Orientador: Mario Fernando de Goes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T03:08:16Z (GMT). No. of bitstreams: 1 Lima_RenallyBezerraWanderleye_M.pdf: 1436974 bytes, checksum: 1ffe21bf86f88b2af39db7e176ccc1b2 (MD5) Previous issue date: 2015 / Resumo: O objetivo deste estudo foi avaliar a resistência à flexão biaxial (RFB) de cimentos resinosos dual, submetidos a diferentes métodos de ativação e armazenados no período de 15 min, 24h e 6 meses. Os cimentos resinosos (RelyX Unicem 2 automix (autoadesivo) (RU) e Variolink II (convencional) (VL) foram manipulados e inseridos em moldes de teflon (0,5 mm de espessura x 6,5 mm de diâmetro), posicionados em superfície com temperatura controlada (35°C). Foram confeccionados 120 espécimes de cada material, os quais foram divididos em grupos de acordo com o período de armazenamento (15 min, 24h e 6 meses) (n=40) e em subgrupos de acordo com os métodos de ativação (n=10) a seguir: auto-polimerização, fotoativação direta (FD), fotoativação direta com distância de 6 mm entre a ponta do aparelho de luz e o espécime (PD) e fotoativação indireta (anteparo de resina composta de 6 mm) (FI). Os espécimes fotoativados foram expostos à luz visível por 40s (56 J/cm2). O ensaio de resistência à flexão biaxial foi realizado em uma máquina de teste universal (model 1144, Instron Corp, Norwood, MA, USA) com velocidade de 1.27 mm/min, após cada período de armazenamento Os valores de RFB foram submetidos à análise de variância (ANOVA) de 3-fatores e teste de Tukey post-hoc (p=0,05). A análise de variância demonstrou significativa interação entre os materiais, período de armazenamento e método de ativação (p< 0.0001). Os valores de RFB pelo método de auto-polimerização foram estatisticamente inferiores em relação aos outros métodos de ativação, em todos os períodos de armazenamento, para ambos os cimentos. O método FI apresentou valores de RFB estatisticamente inferiores em relação ao método FD no período de 15 min para ambos os cimentos e em 24 h apenas para o RU. Para ambos os cimentos, os valores de RFB para o método de auto-polimerização foram estatisticamente inferiores no período de 15 min em relação a 6 meses e o método FD apresentou valores de RFB estatisticamente superiores no período de 15 min em relação a 6 meses. Os valores de RFB em 6 meses foram estatisticamente inferiores em relação a 24 h nos métodos de auto-polimerização e FD para o RU. Para o VL os valores de RFB na maioria dos métodos de ativação foram estatisticamente inferiores em 6 meses em relação a 24 h. No período de 24h, o VL apresentou valores de RFB estatisticamente superiores ao RU em todos os métodos de ativação. A fotoativação foi fator essencial para a obtenção da resistência à flexão imediata (15 min) para os dois materiais. A fotoativação indireta reduziu a RFB para ambos os cimentos no período de 15 min e apenas para o RU no período de 24 h. O período de armazenamento de 6 meses, diminuiu a RFB, para a maioria dos métodos de ativação. O cimento resinoso convencional sempre apresentou valores de RFB maiores ou iguais ao cimento resinoso autoadesivo. A luz é um fator primordial para a obtenção da RFB dentro dos padrões aceitáveis, independente do período de armazenamento / Abstract: The aim of this study was to evaluate the biaxial flexural strength (RFB) of dual-cure resin cements when submitted to different activation methods and after storage periods of 15 min, 24 hours and 6 months. One hundred-twenty disk-shaped specimens for each cement (RelyX Unicem 2 automix, self-adhesive (RU) and Variolink-II, conventional (VL) were made in Teflon molds (0.5mm thickness x 6.5mm diameter) placed under controlled temperature surface (35ºC),then were polymerized as follows (n=10): self-curing method, directly light-cured (DL), light-cured with a distance of 6 mm between the light tip and the specimen (PD), and indirectly light-cured (IL) (using a 6mm composite resin barrier). Light-cured specimens were exposed for 40 seconds to visible light (56 J / cm2). Forty disc-shaped specimens by material from each storage group (15-minutes, 24 hours and 6-months) were placed into a biaxial-flexure jig and a vertical load was applied (1.27mm/min) on a universal testing machine (model 1144, Instron Corp., Norwood, MA) until failure. The original RFB values were subjected to three-way ANOVA statistical analysis and Tukey post-hoc test (p = 0.05). ANOVA revealed a significant interaction between materials, storage time and activation method (p <0.0001). RFB values for