic posts), of type cements and the length of the luting on the retention of fiber glass posts. One hundred and eighty bovine incisors were selected, their coronary portion removed, and the canals endodontically treated. After endodontic treatment, the canals were extended with diamonds burs nº 4138 and 4137. The roots were divided initially in two groups: G1 - fiber glass posts without relining and G2 - fiber glass posts relined with composite resin (anatomic posts). Each group was subdivided in three subgroups according with the type of cements used: A - RelyX ARC, B - RelyX Unicem, and C - RelyX Luting. The subgroups were luting in three different length in the canals: 5 mm, 7.5 mm and 10 mm, totality 10 roots for each subgroup (n=10). All samples were submitted to tensile bond strength testing in a universal testing machine, with speed of the 0.5 mm/min. The results in kgf were converted in MPa and submitted by ANOVA three factors and significance level at 95%. The results displayed that there weren't difference between the resins cements RelyX ARC and RelyX Unicem, when luting in different length. The cement RelyX Luting 2, showed lowers values of bond strength. The fiber glass posts relined (anatomic post) showed higher values than those posts without relined. Could be concluded that the fiber glass posts relined (anatomic posts), luting in length of the 5 mm obtained the best results when luted with the resin cements RelyX ARC e RelyX Unicem. / Mestrado / Materiais Dentarios / Mestre em Materiais Dentários

Orientador: Mario Alexandre Coelho Sinhoreti / Dissertação (mestrado) - Universidade EStadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T09:01:20Z (GMT). No. of bitstreams: 1 Vitti_RafaelPino_M.pdf: 8432913 bytes, checksum: 82945cbea8656d59d74e27161eec09f2 (MD5) Previous issue date: 2009 / Resumo: O objetivo neste estudo foi medir e comparar a precisão dimensional de modelos de gesso confeccionados a partir de três técnicas de moldagem com dez diferentes elastômeros. Um modelo em cera, simulando um arco dental mandibular, teve retirados os dentes 44, 45 e 46 a fim de avaliar possíveis diferenças de precisão entre os lados direito e esquerdo, pelo maior volume de material de moldagem do lado direito, o que poderia acarretar em maior contração e conseqüentemente maior alteração desse lado. A partir desse modelo em cera foi obtido um modelo metálico padrão com pontos de referência nos dentes 33 (CE), 43 (CD), 37 (ME) e 47 (MD) que foi utilizado para a realização das moldagens. Foram medidas as distâncias entre os dentes CE-CD, ME-MD, CEME e CD-MD. Moldeiras metálicas de estoque foram usadas para as técnicas do reembasamento e dupla mistura. Já para a técnica da moldeira individual, moldeiras de resina acrílica foram confeccionadas com alívio interno de aproximadamente 2mm. Adesivos específicos para cada material foram usados nas moldeiras individuais, para promover adesão na moldeira. Todos os procedimentos de moldagem foram realizados em uma sala com temperatura e umidade relativa controladas. A manipulação dos materiais foi feita segundo as instruções dos fabricantes. O movimento de retirada da moldeira, após a presa do material de moldagem, foi padronizado por meio de um equipamento pneumático evitando possíveis distorções no molde. Os modelos de gesso foram vazados após trinta minutos da obtenção dos moldes, para promover a recuperação elástica dos materiais. Foram confeccionados cinco corpos-de-prova para cada marca comercial de elastômero e técnica de moldagem, totalizando cento e trinta amostras. Após 24 horas, foi feita a separação molde-modelo, sendo o modelo observado em microscópio comparador com 30x de aumento. Três leituras foram feitas em cada uma das distâncias analisadas, obtendo-se uma média que foi, posteriormente, analisada estatisticamente, por meio da análise de variância com três fatores ou com dois fatores e as médias comparadas pelo teste de Tukey (5%). Os resultados demonstraram que os silicones polimerizados por adição foram os materiais que mostraram melhores resultados de precisão dimensional dos modelos. Os silicones polimerizados por condensação apresentaram os piores resultados. Todas as distâncias mensuradas apresentaram alterações lineares negativas (contração), sendo que as distâncias ântero-posteriores (CEME e CD-MD) sofreram mais alterações quando comparadas com as distâncias transversais (CE-CD e ME-MD). Num contexto geral, não houve diferença entre as distâncias MD-CD e ME-CE. Também não foram encontradas diferenças entre as técnicas de moldagem. A precisão dos modelos de gesso foi mais afetada pelos materiais do que pela técnica de moldagem. / Abstract: The aim of this study was assess and compare the dimensional accuracy of stone models made from of three impression techniques and ten different elastomeric materials. A wax model, simulating a lower dental arch, had removed the teeth 44, 45 and 46 in order to evaluate possible differences of accuracy between the right and left sides, by the bigger volume of impression material on the right side that could lead in bigger contraction and, consequently, bigger change in this side. From this wax model was obtained a metallic master model with reference points in the teeth 33 (LC), 43 (LM), 37 (RC) and 47 (RM) that was used for the accomplishment of the impressions. The