Study on inactivation of planktonic Candida albicans on the surface of denture base resin

QIAO Chun-yuan; ZHANG Huai-qin

doi:10.3969/j.issn.1672-2973.2017.02.009

Abstract：Objective:To investigate the fungicidal effects of different plasma (argon,30％H2O2 and 50％H2O2 plasma) on planktonic Candida albicans on the surface of acrylic resin.Methods:Candida albicans were inoculated on polymethyl methacrylate specimens with the size of 9mm× 9mm× 2mm.Fifty-six resin specimens were randomly divided into fourteen groups (n=4).The specimens in control group did not receive any treatment and the other groups were exposed to argon,30％H2O2 and 50％H2O2 plasma for different time durations.Each specimen was immersed into phosphate bufffered saline (PBS) for 2h and sonicated for 5 min in an ultrasonic bath sonicater.PBS cell suspensions of corresponding specimens were serially diluted.Then aliquots of appropriate dilutions (200μl) were inoculated on Sabouraud dextrose agar and incubated at 37℃ for 48h before the colonies were counted.The anticandidal efficacy of plasma was evaluated by the reduction of colony forming units (CFU) in log10.Reduction of 4 log10CFU was regarded as the threshold of clinical relevance in accordance with EN 1275-2005.Results:The reduction of viable Candida albicans on the resin was 4.016 log10CFU with 100s of argon plasma treatment.The inactivation efficacy of 4.220 log10CFU was observed after 15s for 30％H2O2 plasma treatment time.The reduction of viable fungi was 4.442 log10CFU with the prolonged exposure time of 20s.The anticandidal efficacy of 4.306 log10CFU was achieved after 15s 50％H2O2 plasma treatment.The reduction of Candida albicans cells was increased further up to 4.618 log10CFU when 50％ H2O2 plasma treatment time extended to 20s.Conclusions:Argon,30％H2O2 and 50％H2O2 plasma are effective in inactivation of planktonic Candida albicans on the resin.The anticandidal effects of 30％H2O2 and 50％H2O2 plasma are superior to that of argon plasma.