Effect of dried plaster by microwave energy during polymerization procedure of heat cured acrylic resin

• Grant number: 11/19812-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2012
• End date: April 30, 2013
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Tarcisio Jose de Arruda Paes Junior
• Grantee: Camila Della Méa Vianna
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

The aim of this study is to verify the influence of a previously dried plaster by microwave energy when used in the processing method of heat-cured acrylic resin in some properties like porosity and microhardness. A heat-activated by microwave energy denture base acrylic resin VipiWave and a thermal cured in water bath acrylic resin Lucitone 550 will be used. The following groups will be formed: Group 1A - Lucitone 550, microwave polymerization, untreated gypsum; Group 1B - Lucitone 550, microwave polymerization, with treated gypsum (dried plaster); Group 2A - VipiWave, microwave polymerization, untreated gypsum; Group 2B - VipiWave, microwave polymerization, with treated gypsum (dried plaster); Group 3 -Lucitone 550-conventional heat-cured in a water bath. Every analysis will be made by use of a standard metallic cubical shaped specimens with following dimensions: 2,0x2,0x2,0cm (8cm3), 2,0x2,0x1,0(4cm3) and 2,0x2,0x0,5(2cm3). Wax in the same dimensions as metallic specimens will be confectioned and molded in reinforced glass fiber flasks. After one hour the wax specimens will be removed from flasks and then the plaster will be dry by microwave treatment (10min and 600W) for 1B and 2B groups. The flasks will be maintained in a dry oven and then the polymerization method will be executed. After the polymerization procedure, the specimens will be polished. Each group (n=10) will be stored in distilled water (37ºC and 48hours). Microhardness analysis will be established by the Vickers test (VHN), where three indentations in each specimen (single side) and values will be computed. A porosity evaluation ranking test will be made and then some specimens will be checked by a high-resolution optical microscopic (50X). Dates will be computed and submitted to statistical analysis.(AU)