Use of microwave energy to disinfect a long-term soft lining material contaminated with Candida albicans or Staphylococcus aureus

Statement of problem. Soft lining materials have been found to be more susceptible to microbial adhesion than acrylic resin base materials. Denture hygiene is essential to maintain the serviceability of the denture, and micron ave energy has been suggested for denture disinfection. Purpose. The purpose of this study was to determine the effectiveness of microwave energy in the disinfection of a long-term soft lining material. Material and methods. A long-term soft lining material was contaminated with known microorganisms and the reduction of organism counts after test disinfection regimes calculated. The disinfection regimes were microwaving for 5 minutes, leaving dry overnight, and soaking overnight in a dilute sodium hypochlorite solution. The test microorganisms were Candida albicans or Staphylococcus aureus. Results. For both organisms, soaking in sodium hypochlorite reduced the number of viable adherent microorganisms recovered significantly more than exposure to microwave energy, which led to greater reduction than leaving the lining material dry overnight (p < 0.001, Wilcoxon nonparametric signed rank test). Conclusion. With reference to the tested microorganisms, disinfection of Molloplast-b soft lining material in dilute sodium hypochlorite solution proved to be more effective than exposure to microwave energy, which in turn was more effective than leaving the lining dry overnight.