Efficacy of removing Candida albicans from orthodontic acrylic bases: an in vitro study

BACKGROUND: This study evaluated the efficacy of four methods in removing Candida albicans from the acrylic base material used to fabricate removable orthodontic appliances. METHODS: Heat-processed bars of orthodontic acrylic were incubated in a suspension of C. albicans for 2 h at 37 °C. Samples were allocated into five groups (five bars per group) according to the cleaning method: (1) manual brushing using a toothbrush; (2) soaking in a commercial denture cleaning solution; (3) soaking in a commercial mouthwash solution; (4) using an ultrasonic cleaner; and (5) soaking in distilled water as a negative control. Yeast remaining attached to the bars after cleaning were removed by vortexing in growth medium and plated on Sabouraud dextrose agar. The reduction in yeast colony count after cleaning was calculated and expressed as the number of colony forming units per acrylic bar (CFU/bar). The experiment was carried out three times. RESULTS: All four cleaning methods resulted in a significant decrease in viable yeast cells associated with the acrylic bars compared to the control group. The mean percentage reduction in viable yeast cells affected by the cleaning methods was: brushing 89.9%; chlorhexidine 95.8%; ultrasonic cleaning 99.9%; and denture tablet 100%. CONCLUSIONS: All four methods evaluated in this study were effective, to some extent, in removing C. albicans from orthodontic acrylic samples. The most effective, and readily available, cleaning method was the use of commercial denture sterilizing tablets.