Effects of denture disinfection methods on survival of Candida albicans

Objectives: The purpose of this study is to investigate the efficacy of two methods of denture disinfection against Candida albicans : (1) microwave(M-M209E, LG, Seoul, South Korea) irradiation and (2) alkaline peroxide denture cleanser (PolidentⓇ, Block Drug Co, Inc., NJ USA).

Methods: Upper acrylic resin dentures were fabricated and incubated with C. albicans. Five dentures were microwaved and five controls were not microwaved. A range of exposure times of 1, 2, 3, 4, 5 and 6 minutes was selected. After microwaving, the denture washing solutions were plated out onto agar, and the colony forming units per milliliter were calculated. The same procedure was followed on alkaline peroxide denture cleanser. A range of soaking times was 5-min, 30-min, 1-hour, 3-hour, 6-hour, 9-hour. To validate the disinfection effect, fluorescence microscopy (axioskop, Zeiss, Jena, Germany) was used. The change of surface roughness and dimensional stability were compared to evaluate the influence of two methods on denture base.

Results: (1) The minute irradiation of microwave and 5 minute immersion in alkaline peroxide solution resulted in a significant decrease in the survival rate of C. albicans (p < 0.05). (2)The 4-minute irradiation of microwave and 6 hour treatment in alkaline peroxide solution resulted in sterilization of the complete denture contaminated with C. albicans. (3) In fluorescence micrography, no living microorganisms were found on the surface of the specimens treated with microwave or alkaline peroxide solution for 5 minutes. (4) The denture treated with alkaline peroxide solution for 6 hours a day for 3 weeks showed a significance increase in surface roughness (p< 0.05). (5) There was no clinically significant difference in dimensional changes between the control and the microwaved denture for 5 minutes a day for 3 weeks.

Conclusion: Microwave irradiation is proposed as a simple, effective and inexpensive method for denture disinfection.