distances were measured among the teeth LC-RC, LM-RM, LC-LM and RC-RM. Stock metallic trays were used for the putty/wash technique and double mix technique. For the single mix technique custom acrylic resin trays were made with internal relief of approximately 2mm. Specific adhesives for each material were used in the custom trays, to promote adhesion in the trays. All impressions procedures were made at room with temperature and relative humidity controlled. The materials handled were made following the manufacturers' instructions. The tray movement, after the impression aterial set, was standardized through of a pneumatic equipment avoiding possible distortions in the mold. The stone models were pouring after thirty minutes of the molds obtaining, to promote the materials elastic recovery. Five specimens were made for each elastomeric material commercial mark and impression technique, totaling one hundred thirty samples. After 24 hours, the separation mold/model was made, being the model observed in measuring microscope at 30x magnification. Three measurements were made in each one of the analyzed dimensions, getting a mean that was later analyzed statistically through of variance analysis three-way or two-way and the means compared by Tukey's test (5%). The results demonstrated that addition silicones were the materials that showed better results of models dimensional accuracy. The condensation silicones showed the worst results. All distances assessed showed negative linear change (contraction), being that the anteroposterior distances (LCLM and RC-RM) suffered more changes when compared with the transversal distances (LC-RC and LM-RM). In general, there wasn't difference between the distances LC-LM and RC-RM. There wasn't found differences between the impression techniques. The stone models accuracy was more affected by the materials than the impression technique. / Mestrado / Mestre em Materiais Dentários

Orientador: Mário Alexandre Coelho Sinhoreti / Texto em português e inglês / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T12:41:50Z (GMT). No. of bitstreams: 1 Martins_AurealiceRosaMaria_M.pdf: 1504844 bytes, checksum: 8845f1f591540a2f3ae0518e7fc047e2 (MD5) Previous issue date: 2013 / Resumo: O objetivo neste estudo foi avaliar a utilização do isobornil metacrilato (IBOMA) como monômero diluente associado ou não ao TEGDMA, em resinas experimentais à base de Bis-GMA. No Capítulo 1, o grau de conversão (GC), a resistência à flexão (RF), o módulo de elasticidade (ME), a resistência máxima à tração (RMT), a profundidade de polimerização (PP) e a contração volumétrica (CV) foram avaliados. No Capítulo 2, a dureza Knoop (KHN), a densidade de ligações cruzadas (DLC) e a sorção (SOR) foram avaliadas. Nove formulações de matriz resinosa foram confeccionadas de acordo com o monômero diluente IBOMA, TEGDMA ou IBOMA / TEGDMA) nas proporções: Bis-GMA/IBOMA 60/40, 50/50, 40/60% em peso, Bis-GMA/TEGDMA 60/40, 50/50, 40/60% e quando associados Bis-GMA/IBOMA/TEGDMA, 60/20/20, 50/25/25 e 40/30/30%). Para o GC, os espécimes em formato de barras (7 x 2 x 1 mm / n=10) foram avaliados em espectroscopia de infravermelho transformada de Fourier (FTIR). Em seguida, os testes de RF e MF foram conduzidos numa máquina de ensaios universal, na mesma amostra utilizada para a avaliação do GC. A PP foi avaliada em amostras (n=5) confeccionadas, seguindo as instruções da ISO 4049. A densidade dos espécimes antes (?u) e após (?c) a fotoativação foram utilizadas para avaliar a CV, utilizando o princípio de Arquimedes. DLC foi avaliada através do teste de amolecimento; testes de KHN foram realizados antes e depois da imersão em etanol absoluto, durante 24 horas. O teste de SOR (n=5) foi realizado de acordo com as normas da ISO 4049. Os dados foram submetidos à análise de variância de dois fatores e teste de Tukey (?=0,05). As resinas Bis-GMA/TEGDMA apresentaram maiores valores de GC do que as resinas que continham IBOMA, exceto para a mistura com 60% em peso de Bis-GMA (p?0,001). As resinas com IBOMA apresentaram menor RF, MF e RMT do que outros grupos (p?0,001). A PP para as misturas de IBOMA, foi menor do que para os outros grupos (p?0,001), exceto para as resinas que continham elevada concentração de monômero diluente (Bis-GMA/TEGDMA, 40/60% em peso). As resinas Bis-GMA/ TEGDMA 60/40% e Bis-GMA/IBOMA/TEGDMA 60/20/20% apresentaram os valores mais elevados de dureza Knoop e as resinas Bis-GMA/IBOMA 50/50% e Bis-GMA/IBOMA 40 / 60% apresentaram os menores valores DLC. As resinas que continham TEGDMA apresentaram maior SOR. Pode-se concluir que o IBOMA diminuiu a contração volumétrica. No entanto, os copolímeros que contêm IBOMA sozinho apresentaram menores propriedades físico-mecânicas do que os sistemas Bis-GMA/TEGDMA e Bis-GMA/TEGDMA/IBOMA / Abstract: The purpose in this study was to evaluate the use of isobornyl methacrylate IBOMA as diluent monomer in the Bis-GMA/TEGDMA blends. In the Chapter 1 the degree of conversion (DC), flexural strength (FS), elastic modulus (EM), maximum tensile strength (MTS), depth of cure (DCU) and volumetric shrinkage (VS) were evaluated; In the Chapter 2 the Knoop hardness (KHN), crosslink density (CLD) and sorption (WS) were evaluated. Nine resin matrix formulations were made according to diluent monomer IBOMA, TEGDMA or IBOMA/TEGDMA in the