self-curing method were statistically lower compared to all other activation methods for all storage periods in both cements. The IL curing-method presented significantly lower BFS values compared with DL curing-method in 15-minutes storage time for both materials and in 24 hours just for RU. For both materials, the self-curing method presented significantly lower BFS values in the15 minutes group compared with the 6 moths group. The BFS values were statistically higher in the 15 minutes group compared with the 6 moths group when employing the DL curing-method for both cements. The BFS values were statistically lower in the 6 months group compared to 24 hours group for self-curing and DL curing-methods for RU cement. For VL cement, most methods presented statistically lower BFS values in 6 months compared to 24 hours group. The conventional dual-cure resin cement (VL) presented statistically higher BFS values compared with RU cement for all methods to 24 hours group. Light curing was essential to obtain immediate BFS values for both resin cements tested. Indirect curing method reduced BFS values in 15-minutes storage time for both resin cements and in 24 hours just for RU. Six-months storage reduced BFS values most methods. The conventional dual-cure resin cement (VL) presented higher or similar BFS values compared to self-adhesive cement (RU).Light is a key factor to obtain the RFB within acceptable standards, regardless of the storage period / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2015-07-21T15:07:51Z No. of bitstreams: 1 Ana Maria de Souza.pdf: 717565 bytes, checksum: 0b6ad0f4adba71695d0147808fdc405c (MD5) / Made available in DSpace on 2015-07-21T15:07:51Z (GMT). No. of bitstreams: 1 Ana Maria de Souza.pdf: 717565 bytes, checksum: 0b6ad0f4adba71695d0147808fdc405c (MD5) Previous issue date: 2013-12-10 / The aim of the present study was to evaluate the influence of different doses of energy and uni- or multi-wave LED units on mechanical properties of composite resins. Thereunto, six experimental groups were established for each assessed resin (IPS Empress Direct - Ivoclar Vivadent , Venus - Heraeus - Kulzer , SDR - Dentsply) according to the different different amounts of energy (5J , 10J and 20J) and LED unit (bluephase 16i and bluephase G2 - Ivoclar Vivadent) . Thirty six specimens were prepared (7mm long x 2mm wide x 1mm height) from silicon matrices and were used for evaluation of mechanical properties (flexural strength and modulus of elasticity) using the three points bending test, in a universal testing machine at a speed of 0.5 mm/min until the specimens fracture. Data were tested for normality and then the two-way analysis of variance was applied and Tukey's test was used to point out differences among means, with significance level set at 5%. Thus, the results showed that the resins presented different performance by energy amounts and by the difference of the spectra of light emitted by different sources. It appears from the data presented that the factors studied in this work are directly related to the mechanical properties of resin composites. / O objetivo do presente estudo foi avaliar a influência de diferentes doses de energia e unidades LED fotoativadoras de banda estreita e com amplo espectro nas propriedades mecânicas de resinas compostas. Para isso, 6 grupos experimentais foram estabelecidos para cada resina avaliada (IPS Empress Direct – Ivoclar Vivadent, Venus – Heraeus-Kulzer, SDR - Dentsply), de acordo com as diferentes doses de energia (5J; 10J e 20J) e unidades fotoativadoras (Bluephase 16i e Bluephase G2 – Ivoclar Vivadent). Trinta e seis corpos-de-prova foram confeccionados (7mm comprimento X 2mm largura X 1mm de altura) a partir de matrizes de silicone e foram utilizados para avaliação das propriedades mecânicas (resistência à flexão e módulo de elasticidade) utilizando o teste de flexão de três pontos, em máquina de ensaio universal a uma velocidade de 0,5 mm/min até que ocorresse a fratura do corpo-de-prova. Os dados foram avaliados quanto à sua normalidade e então, aplicado a Análise de Variância a dois critérios e teste de Tukey, com nível de significância fixado em 5%. Os resultados mostraram que as resinas apresentaram comportamentos diferentes entre si tanto pelas doses de energia utilizadas quanto pela diferença dos espectros de luz emitidos pelas diferentes fontes. Conclui-se dos dados apresentados que os fatores estudados neste trabalho têm relação direta com as propriedades mecânicas dos compósitos resinosos.

