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paleari_ag_me_arafo.pdf: 793753 bytes, checksum: 23f0598b1ea98fd46f7b8f717a6e8c30 (MD5) === Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) === Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) === Muitas tentativas de incorporar agentes antimicrobianos a resinas acrilicas para base protetica tem sido realizadas visando prevenir inflamacoes nos tecidos orais de usuarios de proteses. Entretanto, essas substancias podem ser liberadas da resina acrilica e afetar suas propriedades mecanicas. O metacrilato 2-ter-butilaminoetilo (TBAEMA) e uma substancia policationica que pode apresentar atividade antimicrobiana a partir de grupos amina presentes em sua composicao. Objetivos: 1) investigar uma possivel uniao quimica entre o TBAEMA e a matriz de uma resina acrilica e avaliar a presenca de grupos amina na superficie dos especimes; 2) verificar os efeitos causados pela incorporacao de TBAEMA sobre a resistencia flexural e a temperatura de transicao vitrea (Tg) da resina acrilica. Material e Método: Foram confeccionados especimes a partir de uma resina acrilica termopolimerizavel (Lucitone 550) contendo diferentes concentracoes de TBAEMA (0%, 0,5%, 1%, 1,50%, 1,75% e 2%) e posteriormente foram submetidos a avaliacoes em Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Espalhamento Superficial de Eletrons com Analise Quimica (ESCA) e Calorimetria Diferencial de Varredura (DSC). A avaliacao de resistencia a flexao foi realizada de acordo com as normas ISO/FDIS 1567. Resultados: Atraves de FTIR, observou-se bandas de absorcao na regiao 1300-1320 cm-1 do espectro dos grupos de resina acrilica modificada. Diferentes indices de Nitrogenio foram observados na superficie dos especimes atraves de analises em ESCA. A Tg diminuiu de acordo com a incorporacao de TBAEMA. A resistencia a flexao foi avaliada por meio de analise de variancia a um fator (ANOVA) seguida pelo teste de Tukey (α= 0,05). Observou-se que a resistencia a flexao diminuiu significativamente apos a adicao de TBAEMA em concentracoes de 1%, 1,5%, 1,75% e 2% (p<0,05). Conclusão: Pode ser concluido que: 1) Houve evidencias... === Several attempts to incorporate antimicrobials agents into denture base resins have been reported in order to prevent inflammation of oral tissues in denture wearers. However, these substances may be released from acrylic resins and affect their mechanical properties. The 2-tertbutylaminoethyl methacrylate (TBAEMA) is a polycationic substance that may displays antimicrobial activity from pendant amino groups. Objectives: 1) to investigate the possible chemical bound of TBAEMA to the matrix of acrylic resin and to analyze the presence of amino groups on the specimen surface; 2) to evaluate the effect of the incorporation of TBAEMA on flexural strength and glass transition temperature (Tg) of an acrylic resin. Material and Methods: Specimens were prepared from a heat-polymerized acrylic resin (Lucitone 550) mixed to different concentrations of TBAEMA (0%, 0.5%, 1%, 1.50%, 1.75% and 2%) and were submitted to Fourier Transform Infrared (FTIR) Spectroscopy, Electron Spectroscopy for Chemical Analysis (ESCA) and Differential Scanning Calorimetry (DSC) analyses. Flexural strength tests were performed according to ISO/FDIS 1567 specifications. Results: FTIR analysis showed absorbance bands at 1300-1320 cm-1 in the spectrum of TBAEMA-modified acrylic resin groups. Different nitrogen ratios were observed on specimens surfaces by ESCA measurements. The Tg decreased with incorporation of TBAEMA. Flexural strength data were analyzed by one-way ANOVA followed by Tukey’s test (α= .05). The flexural strength decreased with the addition of 1%, 1.5%, 1.75% e 2% of TBAEMA (p<0.05). Conclusion: Within the limitations of this study, it may be concluded that: 1) There was an evidence of copolymerization between acrylic resin and TBAEMA and the presence of nitrogen indicate that amine groups were found on the specimens surfaces; 2) Flexural strength and glass transition temperature were affected after... (Complete abstract click electronic access below)
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