Efeito de tratamentos pós-polimerização sobre o peso molecular, o grau de conversão, a temperatura de transição vítrea e a liberaçãp in vitro de monômero residual, plastificante e produtos de degradação de resinas acrílicas para reembasamento imediato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação in vitro da biocompatibilidade de resinas acrílicas para base de próteses e materiais reembasadores resilientes

Pós-graduação em Reabilitação Oral - FOAR

Malha de nylon modificada para reforço estrutural de próteses odontológicas e processo de obtenção

The invention of a modified nylon mesh for structural reinforcement of dental prostheses is described, said modified nylon mesh comprising polyamide fibres and 0.3%-0.5% v/v silicon dioxide (SiO2), which enables chemical binding between the acrylic resin and the polyamide mesh in order to increase the strength of the resin/polyamide complex in said dental prosthesis.

Processo e equipamento de determinacão de desgaste de resinas compostas

Processo e equipamento de determinacão de desgaste de resinas compostas. O primeiro compreendido pelas etapas de: revestir uma superfície fixa com a resina a ser analisada, definindo uma camada superficial de resina a ser submetida a pressão dinâmica...

Influência do tratamento de superfície na infiltração marginal de reparos em porcelana

Pós-graduação em Odontologia Restauradora - ICT

Análise química, microestrutural, determinação das propriedades mecânicas e dureza de ligas odontológicas (Ag Pd,Co Cr e NiCr) fundidas em diferentes temperaturas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determinação da resistência à flexão de ligas odontológicas, utilizadas em prótese parcial fixa e prótese sobre implante, soldadas por brasagem e a laser

Pós-graduação em Odontologia Restauradora - ICT

Estudo da infiltração marginal em restaurações de resinas compostas para dentes posteriores: efeito de material, preparo cavitário e condicionamento do esmalte a nível cervical

Pós-graduação em Odontologia Restauradora - ICT

Estudo da dureza e da resistência à compressão de resinas compostas para dentes posteriores após a imersão em água destilada. Efeito da aplicação de selante superficial

Novos compósitos têm surgido no mercado especificamente destinados à confecção de restaurações estéticas posteriores. Entretanto, embora tais materiais apresentem resultados iniciais animadores, há a necessidade de comprovações adicionais para que possam ser utilizados com segurança. Resinas compostas posteriores são submetidas a estresses complexos de compressão e abrasão durante a mastigação e a aplicação de selantes superficiais tem sido relatada como forma de aumentar a resistência ao desgaste destes materiais. O presente trabalho teve como propósito avaliar a dureza e a resistência à compressão das resinas compostas Alert (Jeneric/Pentron), Ariston (Vivadent), Definite (Degussa), P60 (3M), Solitarie (Kulzer), Surefil (Dentsply) e Z100 (3M) após 90 dias de imersão em água destilada, recobertas com selante Protect It (Jeneric/Pentron) e submetidas à ciclagem mecânica (10.000 ciclos, 600N, 5Hz). Os ensaios de dureza (n=8) foram realizados em aparelho Wolpert, com diamante Vickers e peso de 50gf aplicado por 30 segundos, antes e após períodos de imersão de 30, 60 e 90 dias. Os ensaios de resistência à compressão (n=8) foram realizados somente após 90 dias, em corpos-de-prova cilíndricos medindo 8mm de altura por 4mm de diâmetro. Apenas os espécimes destinados à compressão foram ciclados mecanicamente. Os ensaios foram realizados em máquina MTS 810, equipada com célula de carga de 10kN (ciclagem) e 100kN (compressão) e velocidade de 0,5mm/min. Após análise de variância (p<0,05), os resultados mostraram, previamente à imersão, maiores valores de dureza para os materiais Z100 (74,253VHN) e Ariston (71,308VHN). A seguir, com valor semelhante à resina Ariston, mas inferior à resina Z100, apresentou-se o material Surefil (69,969VHN)...(Resumo completo, clicar acesso eletrônico abaixo)

Estudo das características térmicas e mecânicas de formulações de adesivos PSA HOT MELT contendo variações de borrachas SBC e resinas taquificantes

The properties of the hot melt adhesive pressure sensitive (HMPSA) using an elastomer as a base polymer a copolymer of styrene and butadiene (SBS) and variation of tackifiers resins such as hydrocarbon resins and hydrogenated hydrocarbon were investigated. The formulations were prepared by mixing process within shear. The adhesives prepared were evaluated in test Brookfield viscosity and softening point Ring and Ball to compare the formulations and the influence of variations in raw materials. Infrared analyzes were performed to detect the reactions between the inputs and investigate the chemical interactions of the same properties of the adhesive. In thermal analysis, the assay was performed thermogravimetry (TG) and diferencial exploratory calorimetry (DSC). Were investigated the parameters of the tensile test on each of the formulations. Finally, were analysed comparatively the basic formulations of adhesives with their respective raw materials

Eficiência das resinas XAD4 e C18 na extração de compostos mutagênicos presentes em efluente de refinaria de petróleo para a realização do Teste de Ames

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Estudo da influência das resinas termofixas uréia formaldeído (UF) e melamina formaldeído (MF) nas características físicas e mecânicas de painéis MDF