A proposta desse trabalho é demonstrar a viabilidade da técnica de transiluminação com a captação de imagens digitais através de uma pastilha de resina com pinos metálicos posicionados sobre sua superfície e imagens geradas a partir de elementos dentais, também, foram realizados processamentos matemáticos com base na transformada rápida de Fourier. Para a geração das imagens foram utilizadas fontes de laser e led com comprimentos de onda que vão do visível ao infravermelho. A análise das imagens mostrou que imagens formadas com led foram superiores as imagens formadas com laser e a cor azul não apresentou contraste suficiente independente da fonte de iluminação. Os resultados mostraram que o uso de Lasers não obteve sucesso devido à difração da luz pelos pinos e à interferência entre as radiações laser, o que provocou imagens com baixa resolução. No entanto, usando a fonte de led, foi possível definir a morfologia dos pinos na resina. Como conclusão verificou-se que os efeitos ópticos de absorção e espalhamento da luz pela resina e pelo dente, a difração da luz pelos pinos e a interferência da luz coerente foram os fatores de maior influência para a análise das imagens. / The propose of this work is to demonstrate the feasibility of the technique of transillumination to capture digital images through a resin with metal pins placed on its surface and images generated from dental elements. In addition has been made on the basis of mathematical processing transformed rapidly from Fourier. For the generation of images were used sources of laser and led with a wavelength ranging from visible to infrared. The analysis of the images showed that images formed with higher led the images were formed with laser and the blue not presented sufficient contrast independent of the source of illumination. The results showed that the use of Lasers not succeeded because of diffraction of light by pins and the interference between the laser radiation, which caused images with low resolution. However, using the source of led, it was possible to define the morphology of pins in the resin. In conclusion we note that the effects of optical absorption and scattering of light by the resin and the tooth, the diffraction of light by pins and interference of light were consistent factors of greater influence for the analysis of images.

Abstract  Aim: To determine the shear bond strength of two commercially available self-adhesive resin cements on four different materials and to analyse the degree of conversion (DC) of those resin cements.  Materials and Methods: A total of 45 embedded specimens made of four different materials were prepared for the notched-edge shear bond strength test. Ten specimens each of resin composite, glass-ionomer, zirconia and 15 of human dentine. Pillars of two different self-adhesive resin cements were luted onto these specimens. Five of the dentine specimens were treated with Katana Cleaner before being luted with Panavia. A single sample from each self-adhesive resin cement was used to determine the DC using ATR-FTIR Spectroscopy. The samples were measured uncured, right after being light cured and 10 min thereafter. Results: The highest shear bond strength values were seen for RelyX, irrespective of the material tested. This difference was statistically significant. No statistically significant difference was seen between the dentine specimens pre-treated with Katana Cleaner and luted with Panavia, compared to no pre-treatment. No statistically significant differences were found regarding DC between Panavia and RelyX.  Conclusion: The bond between the dental materials and the tooth structure is extremely important for the longevity of the restoration. The bond strength of RelyX for all materials tested were 2.1 to 37.5 times higher than that for Panavia and the differences were statistically significant. Panavia had virtually no bonding to the dentine in this study which might be due to the treatment of the dentine. The differences regarding the degree of conversion between the two resin cements were not statistically significant. However, the DC 10 min after curing was 1.3 times higher than directly after curing for both resins.

