Amer A. Taqa
To evaluate the influence of curing methods and temperatures as variables of water sorption, water solubility and present porosity in poly methyl methacrylate (PMMA) denture bases. The effect of autoclave processing on these properties has not been fully determined. The effect of autoclave on acrylic powder has not studied before. Vertex was the heat – cured acrylic denture base material included in this study. A total of 120 specimens were prepared, the specimens were grouped into three control groups of Vertex acrylic resin which (group A) as curing by conventional water- bath technique (74C° for 90 minutes then boil for 30 minutes), (group B) which curing by water- bath (100C° for 30 minutes), and (group C) which curing by autoclave (120 °C under 1.4 bar for 45 minutes). The other three groups of Vertex acrylic resin after treatment of powder by autoclave in 132 °C for 4 hours, and then grouped into (A1, B1 and C1) which curing as previously. To study the effect of treatment of powder of acrylic resin by autoclave and the effect of autoclave processing. Three tests were conducted, water sorption and solubility tests, and the mean percent porosity (Electronic sensitive balance sensitive to 0.0001 g). The results were analysed to Descriptive Statistics and ANOVA test. There was a significant difference in water sorption test results in all studying groups. There was a non-significant difference in water solubility test results between studying groups. There was nonsignificant difference in present porosity test results between studying groups. The treatment of powder of acrylic resin by autoclave had a significant difference on water sorption, but had a nonsignificant difference on water solubility and percent porosity test in all test results. The autoclave processing technique might also be a good alternative to the conventional water- bath processing technique.
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