following proportions: Bis-GMA/IBOMA 60/40, 50/50, 40/60 wt%, Bis-GMA/TEGDMA 60/40, 50/50, 40/60 wt% and when associated Bis-GMA/IBOMA/TEGDMA, 60/20/20, 50/25/25 e 40/30/30 wt%. DC was evaluated in bars (7 x 2 x 1 mm/ n=10) by Fourier transformed infrared spectroscopy (FTIR). FS and FM tests were conducted in a universal test machine in the same sample used to DC evaluation. DCU was evaluated in samples (n=5) made following the ISO 4049:2009 directions. The densities of samples before (?u) and after (?c) photoactivation were used to evaluate the VS using the Archimedes principle. CLD was evaluated through softening test; KHN tests were performed before and after immersion in absolute ethanol for 24 h. WS test (n = 5) was performed following the ISO 4049:2009 directions. Data were submitted to two-way ANOVA and Tukey?s test (?=0.05). The resins Bis-GMA/TEGDMA showed higher DC than resins containing IBOMA, except for the blend with 60 wt% Bis-GMA (p?0.001). The blends with IBOMA showed lower FS, EM and MTS than other groups (p?0.001). DCU for IBOMA blends was lower than other groups (p?0.001), except for the highest concentration of diluent monomer (Bis-GMA/TEGDMA, 40/60 wt%). The resins Bis-GMA/TEGDMA 60/40% and Bis-GMA/IBOMA/TEGDMA 60/20/20% showed the highest KHN values of and resins Bis-GMA/IBOMA 50/50% and Bis-GMA/IBOMA 40/60% showed the lowest CLD values. The resins containing TEGDMA showed higher WS. It can be concluded that IBOMA decrease the volumetric shrinkage. However, copolymers containing IBOMA alone showed lower physical-mechanical properties than Bis-GMA/TEGDMA and Bis-GMA/IBOMA/TEGDMA systems / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Orientador: Marcelo Giannini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T14:52:05Z (GMT). No. of bitstreams: 1 Pacheco_RafaelRocha_M.pdf: 2265970 bytes, checksum: 2ea85fa1c09029765d270c2e28f5ebf7 (MD5) Previous issue date: 2013 / Resumo: O objetivo do estudo foi avaliar o comportamento da luz, em diferentes comprimentos de onda, através de materiais restauradores indiretos com diferentes espessuras. A análise da passagem de luz foi realizada, através de quatro materiais restauradores odontológicos confeccionados pela técnica do CAD/CAM: uma resina composta indireta (RC) (Lava Ultimate, 3M ESPE), uma cerâmica feldspática (CF) (VitaBlocs, VITA) e duas cerâmicas à base de zircônia (ZK) (Katana, Noritake) e (ZL) (Lava, 3M ESPE). A perda total de irradiância, assim como a perda de energia em comprimentos de onda específicos (azul e violeta) foram analisados. As amostras sinterizadas tinham as dimensões de 20x20 mm, com variação na espessura: 0,5 mm, 1,0 mm, 1,5 mm e 2,0 mm (n=5). Uma fonte de luz de arco de plasma de alta potência com amplo espectro de luz foi utilizada (Arc Light II, Air Technologies). A caracterização dessa fonte de luz foi realizada através da avaliação da irradiância (mW/cm2), determinação dos espectros emitidos pela fonte de luz e padrão de saída pela ponta do aparelho. Para avaliar a quantidade de luz que passa através do material foi utilizado um espectroradiômetro (DAS 2100, Labsphere Inc.). Os corpos de prova foram posicionados sobre a superfície de uma lamínula de vidro que estava localizada na esfera integradora. O aparelho fotoativador foi posicionado de forma que a ponta do aparelho tocasse levemente e paralelo à superfície da amostra. Os dados foram tabulados e submetidos à análise estatística (análise de variância de dois fatores e teste de Tukey (?=0,05)). A interposição do material restaurador com 0,5 mm de espessura provocou uma perda de energia por volta de 60% e o aumento da espessura do material provocou redução da irradiância através dos mesmos. O material que apresentou menor perda de energia nas espessuras de 1,0 a 2,0 mm foi CF. A RC com espessura de 0,5 mm apresentou perda de energia de 56,2% e, com o aumento dessa espessura para 1,0 mm, essa perda de energia aumentou para 75,4%, semelhante à perda observada nas cerâmicas à base de zircônia. Os materiais RC, ZK e ZL apresentaram os maiores valores de perda de energia irradiante em até 1,0 mm de espessura. Com 1,5 mm e 2,0 mm, os materiais que apresentaram maior perda de energia foram: RC e ZK. Para todos os materiais, observou-se aumento significativo na perda de energia com o aumento da espessura do material e essa perda de energia foi dependente do tipo de material protético. A luz violeta (350 a 425 nm) apresentou menor capacidade de penetração quando comparada a luz azul para todas as espessuras e tipos de material restaurador indireto / Abstract: The aim of this study was to evaluate the light behavior, in different wavelengths, through different restorative materials with different thicknesses. The analysis was conducted using four dental restorative material obtained by the technique of CAD/CAM technology: an indirect composite resin (CR) (Ultimate Lava, 3M ESPE), a feldspathic ceramic (FC) (VITABLOCS, VITA) and two zirconia based ceramics (ZK) (Katana, Noritake) and (ZL) (Lava, 3M ESPE). The total loss of irradiance as well as the loss of energy at specific wavelengths (blue and violet) was analyzed. The sintered samples had dimensions of 20x20 mm, with a variation in thickness of 0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm (n = 5). A plasma arc light source with high power and broad spectrum