Efeito do tempo pos-prensagem sobre a rugosidade, dureza e porosidade superficial da resina acrilica QC 20, em diferentes ciclos de polimerização

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The purpuse of this study was to investigate the effect of post-pressing step time on the roughness, surface hardness Knoop and porosity of a QC-20 acrylic resin in different polymerization cycles. Specimens were manufactured using 30 mm high and 5 mm thick round condensation silicone matrices, obtained through a standard method. The matrices were placed in metallic and in fiberglass-reinforced mufles. Powderlliquid ratio and acrylic resin pressing were carried as recommended by the manufacturer. Mufles were allowed to rest in the 0011 press for 30 minutes, 12 and 24 hours before being polymerized in heated water, boiling water and microwave energy cycles at 74°C for 9 hours. Afier cooling in room temperature, specimens were fmished and polished with politriz. Afterwords, specimens were submitted to superficial roughness test, using roughness tester Surfcorder SE 1700; to a superficial hardness test in a microdurometer Shimadzu 2000, and apparent porosity in which specimens were immersed in Nankin ink for 8 hours, being sectioned in a determined area later. The results were submitted to variance analysis and Tukey s test 5% significance leveI. 1t was concluded that there were no significant differences between the averages obtained by the methods used for roughness and porosity. For superficial hardness, there were significant differences between the conventional method and the other two used, showing that the conventional method demonstrated less hardness when compared to the others

ASSUNTO(S)

materiais dentarios protese dentaria completa resinas dentarias

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