Estudo de propriedades da resina acrílica termoativada por energia de micro-ondas frente às variações nos procedimentos de inclusão

On heat cured acrylic resins by microwaves energy the action of electromagnetic waves on methylmethacrylate promote the polymerization process. However, part of this energy is absorbed by the gypsum present in the flask and the function of this gypsum is to maintain the characteristics of specimen, nevertheless is unknown in the literature as the amount of water present in this gypsum affects the characteristics of acrylic resin. The proposal of this study was verified if dried gypsum influenced in some properties of the acrylic resins thermally activated by microwaves: presence of porosity, microhardness, roughness, flexural strength and dimensional change. Two different types of acrylic resin for complete denture were utilized: Lucitone 550 e Vipi-Wave and groups were formed: Lucitone 550, polymerization by microwave energy without gypsum treatment; Lucitone 550, polymerization by microwave energy with pretreatment gypsum; Vipi-Wave by microwave energy without gypsum treatment; Vipi Wave, polymerization by microwave energy with pretreatment gypsum; Lucitone 550 control group polymerization in hot water bath. For both situations were performed analysis of microhardness and porosity three different metallic shaped specimens were formed with followed dimensions: 2,0x2,0x2,0cm (8cm3); 2,0x2,0x1,0 (4cm3) e 2,0x2,0x0,5 (2cm3). Standardized wax specimens was used to prepare groups (n=9) and included in glass fiber flasks. The gypsum dry was made by microwave oven cycle (10min and 600W) and then the flasks were maintained in dry oven during two hours. Polymerizations of specimens were made and then polished. Wax patterns #7 obtained from the metal were embedded in plastic flask and following the processes of pressing and polymerization of the resin according to established groups. To evaluate the flexural strength, specimens 65mm x 10mm x 3.0mm from metallic patterns in bar format were made. ...

Estudo comparativo in vitro da resistência à remoção de grampos circunferenciais aplicados sobre dentes íntegros e restaurados com resina composta

An experimental study was undertaken in arder to find out lhe behavior of the required force to yield dislodgement of circumierential clasps of removable partial dentures ou two groups of samples. 1 with retentive terminais engaging and acting ou enamel 2 with retentive terminais engaging on enamel and acting on composite resm With this aim a device was designed based on a sewing machine (brand name Elgin) that could repeatedly simulate lhe introduction-removal movement of circunferencial clasps ou the samples. ln addiction the device had a platform to sustain the samples and permit measurements, a cycle counter and a dynamometer. The samples were constructed by inclusion in dental stone of extracted natural molar teeth whose retentive areas were ou natural enamel or composite resin addictions.The clasps were fabricated from wax ups of resin and wax and were cast with chromium cobalt alloy. The composite resin used was one of the last generation, monomodal type, photopolymerized and binded to the enamel by the acid etching technique. Tests were carried out in aqueous enviroment. Is was established a maximum of 5.000 cycles for each of the samples. Observatins were made from 100 to 100 cycles until 2.000 and from 200 to 200 cycles to 5.000. Results showed that variations in the amount of the required force for dislodgement of the clasps from the samples during the test periods had no significancy eather to those with retentive areas on the enamel or to those with retentive fabricated with addictions of composite resin

Protese ocular individualizada em resina acrílica com esfera oca

The technique proposed aims at reducing the weight of individualized ample ocular prostheses using acrylic resins as well as simplifying laboratory procedure. For that, prefabricated hollow spheres made of plastic material, were inserted in the sclera. The average weights of the solid conventional sclera (5.30g) and those of the respective prefabricated plastic ones (3.91g) were compared. The weight reduction was significative with a confidence interval of 95% by the Student t test. ln addition, for illustration purpose, the technique was applied to patients in the ward of the Maxillofacial Prostheses Dicipline of the Dentistry School in the Campus of São José dos Campos - UNESP, having each patient received a solid prosthesis and a hollow prefabricated one made of plastic material. It has been concluded that the prostheses material spheres were inserted are lighter than the ones which received solid spheres; furthermore, thr technique is viable for ample anophtalmic cavities and requires few sessions

Avaliação da termociclagem sobre a estabilidade de cor de diferentes matizes de resina composta

