Made available in DSpace on 2014-06-11T19:24:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-02-19Bitstream added on 2014-06-13T20:12:03Z : No. of bitstreams: 1 alencarjunior_ea_me_arafo_prot.pdf: 747787 bytes, checksum: fd32e276778e87934566a313af1035b5 (MD5) / O objetivo desta pesquisa foi avaliar a influência da distância de uma fonte de luz halógena na microdureza superficial da resina composta, considerando as superfícies de topo e base dos corpos-de-prova. Foram utilizadas duas marcas comerciais de resina composta, Z250 de partículas pequenas e uma resina de micropartícula, A110, ambas da 3M do Brasil Ltda. O aparelho de ativação da resina composta foi K&M 220- R, cuja intensidade de luz possui um pulso que variava após os 5 primeiros segundos assim alcançando sua intensidade máxima que foi medida em 720 mW/cm2. Para a determinação da intensidade de luz emitida pelo aparelho fotoativador, utilizou-se um radiômetro (Medidor de irradiância 150- CMC , São Carlos - SP). Corpos-de-prova foram confeccionados utilizado-se matrizes metálicas que possuíam um orifício central de 4mm de diâmetro por 2mm de espessura. As resinas foram inseridas no orifício da matriz metálica, em um único incremento, por meio de uma espátula metálica e sobre elas foi sobreposta uma tira matriz transparente de poliéster e, após isto, um peso de 1 Kg foi posto em cima da tira para que houvesse uma melhor condensação da resina composta evitando a presença de bolhas de ar, no interior do corpo-de-prova. A fonte de luz halógena foi fixada em uma mesa de maneira que a saída da ponta de luz ficasse paralela à superfície do corpo-de-prova. Para provocar o distanciamento da fonte de luz, anéis metálicos confeccionados em latão, com espessuras que variavam de 2mm, 4mm e 8mm foram utilizados, os quais, após posicionados, eram removidos para não interferiem no dispersamento da luz. As distâncias imprimidas a fonte de luz na superfície da resina foram de 0mm(tocando a superfície), 2mm, 4mm e 8mm. Para cada uma destas distâncias, a intensidade de luz foi medida. Esta variou de intensidade de... . / The aim of this research was to evaluate the influence of the light tip distance in the superficial microhardness of the composite resin, considering the surfaces of top and base of the samples. Two commercial composite resin marks had been used, Z250 of small particles e a microparticle resin, A110, both of 3m of Brazil Ltda. The device of activation of the composite resin was K&M 220- R, whose intensity of light possess a pulse that varied the 5 first seconds after thus reaching its maximum intensity that was measured in 720 mW/cm2. For the determination of the intensity of light emitted for the fotoativador device, a radiometer (Measuring of irradiance 150- CMC was used, Is Carlos. SP). The samples had been confectioned used first metallic that had a central orifice of 4mm of diameter for 2mm of thickness. The resins had been inserted in the orifice of the metallic array, in an only increment, by means of a metallic spatula and on them a transparent first polyester strap was overlapped and, after this, one weight of 1 kg was rank in top of the strap so that it had one better condensation of the composite resin preventing the presence of air bubbles, in the inward of the body-of-test. The source of light was fixed in a table thus the output of the light tip was parallel to the surface of the body-of-test. To provoke distance from the light source, confectioned metallic rings in brass, with thickness that varied of 2mm, 4mm and 8mm had been used, which, after located, was removed to avoid concentration of light. The printed pitches the source of light in the surface of the resin had been of 0mm(on the surface), 2mm, 4mm and 8mm. For each one of these pitches, the light intensity was measured. This varied of intensity of 720 mW/cm2 for the tip touching the surface of the body-of-test, 650 mW/cm2 for in the distance of 2mm, 600 mW/cm2... (Complete abstract, click electronic address below).

Orientador: Marcelo Ferrarezi de Andrade / Banca: José Roberto Cury Saad / Banca: Mânio de Carvalho Tibúrcio / Resumo: O objetivo desta pesquisa foi avaliar a influência da distância de uma fonte de luz halógena na microdureza superficial da resina composta, considerando as superfícies de topo e base dos corpos-de-prova. Foram utilizadas duas marcas comerciais de resina composta, Z250 de partículas pequenas e uma resina de micropartícula, A110, ambas da 3M do Brasil Ltda. O aparelho de ativação da resina composta foi K&M 220- R, cuja intensidade de luz possui um pulso que variava após os 5 primeiros segundos assim alcançando sua intensidade máxima que foi medida em 720 mW/cm2. Para a determinação da intensidade de luz emitida pelo aparelho fotoativador, utilizou-se um radiômetro (Medidor de irradiância 150- CMC , São Carlos - SP). Corpos-de-prova foram confeccionados utilizado-se matrizes metálicas que possuíam um orifício central de 4mm de diâmetro por 2mm de espessura. As resinas foram inseridas no orifício da matriz metálica, em um único incremento, por meio de uma espátula metálica e sobre elas foi sobreposta uma tira matriz transparente de poliéster e, após isto, um peso de 1 Kg foi posto em cima da tira para que houvesse uma melhor condensação da resina composta evitando a presença de bolhas de ar, no interior do corpo-de-prova. A fonte de luz halógena foi fixada em uma mesa de maneira que a saída da ponta de luz ficasse paralela à superfície do corpo-de-prova. Para provocar o distanciamento da fonte de luz, anéis metálicos confeccionados em latão, com espessuras que variavam de 2mm, 4mm e 8mm foram utilizados, os quais, após posicionados, eram removidos para não interferiem no dispersamento da luz. As distâncias imprimidas a fonte de luz na superfície da resina foram de 0mm(tocando a superfície), 2mm, 4mm e 8mm. Para cada uma destas distâncias, a intensidade de luz foi medida. Esta variou de intensidade de... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: The aim of this research was to evaluate the influence of the light tip distance in the superficial microhardness of the composite resin, considering the surfaces of top and base of the samples. Two commercial composite resin marks had been used, Z250 of small particles e a microparticle resin, A110, both of 3m of Brazil Ltda. The device of activation of the composite resin was K&M 220- R, whose intensity of light possess a pulse that varied the 5 first seconds after thus reaching its maximum intensity that was measured in 720 mW/cm2. For the determination of the intensity of light emitted for the fotoativador device, a radiometer (Measuring of irradiance 150- CMC was used, Is Carlos. SP). The samples had been confectioned used first metallic that had a central orifice of 4mm of diameter for 2mm of thickness. The resins had been inserted in the orifice of the metallic array, in an only increment, by means of a metallic spatula and on them a transparent first polyester strap was overlapped and, after this, one weight of 1 kg was rank in top of the strap so that it had one better condensation of the composite resin preventing the presence of air bubbles, in the inward of the body-of-test. The source of light was fixed in a table thus the output of the light tip was parallel to the surface of the body-of-test. To provoke distance from the light source, confectioned metallic rings in brass, with thickness that varied of 2mm, 4mm and 8mm had been used, which, after located, was removed to avoid concentration of light. The printed pitches the source of light in the surface of the resin had been of 0mm(on the surface), 2mm, 4mm and 8mm. For each one of these pitches, the light intensity was measured. This varied of intensity of 720 mW/cm2 for the tip touching the surface of the body-of-test, 650 mW/cm2 for in the distance of 2mm, 600 mW/cm2... (Complete abstract, click electronic address below). / Mestre

Indiana University-Purdue University Indianapolis (IUPUI) / The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture.