RESUMO
A total of 62 disk-shaped specimens in the size of 30 mm (diameter) ×2 mm (layer thickness) were made with auto-polymerized acrylic resin (2 specimens for infrared spectrum comparison and 60 specimens for tests of water sorption and solubility). Duration of Ar plasma application was 2 minutes and plasma power applied was 60 W. Storage intervals were 1 day, 1 week, 1 month, 6 months, and 12 months, separately. A control group and a corresponding experimental group were set for each storage interval, with 6 specimens per group. All specimens were weighted 3 times, i.e., initial weight; weigh after absorption of distilled water, and final weight after desiccation. Percentages of water absorption and solubility of auto-polymefized acrylic resin were calculated. Results revealed that after Ar plasma treatment, C-H structure of auto-polymerized acrylic resin was reduced; following 1-month storage interval, water absorption percentage was significantly lower in the experimental group than in the control group; following 1-day, 1-week, and 1-month storage interval, the experimental group exhibited significantly lower solubility of auto-polymerized acrylic resin, compared to the control group (P<0.05). These results indicated that within 1-month storage, Ar plasma treatment can decrease water sorption and solubility of auto-polymerized acrylic resin.