of light was used (Arc Light II, Air Technologies). The characterization of this light source was performed by evaluating the irradiance (mW/cm2), determining the spectra emitted by the light source and the output pattern on the tip of the device. To assess the amount of light passing through the material a spectroradiometer was used (DAS 2100, Labsphere Inc.). The specimens were placed on the surface of a thin glass (0.1 mm) located on the opening of the integrated sphere. The tip of the curing unit was positioned in parallel and lightly touching the sample surface. Data were tabulated and subjected to statistical analysis (two way ANOVA and Tukey test (? = 0.05)). The interposition of a restorative material of 0.5 mm thickness caused a loss of energy of approximately 60% and with the increase of the material thickness there was a reduction of the irradiance. The material that showed less energy loss in thickness from 1.0 to 2.0 mm was FC. CR with a thickness of 0.5 mm showed energy loss of 56.2%, and with 1.0 mm, this energy loss increased to 75.4%, similar to the loss observed in zirconia based ceramics. CR, ZK and ZL showed the highest values of radiant energy loss by up to 1.0 mm thick. With 1.5 mm and 2.0 mm, the materials with higher energy loss were: CR and ZK. For all materials, there was a significant increase in energy loss by increasing the thickness of the material and that energy loss is dependent on the type of indirect material. The violet light (350-425 nm) showed lower penetration capability compared to blue light for all thicknesses and types of indirect restorative material / Mestrado / Materiais Dentarios / Mestre em Materiais Dentários

Orientador: Simonides Consani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T03:44:51Z (GMT). No. of bitstreams: 1 Guiraldo_RicardoDanil_M.pdf: 364199 bytes, checksum: 276b6a4ebf54255a1b8a3ee68f8b30de (MD5) Previous issue date: 2005 / Resumo: O estudo avaliou o efeito dos tipos de incremento, de fotoativação e as fases restauradoras nas variações térmicas ocorridas na câmara pulpar, durante a fotoativação do compósito Filtek Z250. Foram utilizados 90 incisivos bovinos, nos quais foram feitos preparos cavitários (3x3x2,5mm) padronizados. Os dentes foram separados aleatoriamente em 3 grupos, de acordo com o tipo de fotoativação por luz halógena: 1- contínua (700 mW/cm2 por 20 s); 2- dupla intensidade (inicial de 100 mW/cm2 por 5 s, seguido de 700mW/cm2 por 15 s); 3- intermitente (2 s de ativação com 700mW/cm2, seguido do mesmo tempo pela ausência de luz, total de 40 s). Os grupos foram separados em 3 subgrupos segundo o tipo de incremento: 1- único; 2) oblíquos (três incrementos, um colocado nas paredes cervical e axial, outro nas paredes incisal e axial e o último unindo os dois); 3) horizontal/verticais (o horizontal foi colocado na parede axial, um vertical na parede cervical e o outro na parede incisal), totalizando 9 grupos (n=10). As cavidades foram condicionadas com ácido fosfórico por 20 s, o sistema de união Single Bond e o compósito Filtek Z250 aplicados segundo os protocolos de fotoativação e incremento. As restaurações foram realizadas em ambiente controlado (37ºC e 50±10% UR) e as temperaturas registradas com termômetro digital acoplado ao termopar tipo-K introduzido no canal radicular, de maneira que ficasse em contato com a dentina da câmara pulpar, correspondente à parede axial do preparo. Os dados obtidos foram submetidos à análise de variância e as médias ao teste de Tukey em níveis de 5% e 1%. A média de temperatura do incremento único (37,14ºC) foi significantemente menor que dos incrementos oblíquos (37,44ºC) e horizontal/verticais (37,43ºC). A luz contínua promoveu valor de temperatura (37,53ºC) estatisticamente superior aos demais tipos de luz, os quais não deferiram (37,27ºC e 37,21ºC). A fotoativação do adesivo foi estatisticamente maior (37,54ºC) que na aplicação do adesivo (36,82ºC) e na ativação do compósito (37,20ºC). Na interação tipo de incremento-tipo de fotoativação, na luz contínua o maior calor foi promovido pelo incremento horizontal/verticais, estatisticamente diferente dos demais. Na dupla intensidade, a maior temperatura foi no incremento oblíquo, diferente dos demais, enquanto na pulsátil não houve diferença. Para o incremento único não houve diferença quanto à fotoativação, enquanto no oblíquo a luz pulsátil promoveu valor significantemente menor. No incremento horizontal/verticais, a luz contínua foi estatisticamente superior. Na interação tipo de incremento-fase restauradora, o calor do incremento único foi estatisticamente superior na fotoativação do adesivo, seguido pela fotoativação do compósito e aplicação do adesivo. Para os incrementos oblíquo e horizontal/verticais, a fase aplicação do adesivo foi significantemente menor. Para as fases restauradoras não houve diferença estatística entre aplicação e fotoativação do adesivo, entretanto na fotoativação do compósito, o incremento único foi significantemente menor. Na interação tipo de fotoativação-fase restauradora, em todas as fotoativações não houve diferença estatística no calor das fotoativações dos adesivo e compósito, diferindo estatisticamente da fase aplicação do adesivo. Para as fotoativações do adesivo e do compósito, o calor produzido pela luz contínua foi significantemente maior, enquanto na