Thirty-four institutionalized subjects (mean age, 81 years) with a positive test for C. albicans pseudohyphae were randomly assigned to test (microwave) and control (soak) groups. All subjects received the same course of topical antifungal medication (Nystatin 300,000 IU lozenges 3x daily for 14 days). Subjects in the microwave treatment group had their maxillary denture scrubbed and then microwaved for one minute at 850 Watts. This procedure was repeated three times. For subjects receiving the standard denture soak treatment, the nursing staff was instructed to disinfect the maxillary dentures in 0.2% chlorhexidine digluconate solution overnight for 14 days, changing the solution every two days. Infestation of the tissue surface of the maxillary denture with C. albicans progressively took place over the three-month period following treatment such that 8 (53%) of the microwaved dentures and 16 (84%) of the soaked dentures demonstrated pseudohyphae as determined by Gram stain. Infection of the soft tissues with the hyphal form of C. albicans also increased with time. After three months, one (8%) patient in the microwave group and 12 (63%) patients in the denture soak group demonstrated pseudohyphae on the cytological smears. Re-infestation of the denture surface and infection of the adjacent soft tissue were delayed dramatically in patients whose dentures were microwaved compared with those whose dentures were disinfected by being soaked in a chlorhexidine solution. However, microwave treatment is not recommended for all dentures and should be used with caution.

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