The objective was to evaluate the effect of thermocycling on the color variation of three different composite resins . We studied was Resin Enamel on 3 levels : ( Esthetic X , Opallis and Venus ) ; Resin Dentin in three levels : ( Esthetic X , Opallis and Venus ) and Thermocycling on level 1 : ( 3,000 cycles ) ; variable was the change of color gauged by spectrophotometry . 60 specimens , subdivided into 6 groups were made : GI - Esthetic X Enamel ; GII - Esthetic X dentin ; GIII - Opallis Enamel ; GIV - Opallis dentin ; GV - Enamel and GVI Venus - Venus dentin . The specimens were prepared with a matrix to standardize samples . The inserts of incrementally resins and polymerized with a halogen light Ultralux unit ( Dabi Atlante , Brazil ) with a power of 450mW / cm ² . After fabrication , underwent color reading with a UV Visible Spectrophotometer reflection , UV -2450 ( Shimadzu , Kyoto , Japan ) , with the changes calculated by the system CIE L * a * b * . Then isolates were stored in artificial saliva at 35 ° C ± 2 ° C during 3 months containers being subjected to the effects of thermal cycling for 3000 cycles over the range of 5C to 55C . Again subjected to chromatic evaluation. For the analysis of the results of color change of the studied resins was applied ANOVA two factors at 5 % . The results showed a statistically equal resins enamel GI and GV ( p = 0.79 ) ; the same was not observed for GI and G III resins , where the color change was higher for resin G III ( p = 0.0000002 ) . The same was observed between G III and GV , where the resin enamel G III showed a statistically superior to the color change ( p = 0.0000005 ) Average . Resins to dentin was there a statistical equality between the materials studied . We conclude that the resins studied change in color and resin enamel G III was the most suffered major color changes after aging by thermocycling .

Avaliação clínica da efetividade do clareamento de consultório sem troca do gel clareador

Esse trabalho teve como objetivo avaliar, clinicamente, a efetividade de dois agentes clareadores aplicados sobre a superfície dentária durante 45 minutos, sem troca do gel. Foram selecionados 10 pacientes de acordo com os critérios de inclusão e exclusão, e a arcada superior dos pacientes foi dividida em duas hemiarcadas (n = 10): na hemiarcada direita (HD), foi aplicado o peróxido de hidrogênio a 35% (PH) Clàriant Office (Angelus); e, na hemiarcada esquerda (HE), o PH 38% Opalescence Boost (Ultradent). Foram realizadas duas sessões clínicas, de 45 minutos cada, com intervalo de uma semana entre as sessões. Inicialmente, ao tratamento clareador, os pacientes receberam profilaxia, moldagem para guia de mensuração de cor com silicone de condensação e avaliação de cor por meio de um aparelho espectrofotômetro Vita Easyshade (Vita Zhanfabrik, Alemanha). Após 14 dias do término do tratamento clareador, foi realizada a mensuração final da cor dos dentes. Os dados foram submetidos ao teste t e de Tukey (p < 0,05). Os resultados demonstraram não haver diferença estatisticamente significativa entre as hemiarcadas quanto à efetividade do clareamento (p = 0,146) e nem quanto à sensibilidade. Pode-se concluir que a aplicação dos materiais avaliados sem troca do gel, por 45 minutos, foi eficaz em promover o clareamento de dentes vitais e com baixa sensibilidade dentária.

Fechamento de diastemas utilizando restaurações diretas de resina composta

Os diastemas contribuem para a quebra de harmonia dos dentes, comprometendo a beleza do sorriso; os incisivos superiores são os dentes que mais se destacam no sorriso, sendo muito importante a simetria e harmonia entre eles. Para o fechamento dos diastemas, durante muito tempo, as alternativas clínicas foram o emprego da Ortodontia e das próteses fixas. Atualmente, com a evolução dos sistemas adesivos e das resinas compostas, é possível reproduzir as características dos dentes com uma técnica simples, previsível, sem desgaste da estrutura dentária, reversível, com menor custo, proporcionando um resultado satisfatório e imediato. O propósito do presente artigo é apresentar três casos clínicos de fechamento de diastemas generalizados associados ou não a outras alterações que comprometem o sorriso do paciente.

