Efeito da complementação térmica de polimerização sobre a resistência flexural e dureza de resinas acrílicas para reembasamento
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Data
2003-02-25
Autores
Seó, Rosangela Seiko [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O procedimento de reembasamento da prótese é normalmente utilizado para restabelecer a adaptação entre a prótese e o tecido bucal. As resinas autopolimerizáveis são um dos materiais indicados para o reembasamento. No entanto, tem sido demonstrado que, após a polimerização das resinas autopolimerizáveis, nem todo o monômero é convertido em polímero e esse monômero residual pode afetar as propriedades mecânicas desses materiais. Estudos têm sugerido que o conteúdo de monômero residual pode ser reduzido pela irradiação em microondas ou tratamento em banho de água. Esse estudo avaliou o efeito dos tratamentos térmicos sobre a resistência à flexão e dureza Vickers de quatro resinas autopolimerizáveis para reembasamento (Duraliner II - D, Kooliner-K, Tokuso Rebase Fast - TR e Ufi Gel Hard - UGH) e uma resina termopolimerizável (Lucitone 550 - L). Para cada material, trinta corpos-de-prova foram confeccionados e igualmente divididos em três grupos. No grupo controle, os corpos-de-prova foram submetidos ao teste de resistência à flexão imediatamente após sua polimerização. Previamente ao teste, os grupos 2 e 3 foram submetidos ao tratamentos complementares em banho de água e irradiação por microondas, respectivamente. Os corpos-de-prova do material para base de prótese foram armazenados em água por 48 horas a 37o l 1oC previamente ao teste. As medidas de força foram realizadas em máquina de ensaio universal MTS 810 com uma velocidade de 5 mm/min, utilizando o teste em três pontos a uma distância de 50 mm entre os apoios. Em seguida, um dos fragmentos do corpo-de-prova foi submetido ao teste de dureza Vickers. Os valores de dureza foram determinados utilizando-se uma carga de 25 gf (resinas K, TR, L e UGH) e 10 gf para a resina D, após 30 segundos de contato. Doze mensurações de dureza foram realizadas em cada corpo-de-prova e...
To maintain the prosthesis-tissue relationship, denture base reline procedure is commonly required. Autopolymerizing resins are one of the materials indicated for relining. It has been shown that, after polymerization, not all the monomer is converted to polymer in autopolymerizing resins and this residual monomer could detrimentally affect the mechanical properties of the materials. It has been suggested that the residual monomer could be decreased by microwave irradiation or water bath heat-treatments. This study investigated the effect of heat treatments on the flexural strength and Vickers hardness of four autopolymerizing reline resins (Duraliner II - D, Kooliner-K, Tokuso Rebase Fast-TR and Ufi Gel Hard-UGH) and one heat-polymerized resin (Lucitone 550-L). For each material, 30 specimens were made and equally divided into three groups. In control group, the specimens were submitted to the flexural strength test immediately after polymerization. Before testing, groups 2 and 3 were submitted to water bath and microwave post-cure treatments, respectively. The denture base material specimens were stored in water for 48 h at 37o l 1oC before they were bend-tested. Force measurements were made with a testing machine MTS 810 at a crosshead speed of 5 mm/min using a three-point bending fixture with a span of 50 mm. Thereafter, one fragment of specimen was submitted to Vickers microhardness test. The values were determined by using a 25 gf load (resins K, TR, UGH and L) and 10 gf for resin D, after 30 s contact. Twelve hardness measurements were taken on each specimen and the average was then calculated. Kruskal-Wallis non-parametric test was used for determination of statistical significance (p<0.01). The results demonstrated that: compared to the control groups, the flexural strength of TR and...(Complete abstract, click electronic access below)
To maintain the prosthesis-tissue relationship, denture base reline procedure is commonly required. Autopolymerizing resins are one of the materials indicated for relining. It has been shown that, after polymerization, not all the monomer is converted to polymer in autopolymerizing resins and this residual monomer could detrimentally affect the mechanical properties of the materials. It has been suggested that the residual monomer could be decreased by microwave irradiation or water bath heat-treatments. This study investigated the effect of heat treatments on the flexural strength and Vickers hardness of four autopolymerizing reline resins (Duraliner II - D, Kooliner-K, Tokuso Rebase Fast-TR and Ufi Gel Hard-UGH) and one heat-polymerized resin (Lucitone 550-L). For each material, 30 specimens were made and equally divided into three groups. In control group, the specimens were submitted to the flexural strength test immediately after polymerization. Before testing, groups 2 and 3 were submitted to water bath and microwave post-cure treatments, respectively. The denture base material specimens were stored in water for 48 h at 37o l 1oC before they were bend-tested. Force measurements were made with a testing machine MTS 810 at a crosshead speed of 5 mm/min using a three-point bending fixture with a span of 50 mm. Thereafter, one fragment of specimen was submitted to Vickers microhardness test. The values were determined by using a 25 gf load (resins K, TR, UGH and L) and 10 gf for resin D, after 30 s contact. Twelve hardness measurements were taken on each specimen and the average was then calculated. Kruskal-Wallis non-parametric test was used for determination of statistical significance (p<0.01). The results demonstrated that: compared to the control groups, the flexural strength of TR and...(Complete abstract, click electronic access below)
Descrição
Palavras-chave
Resinas acrilicas dentarias, Prótese dentária, Acrylic resins, Hardness, Flexural strength
Como citar
SEÓ, Rosangela Seiko. Efeito da complementação térmica de polimerização sobre a resistência flexural e dureza de resinas acrílicas para reembasamento. 2003. 177 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2003.