There is currently an interest in optimizing the structural design to improve materials' strength to weight ratio or improve stiffness for energy absorption. As such, cellular structures are continuously studied and improved. However, it is a well-known fact in the literature that one primary mechanism of failure of a honeycomb is the formation of shear bands. The impacts of these shear bands bring many questions and unknowns, especially when the cellular structures are created with the increasingly popular manufacturing technique of 3D printing. Therefore, understanding the deformations in 3D printed honeycomb structures is necessary to explain the behavior of materials generated through new additive manufacturing techniques and further the knowledge of the deformation localization and, consequently, formations of shear bands in the deformation process of cellular structures.In the first phase of this work, samples with a unit cell regular hexagonal honeycomb format were designed and manufactured using masked-stereolithography (M-SLA). After the curing process, the samples were prepared with a paint application in the format of speckle, and DIC was realized in a compression experiment to identify and analyze the presence of high strain regions indicating the presence of shear bands. A second phase was then conducted, aiming to consider the control and manipulation of the shear band through the utilization of relief holes. The results demonstrated that adding incisions in specific parts of the polymeric honeycomb makes it possible to change its strain spread through the shear band and change its toughness.

This thesis describes the effects of climatic factors, particularly humidity and temperature on the properties of macromolecular substances, but also others, such as UV radiation, wind, water and oxygen. Furthermore, we introduce the definition and distribution of macromolecular substances. The next section describes the basic properties of dielectric materials. Much of the text is devoted to the description, production, curing, properties and utilization of epoxy resins. The last part deals with climate factors in general terms.

This thesis describes the effects of climatic factors, particularly humidity and temperature on the properties of macromolecular substances, but also others, such as UV radiation, wind, water and oxygen. Furthermore, we introduce the definition and distribution of macromolecular substances. The next section describes the basic properties of dielectric materials. Much of the text is devoted to the description, production, curing, properties and utilization of epoxy resins. The last part deals with climate factors in general terms.

This masters’s thesis study electric properties of nanocomposites based on epoxy resins, production of samples and measuring their electrical properties. In this thesis there are observed temperature dependences of the dissipation factor, relative permittivity and internal resistivity.

Objetivo: Comparar in vitro la rugosidad superficial de una resina compuesta tipo BulkFill: Aura® BulkFill (SDI) con la resina Tetric N-Ceram® BulkFill (Ivoclar Vivadent) al ser inmersas a dos bebidas rehidratantes: Sporade® y Gatorade®. Materiales y métodos: Se utilizaron 88 especímenes de resina divididos en cuatro grupos, confeccionados con una matriz metálica (10mm x 4mm). Se insertó las resinas con una espátula de resina, y se fotoactivó con la lámpara Elipar LedTM, con una intensidad de 1200 mW/cm2. Se sumergieron los especímenes en agua destilada. A las 24 horas, se midió la rugosidad con el rugosímetro Mitutoyo SJ-210P. Luego, se realizó la inmersión en bebidas rehidratantes y se midió la rugosidad final a los 7 días. Resultados: La rugosidad inicial y final de las resinas Aura® BulkFill (SDI) y Tetric N-Ceram® BulkFill (Ivoclar Vivadent) presentaron diferencias significativas después de la inmersión en bebidas rehidratantes. Para los especímenes de Aura® BulkFill (SDI) al someterla a Sporade® se encontró una media inicial de 1.20 y una media final de 1.76 y los valores para Gatorade® fueron 0.77 y 1.73. Mientras que la rugosidad superficial de Tetric N-Ceram® BulkFill (Ivoclar Vivadent) al sumergirla en Sporade® fue 0.82 y 1.55, y en Gatorade® 0.77 y 1.73. Al comparar la diferencia de la rugosidad superficial final e inicial (deltas), la resina Aura® BulkFill presentó diferencias significativas