aplicação do adesivo não houve diferença estatística. Houve influência das variáveis sobre o calor que atingiu a câmara pulpar / Abstract: This study evaluated the effect of the increment insertion and light-curing methods on thermal variations in the pulp chamber during Filtek Z250 composite resin light-curing. Standard cavities (3x3x2.5mm) were prepared in 90 bovine incisors. The teeth were randomly assigned into 3 groups, according to each light-curing method: 1- continue halogen light (700 mW/cm2 per 20s); 2- halogen light with a soft-start mode (initial intensity of 100 mW/cm2 per 5s obtained with a spacer and 700mW/cm2 per 15s, totalizing 20s); 3- intermittent halogen light (2s of activation with 700mW/cm2, followed by the same time of light absence, totalizing 40s). All groups were divided into 3 subgroups according to each type of increment: 1- bulk; 2- oblique (three increments, one in the cervical and axial walls, one in the incisal and axial walls, and finally one joining the the other two); 3- horizontal/vertical (the horizontal in the axial wall, one vertical in the cervical wall and another vertical in the incisal wall), totalizing 9 groups (n=10). All cavities were etched with phosphoric acid for 20s; the adhesive system Single Bond and the resin composite Filtek Z250 were applied according to the types of light-curing and increment. All experiments were carried out in controlled environment (37 Celsius degree and 50±10% relative humidity). The temperature variations (Celsius degree) were obtained using a digital thermometer attached to a type-K thermocouple which was inserted into the root canal as to be in contact with the pulp chamber dentine, correspondent to the axial wall of the cavity. Data were submitted to ANOVA and mean values compared by the Tukey¿s test with significance levels of 5% and 1%. The mean temperature (37.14) of the bulk increment was significantly lower than that oblique (37.44) and horizontal/verticals (37.43) increments. The continue light-curing revealed temperature mean values (37.53) statistically higher than those observed for the other types of light (37.27 and 37.21), which did not differ from each other. The adhesive light-curing showed statistically higher temperatures (37.54) than those observed during the adhesive application (36.82) and resin composite light-curing (37.20). In relation to the interaction between the light-curing method and type of increment, the horizontal/vertical increment under continue halogen light showed the highest temperature values, statistically different from the others. As for the soft-start light-curing method, the highest temperature was observed for the oblique increment, statistically different from others; no difference was observed for the intermittent halogen light. For the bulk increment, no statistically significant differences were observed among groups concerning the light-curing methods; however, in the oblique increment, the intermittent light revealed lower temperature values. For the horizontal/vertical increment, the continue light-curing temperature was statistically higher. For the interaction between type of increment and the restorative phase, the bulk increment heat was statistically higher in the adhesive light-curing phase, followed by the resin composite light-curing and adhesive application. The horizontal/vertical and oblique increments revealed significantly lower temperature values during adhesive application. In the restorative phases, no difference was observed between adhesive application and adhesive light-curing. However, in the resin composite light-curing, the bulk increment showed significantly lower temperature values. For the interaction between type of light-curing and restorative phase, no statistical difference was observed for all light-curing methods concerning adhesive and resin composite light-curing, differing only in the adhesive application phase. For the adhesive and resin composite light-curing phases, the heat produced by continue light was significantly higher. No statistically significant difference was verified for adhesive application. There was influence of the variables on the heat that reached the pulpar chamber / Mestrado / Materiais Dentarios / Mestre em Materiais Dentários

Orientador: Regina Maria Puppin Rontani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-22T09:19:07Z (GMT). No. of bitstreams: 1 Sampaio_CamilaSobral_M.pdf: 4499191 bytes, checksum: e827ca1cd97b2ad41e3b5fdf21d70308 (MD5) Previous issue date: 2013 / Resumo: O objetivo deste estudo foi avaliar a interface dente/restauração classe V realizada com diferentes sistemas adesivos (condicionamento total e auto-condicionante) e compósitos restauradores (baixa contração e convencional), submetidas à termociclagem (TC), por meio de Tomografia por Coerência Óptica (OCT) e infiltração por nitrato de prata em Microscopia Eletrônica de Varredura (MEV). Foram utilizados 90 terceiros molares humanos livres de cárie, onde foram realizados preparos tipo Classe V (0,7 mm/profundidade x 2 mm/diâmetro), com margens localizadas em esmalte e dentina. Os dentes foram distribuídos aleatoriamente em 6 grupos de 15 dentes cada, de acordo com o sistema adesivo e compósito restaurador utilizado: Grupo 1 - Adper Single Bond 2 (SB2) + Aelite LS Posterior (AP); Grupo 2 - SB2 + Venus