Thermosetting resins are very important in the production of MDF panels. They act as an adhesive in the process of compacting and consolidating the fiberboard. Thermoset resins commonly used in this process are based resin urea formaldehyde (UF) and melamine formaldehyde (MF). The first has a higher demand due to its low cost and good performance in meeting the specifications and standards. The second has a high cost compared to MF resin, but adds greater value to the MDF panel, because it gives greater moisture resistance. The process of manufacture of MDF boards was briefly presented in this study to facilitate the understanding of the work. Samples of thermosetting resins (UF and MF) were subjected to physical-chemical seeking to relate these results to the technological performance presented by their respective samples of MDF boards. Two other samples of MDF panels were subjected to physical and mechanical tests. Results were analyzed and related to the award of their respective thermoset resin. Instruments like Dahmos Trend Manager ® and Grecon Dax 5000 and TG - DSC analysis were used in this study to assist in the analysis of the results. It was observed that the results of the analysis of thermosetting resins were within the specified. Such resins do not directly influence the technological tests provided by the MDF panels, but it has been found that the process variables such as humidity and fiber production rate interfere with the performance of the resin accelerating the reaction and therefore their influence on the physical-mechanical properties of the panels MDF. Samples of MDF panels with UF and MF met all the specifications required by the Brazilian standard with regard to the technological quality. The increased demand for UF resin market is justified by the service specifications...

Contaminación microbiana en las líneas de agua de las unidades odontológicas

Introduction and Objective: Microorganisms are responsible for multiple infections and pathologies; this is why it is important to control microbes that can be found in the triple syringe used for irrigation in different dental procedures. The aim of this study was to identify cultivable species of microbes (fungus and bacteria) found in some dental units water lines of a private dental clinic from Medellín, Colombia. Materials and Methods: Random samples were taken from 11 chairs from a total of 89; a sample of water of 500ml was collected from the triple syringe of each selected chair. The study aim to search for the presence of total coliforms, filamentous fungi and leavened Results: the average presence of microorganisms was between 40CFU and more of 200 CFU. Microorganisms such as Aeromona salmonicida, Actinobacilus sp and Pseudomona maltophil were isolated. No total coliforms neither fecal coliforms were found. Conclusions: the high levels of contamination suggest that there is a mature biofilm in somewhere of the dental unit water line, but the absence of total and fecalis coliforms suggest that the water had been treated.

Efeito de fontes de luz na microdureza de resinas compostas

This study assessed the surface microhardness of compound resins cured by different light sources. Methods Three micro hybrid (Vit-l-escence, Amelogen Plus, Opallis) and one nanoparticle (Filtek Z350, 3M ESPETM Dental Products, St. Paul, USA) compound resins were selected. The resins were polymerized by a halogen light unit (Ultralux, Dabi Atlante, Ribeirão Preto, Brasil) with two tips, one semi-guided made of glass and another of painted acrylic and a LED-based source (UltraLume 2, Ultradent®, South Jordan, USA). Specimens constructed from a circular aluminum matrix were photopolymerized for 40 second after they received the compound resin and stored dry for 24 hours. After this period, a Vickers surface microhardness assay was performed, measuring the top (hardness 1) and base (hardness 2) surfaces four times each. Variance analyses were complemented by Newman-Keuls method, with significance set at 5%. Results The Opallis (FGM, Santa Catarina, Brasil) resin subjected to UltraLume 2 (Ultradent®, South Jordan, USA) obtained the lowest mean hardness values for the top surface. The Vit-l-escence (Ultradent®, South Jordan, USA) compound cured by Led UltraLume 2 (Ultradent®, South Jordan, USA) and by Ultralux PCP (Dabi Atlante, Ribeirão Preto, Brasil) halogen light obtained the highest mean hardness, followed by the Filtek Z350 (3M ESPETM Dental Products, St. Paul, USA) resin subjected to UltraLume 2 (Ultradent® South Jordan, USA). The Opallis (FGM, Santa Catarina, Brasil) resin cured by LED UltraLume 2 (Ultradent®, South Jordan, USA) also obtained the lowest mean hardness for the base surface and the Vit-L-Escence (Ultradent®, South Jordan, USA) resin obtained the highest value, followed by Amelogen Plus, when cured by Ultralux (Dabi Atlante, Ribeirão Preto, Brasil) using the semi-guided tip. Conclusion The polymerization and, consequently, the microhardness achieved by the LED unit was equivalent to those achieved by conventional halogen units for three of the four composites tested.

Análise comparativa da rugosidade superficial de resinas compostas de alta densidade

The success achieved by the use of composite resins in anterior teeth precipitately leads their use in posterior teeth. However, the indiscriminate application of these materials in cavities with several diverse sizes rapidly pointed out their lack of resistance to oclusal and proximal wear. OBJECTIVE: To evaluate the surface roughness of composite resin in relation to finishing and polishing technique. MATERIAL AND METHODS: Eight experimental groups (n = 15) were divided according to finishing and polishing technique: G1 – Z250TM composite resin without surface finishing and polishing; G2 – Z250TM composite resin plus surface finishing and polishing; G3 – P60TM composite resin without surface finishing and polishing; G4 – P60TM composite resin plus surface finishing and polishing; G5 – Prodigy CondensableTM composite resin without surface finishing and polishing; G6 – Prodigy CondensableTM composite resin plus surface finishing and polishing; G7 – SurefillTM composite resin without surface finishing and polishing; G8 – SurefillTM composite resin plus surface finishing and polishing. Three packable and one microhybrid (control group) composite resin was used. The surface roughness was measured using a profilometer at three points in each sample. The results were evaluated by ANOVA and Tukey test (p < 0.05). RESULTS: Prodigy CondensableTM composite resin showed the lowest surface roughness, while SurefillTM showed the highest surface roughness. Comparing the resins used, only between P60TM and SurefillTM there were no statistically significant differences (p > 0,05). CONCLUSION: Surface roughness was lower in all types of resin composites surfaces in contact with Mylar matrix strip than in areas submitted to finishing and polishing procedure.