Estudo clínico retrospectivo de restaurações cerâmicas do tipo laminado sobre dentes com ou sem preparo dentário: 1 a 5 anos de acompanhamento

Pós-graduação em Odontologia - FOA

Caracterização e reciclagem química via pirólise de resíduos da fabricação de pás eólicas

A energia eólica é uma forma de energia que seu uso encontra-se em expansão, e junto a esse crescimento, tem-se também o aumento da quantidade de resíduos gerados na fabricação das pás eólicas. Uma forma correta de destinação e aproveitamento desses resíduos é a reciclagem. Porém, esses são constituídos de materiais compósitos, geralmente a resina epóxi e a fibra de vidro; e por possuírem um polímero termofixo (a resina epóxi) na sua composição, a reciclagem convencional via fusão não é possível. Desta forma, a reciclagem química via pirólise apresenta-se como uma alternativa para o aproveitamento desses resíduos, em especial da fibra de vidro que o contém. Após caracterização do resíduo de uma indústria de pás eólicas, verificou-se que se tratava de um material com mais de 70% de fibra de vidro e muito densas. Foram realizados ensaios de pirólise a seco e com óleo de babaçu, considerado o mais interessante perante vários possíveis e no qual o resíduo fica totalmente imerso, facilitando o inchamento e a troca de calor. Em um sistema de aquecimento com vácuo, foram obtidas mais de 97% de fibras em 30 minutos a 310 oC, justamente a temperatura em que uma análise termogravimétrica apontou ser a de início de altas taxas de degradação térmica.

Avaliação da resistência de união da resina composta ao esmalte desmineralizado submetido à remineralização e infiltração resinosa de lesão de cárie

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

Propriedades físicas, químicas, antimicrobianas e biológicas de cimentos endodônticos com óxido de cálcio e resina salicilato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência de união de reparos em resinas compostas convencionais e bulkfill

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de vanádio em águas usando a técnica de difusão em filmes finos por gradientes de concentração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Redução de tempos de setup: aplicação de troca rápida de ferramentas em indústria de bebidas

The current competitive market requires companies to adapt so that they can meet the needs of customers in an agile manner and aimed at the lowest possible cost in their manufacture, be it a product or service. The Toyota Production System is aimed at higher profits through lean manufacturing practices with reduced spending, smaller lots and inventories, generated by market demand. The variety of products makes the setup of the equipment a critical point and it should be reduced as much as possible so it does not affect productivity. The rapid exchange of tools allows with few actions and a modification that time does not exceed one digit on your total time. In this study, a case study showed that only with standardization and use of cheap improvements made it possible to reduce setup time in bottle labeling machine by 98 minutes for a final time of approximately 10 minutes with little investment, demonstrating the feasibility the displayed and a monthly gain tool in bottles at approximately 120,000, generating a performance gain and budget of approximately R$ 94,000.00 per month

Estudo da cinética de degradação da resina benzoxazina e seus compósitos nanoestruturados

The benzoxaxine resin is a new class of thermoset phenolic resin, which is presenting, in the lasts decades, a great application in the aircraft industry due mainly to its excellent mechanical and thermal properties. This resin associates the mechanical properties of epoxy resin with the thermal and flame retardant properties of phenolic resin. In this context, they are considered polymers of high performance and they are excellent candidates to replace the current thermoset matrices used in the processing of high performance composites. Thus, in this study nanostructured composites Benzoxazine/CNT were produced at different concentrations of functionalized and non-functionalized CNT (0,1%; 0,5% and 1,0% w/w). The thermal stability of the benzoxazine resin and its nanostructured composites was studied using thermogravimetry (TGA) and degradation kinetic model Ozawa-Wall-Flynn (O-W-F). The thermal characterization also included differential scanning calorimetry (DSC) and dynamic-mechanical analysis, infrared spectroscopy with Fourier transform (FTIR) and scanning electron microscopy (SEM).The introduction of non-functionalized CNT at low concentrations resulted in nanostructured composites with better thermal properties in relation to the neat resin. For all cases, however, the dispersion of CNT in the matrix was ineffective