Diamond (VD); Grupo 3 - SB2 + Filtek Z250 XT (Z250); Grupo 4 - Clearfil SE Bond (CSE) + AP; Grupo 5 - CSE + VD; Grupo 6 - CSE + Z250. Todos os grupos foram avaliados pré e pós TC por OCT (n=10). Após a TC (1000 ciclos entre 5 e 55°C), 5 dentes de cada grupo foram selecionados aleatoriamente para a realização da infiltração por nitrato de prata. Para cada grupo, outros 5 dentes foram preparados e não submetidos à TC, também para esta avaliação. A infiltração por prata foi visualizada em MEV em aumentos de 50x e 1000x, e posteriormente classificados por escores: 0-sem infiltração; 1- infiltração em camada híbrida; 2- infiltração em camada híbrida e túbulos dentinários; e 3- infiltração em camada híbrida, túbulos dentinários e sistema adesivo. Para a análise das imagens geradas por OCT, foi utilizado o programa Image J. As interfaces esmalte e dentina foram analisadas separadamente. Os dados foram submetidos à análise estatística de metodologia de modelos mistos para medidas repetidas (PROC MIXED para medidas repetidas) e teste de Tukey Kramer (p?0,05%). Para interfaces em dentina, observou-se interação significativa entre sistema adesivo e TC; as restaurações com o sistema adesivo CSE, após TC, apresentaram menores porcentagens de fendas na interface dente/restauração, para todos os compósitos, em comparação com o sistema adesivo SB2. Os resultados após a realização da TC demonstraram maiores valores de fendas, quando comparadas às mesmas amostras previamente à sua realização. Em esmalte, não foram observadas fendas na interface dente/restauração, tanto previamente quanto posteriormente à TC, para os sistemas adesivos e compósitos. Foi realizada análise estatística descritiva para a infiltração por nitrato de prata. A análise de infiltração por prata, tanto previamente quanto posteriormente à TC, não mostrou infiltração em esmalte. Com relação à dentina, houve um aumento no percentual de fendas para todos os sistemas adesivos e compósitos restauradores posteriormente à realização de 1000 ciclos térmicos. Pode-se concluir que, dependendo do sistema adesivo utilizado, a TC pode produzir maiores índices de fendas na interface dente/restauração, para todos os compósitos / Abstract: The aim of this study was to evaluate the tooth / class V restoration interface accomplished by different adhesive systems (total and self-etching) and restorative composites (low shrinkage and conventional), submitted to thermal cycling (TC), using Optical Coherence Tomography (OCT) and silver nitrate leakage by Scanning Electronic Microscope (SEM). It was used 90 human caries free third molars, with class V preparations (0.7 mm/ 2 mm x depth/diameter), with margins located in enamel and dentin. The teeth were randomly divided in 6 groups of 15 teeth each, according to the adhesive and composite restorative system used: Group 1- Adper Single Bond 2 (SB2) + Aelite LS Posterior (AP); Group 2- SB2 + Venus Diamond (VD); Group 3- SB2 Filtek Z250 + XT (Z250); Group 4- Clearfil SE Bond (CSE) + AP; Group 5- CSE + VD; Group 6- CSE + Z250. All groups were subjected to pre and post thermal cycling by OCT evaluation (n=10). After TC (1,000 cycles between 5 and 55°C), 5 teeth of each group were randomly selected for the silver nitrate leakage evaluation. For each group, 5 other teeth were prepared and were not subjected to TC, also for this evaluation. The silver nitrate leakage was observed in SEM in 50x and 1,000x magnification and subsequently classified by scores: score 0- without infiltration; 1- infiltration in the hybrid layer; 2- infiltration in the hybrid layer and dentinal tubules; and 3- infiltration in the hybrid layer, dentinal tubules and adhesive. For the analysis of images generated by the OCT, it was used the Image J software. The enamel and dentin interfaces were analyzed separately. Data were submitted to statistical analysis of mixed model methodology for repeated measurements (PROC MIXED for repeated measurements) and the Tukey Kramer Test (p?0.05). For dentin interfaces, it was observed that there was a significant interaction between adhesive and TC; the restorations with CSE adhesive system, after TC, showed smaller percentages of gaps at the dentin / restoration interface, for all composites, comparing to the SB2 adhesive system. With respect to thermal cycling, the results after their achievement showed lower values of interfacial adaptation, when compared the same samples prior to their implementation. In enamel, it was not observed gaps in the interface, both pre and post-TC, for all composite and adhesive systems. Descriptive statistics was used to analyze silver nitrate leakage. For the analysis of silver nitrate leakage, it was observed that there was no infiltration by silver nitrate in enamel both before and after TC. With respect to dentin, there has been an increase in the marginal failure rates for all adhesive systems and restorative composites after 1000 thermal cycles. It can be concluded that, depending on the adhesive system, TC can provide higher percentage of gaps at the tooth/restoration interface, for both studied composites. CSE provided improved interfacial adaptation than SB2 / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Magister Scientiae Dentium - MSc(Dent) / The aim of this study was to determine whether the presence or absences of the root canal seal had any influence on the retrograde sealing ability of MTA (mineral trioxide aggregate). / South Africa