mientras que, Tetric N-Ceram® BulkFill no tuvo diferencias al sumergirlas en ambas bebidas rehidratantes. Conclusiones: Las resinas estudiadas incrementaron su rugosidad luego de ser inmersas a las bebidas mencionadas. / Objective: To compare in vitro the surface roughness of a BulkFill composite resin: Aura® BulkFill (SDI) with Tetric N-Ceram® BulkFill resin (Ivoclar Vivadent) when immersed in two rehydration drinks: Sporade® and Gatorade®. Materials and methods: 88 resin specimens divided into four groups were used, with a metal matrix (10 mm x 4 mm). The resins were inserted with a resin spatula, and photo-activated with the Elipar LedTM lamp, with an intensity of 1200 mW/cm2. The specimens were immersed in distilled water. After 24 hours, the roughness was measured with the Mitutoyo SJ-210P rugosimeter. Then, the immersion in rehydration drinks was performed and the final roughness was measured after 7 days. Results: The initial and final roughness of the resins Aura® BulkFill (SDI) and Tetric N-Ceram® BulkFill (Ivoclar Vivadent) showed significant differences after immersion in rehydration drinks. For specimens of Aura® BulkFill (SDI) when subjected to Sporade® an initial mean of 1.20 and a final average of 1.76 was found and the values for Gatorade® were 0.77 and 1.73. While the surface roughness of Tetric N-Ceram® BulkFill (Ivoclar Vivadent) when immersed in Sporade® was 0.82 and 1.55, and in Gatorade® 0.77 and 1.73. When comparing the difference of the final and initial surface roughness (deltas), the Aura® BulkFill resin showed significant differences while, Tetric N-Ceram® BulkFill did not have differences when immersing them in both rehydration drinks. Conclusions: The resins studied increased their roughness after being immersed in the aforementioned beverages. / Tesis

OBJECTIVES: The purpose of this study was to investigate the influence of saliva contamination and subsequent surface treatments on the shear bond strength of two different resin cements to zirconia. MATERIALS AND METHODS: One hundred sintered zirconia specimens were divided into two groups (n=50), one for each resin cement to be tested. Each group was divided into five sub-groups (n=10) based on the surface treatment the zirconia plates were going to receive; namely control (CL), saliva contaminated (SC), water washed (WW), Ivoclean (IC) and air abrasion (AA). In the control group, no contamination or surface treatment was performed. Specimen surfaces of the rest of the experimental groups were contaminated with saliva, and then submitted to drying with air only (SC); washed with water (WW); treated with Ivoclean cleaning paste (IC); or sandblasted with aluminum oxide particles (Al2O3) (AA). Multilink Automix (MA) and RelyX Ultimate (RU) resin cement cylinders were made and bonded to conditioned zirconia specimens using the Ultradent jig method. All bonded specimens were placed inside glass containers filled with deionized water inside an incubator at 37 °C for 24 h. After 24 h, the shear bond strength of the bonded specimens was tested using an Instron Universal Testing Machine with a crosshead speed of 0.5 mm/minutes. Statistical analysis was performed by ANOVA and data were analyzed with Tukey-Kramer HSD multiple comparison tests at the 0.05 level of significance. RESULTS: Within the limitations of this in vitro study, it was determined that saliva contamination significantly reduced resin bond strengths to zirconia ceramic. Airborne-particle abrasion was the most effective cleaning and surface treatment. It significantly increased the shear bond strength of (MA) (13.73 ± 1.39 MPa) and (RU) (6.34± 0.8 MPa). The IC was effective in removing saliva contamination and enhancing the resin bond strength of (MA) (10.9 ± 1.28 MPa) and (RU) (3.1± 0.16MPa). Water did not remove saliva contamination and did not improve (RU) bond strength to zirconia (1.73 ± 0.25 MPa). There was no significant difference (p>0.05) between the shear bond strengths of (MA), water washing (4.7± 0.64 MPa), and control groups (4.9± 0.27 MPa). CONCLUSIONS: If contamination occurs, a surface treatment is required to guarantee an adequate interaction between the resin cement and the zirconia surface. Airborne-particle abrasion and Ivoclean surface treatments are effective in removing saliva contamination and enhancing the resin bond strength. Washing with water alone did not improve resin bond strength.