Alternating current cold plasma induced surface modification of heat curing acrylic resin and prevention of early adherence of Candida albicans

Heat curing acrylic resin is an important kind of material in the prosthetic dentistry, which has been widely used in dentar e base, and the oral cavity is colonized with Candida albicans among approximately 75% of persons with dentures. In this study, alternating-current (AC) atmospheric-pressure Ar/O2 (2%) cold plasma was applied to treat the surface of th e heating curing acrylic resin, then the changes of the physica l properties and the early adherence of Candida albicans were observed. After AC plasma treatment, the surf ace hydrophilicity improved significantly. Besides, there wer e no significant differences in roughness, flexuaral strength a nd modulus of elasticity before and after AC plasma treatmen t. But interestedly, it was observed that Vickers microhardnes s had significant improvement after plasma treatment, and it was believed helpful for anti-etching ability. The early adhere nce of Candida albicans reduced after treatment. X-ray photo electron spectroscopy (XPS) and optical emission spectrum (OES) were employed to study the mechanism. After AC plas ma treatment, the C and O proportion reduced significantly, a nd new groups C-OH and -CF3 were generated on the surfac e. Actually, there existed plenty of .OH in the plasma compo nents according to the OES result. C-OH was the hydrophilic group that might lead to the improvement of surface wettabili ty. Since -CF3 is a polar group, it may be related to the adhesi on mechanism of Candida albicans. It is believed that AC no n-thermal atmospheric pressure plasma with Ar/O2 as workin g gas can provide a valuable tool for improving the wettabilit y of heat curing acrylic resin and preventing early adherence of Candida albicans, which will contribute to potential dental applications.