OBJECTIVES: To determine the effects of sintering cycle and curing technique on the translucency, refractive index and flexural strength of novel polymer-infiltrated ceramics. MATERIALS AND METHODS: Alumina and spinel matrix specimens were fabricated by slip casting (15mm diameter × 2mm thickness). Alumina and spinel specimens were divided into 7 and 6 groups respectively (n=10/group). Alumina groups AHP1, AH1and AM1 were sintered at 1150°C, groups AHP2, AH2 and AM2 at 1200°C and group AFD was fully sintered at 1550°C. Spinel groups SHP1, SH1 and SM1 were sintered at 1500°C and groups SHP2, SH2, SM2 at 1600°C. Density was calculated for each specimen. Groups AM1, AM2, AFD, SM1 and SM2 were the control groups and received no further treatment. Other groups were silanated and dried overnight at 90°C. Then, UDMA-TEGDMA (50-50 mole) resin was prepared and infiltrated into the ceramic specimens under vacuum. Groups AHP1, AHP2, SHP1 and SHP2 were cured by heat at 90°C under pressure of 138 MPa. Groups AH1, AH2, SH1 and SH2 were cured by heat at 90°C. Specimens were polished (1.5mm thickness) and density measured. The total transmission was evaluated with a spectrophotometer (X-rite Ci7600). Refractive index was measured (Presidium Refractive Index Meter II). Biaxial flexural strength was obtained (Instron 5566A) with a crosshead speed of 0.5mm/min. The microstructure was examined using a field emission scanning electron microscope (FESEM-VP, Hitachi SU6600). Statistical analyses were performed using Excel 2016 (Microsoft Office) and JMP 13 (SAS). RESULTS: Polymer-infiltrated alumina and spinel showed significantly lower refractive index (p< .0001), higher translucency (p< .0001) and higher flexural strength (p< .0001) than their corresponding ceramic matrix groups. Sintering temperature of the ceramic matrix had a significant influence on the flexural strength of polymer-infiltrated ceramics. The application of pressure during polymerization significantly improved the translucency but did not influence significantly the flexural strength of polymer-infiltrated ceramics. Groups AHP2 and AH2 showed high strength (comparable to fully sintered alumina). Polymer-infiltrated spinel showed better translucency but lower strength than alumina groups. CONCLUSION: Sintering temperature and curing technique had a significant influence on optical and mechanical properties of polymer-infiltrated ceramics. / 2020-10-24

The key to species survival depends on the ability to reproduce. In mammals ovulation requires a precisely timed luteinizing hormone (LH)-surge on the afternoon of proestrus. It is thought that this LH-surge requires the convergence of two signals one being a hormonal signal (i.e. the positive feedback of estrogen) and the other being a neural signal (i.e. a circadian signal). The circadian clock is known to be involved in regulating numerous biological functions, such as sleep/wake cycles, food intake, body temperature, hormonal regulation, etc. It does this through a series of transcriptional/translational feedback loops involving various clock genes (i.e. Clock, Bmal1, Per1, Per2, Cry1, Cry2, reverbα, etc.). CLOCK and BMAL1 bind to noncanonical E-boxes in the promoters of clock driven genes, which activates their own transcription and subsequent translation. PER and CRY are then translocated back into the nucleus to inhibit their own transcription and that of other E-box driven genes. There have been various published reports on clock mutant animals having impaired fecundity. Mammalian reproduction occurs through the hypothalamic-pituitary-gonadal (HPG) axis where GnRH (gonadotropin-releasing hormone) neurons, located in the hypothalamus, release GnRH in a pulsatile fashion. GnRH acts on the GnRH receptor (GnRHR) on the surface of anterior pituitary cells called gonadotropes. The GnRHR triggers the synthesis and release of LH and FSH, which act on the ovaries to produce estrogen and progesterone. Estrogen then feeds back on the hypothalamus and pituitary gland. In the present studies whole rat pituitaries were used to assess clock gene and protein expression at diestrus a.m./p.m. and proestrus a.m./p.m. It was found that mPer1 increased during the evening of both days, but peaked on the evening of proestrus. It was surprising that PER1 protein was also high during the morning of proestrus, which was not seen in mPer1 mRNA. Since LH is synthesized and secreted only in gonadotropes, which make up 3-5% of the entire pituitary, enriched primary gonadotropes were used to study clock gene expression. Using enriched primary gonadotropes it was seen that mPer1 is indeed expressed in these cells in a rhythmic fashion and also that GnRH induces mPer1 as well as LHβ. Because GnRH induces both mPer1 and LHβ, experiments were performed to determine whether the signaling pathway involved in the GnRH induction of mPer1 correlates to that of the GnRH induction of LHβ. Using various pharmacological approaches it was demonstrated that GnRH induces mPer1 and LHβ through the PKC/MAPK pathways. It has also been shown that the GnRH induction of LHβ requires the early growth response protein 1 (Egr-1). To ascertain the importance of Egr-1 in mPer1 expression, analysis of the