Avaliação in vitro da efetividade de polimerização da resina acrilica dental polimerizada atraves de energia de microondas, quando em contato com metal

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

The conventional method to process acrylic resin is a time consuming step to construct removable prosthodontics. The microwave processing would be a solution,. but there are doubts about this process in metal presence. So the aim of this study was to compare residual monomer, microhardness and porosity of two acrylic resin cured by different methodos in the presence of a metal ftamework. The conditions evaluated were: Group 1- Acrylic resin c1assico, short heatcured for 3 h, Group 2- Acron M-C resin cured in microwave for 3 min at 500 W, Group 3- Acrylic resin c1assico cured in microwave for 3 min at 500 W. For each group 12 specimens measured 30 x 4 mm( diameter x thickness) and contained in the inner a metal ftamework (28 x 10 mm). After the cure the samples were imersed individually in 6,5 m1 of deionized water. Residual monomer released in the water, changed dai1y, was measured spectrophotometricalIy for 12 days. The specimes were . polished to measure the microhardness ftom 50 to 800 ~m of the metal ftamework. The specimes were cross-sectioned to evaluate the internal and external porosity by naked eye and using 100 x magnification. The results (mean ::!: SE ) of monomer release ( % x 10-4) and microhardness for the three groups were respectively: Day 1st 178,8 ::!: 17,9 A, 59,5::!: 11,1 B,116,5 ::!: 12,0 C; 12 th 44,3 ::!: 2,2 A, 6,8 ::!: 1,3 B, 40,1 ::!: 2,7 A. The Knoop hardness were 1)50 ~m 16, 45 ::!: 0,22 B , 17,46 ::!: 0,20 A, 17,14 ::!: 0,26 AB; 2) 800 ~m 16,75 ::!: 0,14 B 18,14 ::!: 0,32 A, 17,55 ::!: 0,22 A . Statistical analysis ( ANOV A) Showed , I difference among the groups and means folIowed by the same lether do not differ significantly (Tukey, p<ü,05 % ). Porosity by naked eye was observed in alI the samples ftom group 3 and in 50% of the group 1 and 2 . Using magnification, porosity was found externalIy and interalIy in alI samples. It was conc1uded that the microwave energy can be effectively use to polimerized removable partial denture bases and the conventional resin when polymerized with microwave energy presented higher porosity

ASSUNTO(S)

porosidade microondas resinas dentarias manometro

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