mPer1 promoter was performed and an Egr-1 binding site was found. Using various techniques it was determined that Egr-1 is involved in the GnRH induction of mPer1 expression. GnRHR expression fluctuates in accordance with the frequency of GnRH pulses. Little is known about how this change in GnRHR expression occurs. E-boxes are required for circadian regulation of a gene. Through examination of the GnRHR promoter, seven noncanonical E-boxes were found proximal to the transcriptional start site (tss). Analysis of the putative clock gene regulation of the GnRHR was performed and it was found that clock genes are indeed important factors in controlling GnRHR expression. To reach the critical LH-surge, LHβ must be synthesized and released from the gonadotropes. To further the understanding of clock gene involvement in the HPG axis, the LHβ promoter was also examined and six noncanonical E-boxes were found proximal to the tss. Chromatin immunoprecipitation was performed, and it was seen that CLOCK and BMAL1 bind to these E-boxes in the LHβ promoter. To determine whether these elements play a role in the regulation of the LHβ each E-box was mutated to a nonsensical sequence using site-directed mutagenesis. The impact on LHβ expression was analyzed via luciferase reporter activity. Through these techniques it was established that clock genes play an important role in regulating LHβ. These data demonstrate a complex variety of ways by which the circadian clock is involved in the regulation of the reproductive neuroendocrine axis. / A Dissertation Submitted to the Department of Biomedical Sciences in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Summer Semester, 2009. / June 18, 2009. / Egr1, GnRH, Per1, HPG, Fertility, Circadian Rhythms / Includes bibliographical references. / James Olcese, Professor Directing Dissertation; Laura Keller, Outside Committee Member; Mohamed Kabbaj, Committee Member; Charles Ouimet, Committee Member.

Circadian rhythms in mammals are generated by a negative transcriptional feedback loop in which PERIOD (PER) is rate-limiting for feedback inhibition. Casein kinases Iδ and Iε (CKIδ/ε) can regulate temporal abundance/activity of PER by phosphorylation-mediated degradation and cellular localization. Despite their potentially crucial effects on PER, it has not been demonstrated in a mammalian system that these kinases play essential roles in circadian rhythm generation as does their homolog in Drosophila. To disrupt both CKIδ/ε while avoiding the embryonic lethality of CKIδ disruption in mice, we used CKIδ-deficient Per2Luc mouse embryonic fibroblasts (MEFs) and overexpressed a dominant-negative mutant CKIε (DN-CKIε) in the mutant MEFs. CKIδ-deficient MEFs exhibited a robust circadian rhythm, albeit with a longer period, suggesting that the cells possess a way to compensate for CKIδ loss. When CKIε activity was disrupted by the DN-CKIε in the mutant MEFs, circadian bioluminescence rhythms were eliminated and rhythms in endogenous PER abundance and phosphorylation were severely compromised, demonstrating that CKIδ/ε are indeed essential kinases for the clockwork. This is further supported by abolition of circadian rhythms when physical interaction between PER and CKIδ/ε was disrupted by overexpressing the CKIδ/ε binding domain of PER2 (CKBD-P2). Interestingly, CKBD-P2 overexpression led to dramatically low levels of endogenous PER, while PER-binding, kinase-inactive DN-CKIε did not, suggesting that CKIδ/ε may have a noncatalytic role in stabilizing PER. Our results show that an essential role of CKIδ/ε is conserved between Drosophila and mammals, but CKIδ/ε and DBT may have divergent non-catalytic functions in the clockwork as well. Since reversible phosphorylation events in the circadian clock are thought to be involved in temporal regulation of clock proteins, a dynamic process of clock proteins mediated by protein kinases and phosphatases may be an essential feature in the time-keeping mechanism in mammals. To address these issues more definitively and extend findings that CKIδ/ε are essential for the clockwork, we proposed to explore the dynamics of reversible PER phosphorylation by studying CKIδ/ε conditional mutant mice / cells and by identifying protein phosphatases in targeting PER and characterizing them using genetic and biochemical approaches. We finally validated that CKIδ/ε are essential protein kinases to facilitate driving clockwork based on our findings that CKIδ/ε double KO cells have no circadian rhythms and x they are rescued by transducing CKIε. Moreover, PP1 is highly associated with PER dephosphorylation based on our results in genetic (dominant negative PP1) and chemical approaches (phosphatase inhibitors: OA vs. CA). Therefore, we propose that dynamic and reversible processes mediated by kinases and phosphatases are essential features in the timedriving/ keeping mechanism in mammals. / A Dissertation submitted to the Department of Biomedical Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2010.. / October 15, 2010. / Mouse embryonic fibroblast, Dominant negative, Casein kinase, Circadian clock / Includes bibliographical references. / Choogon Lee, Professor Directing Dissertation; James Fadool, University Representative; Mohamed Kabbaj, Committee Member; James Olcese, Committee Member; Yoichi Kato, Committee Member.