Candida-associated denture stomatitis in nursing home residents is linked to poor oral hygiene. Objectives: the aim of this study was to test the efficacy of two methods of denture disinfection in nursing home residents over a two-year period. Methods: two methods of denture disinfection were assessed against a no-treatment group: sodium hypochlorite over-night soak and nightly microwave irradiation. Twenty nursing homes in the Central Sydney Area Health Service (CSAHS) were inspected and of 161 residents, 60 (37.3%) were diagnosed as having denture stomatitis and 101 (62.7%) had healthy mouths. Three independent observers were engaged to blind-analyze standardized photographs of subjects’ palates taken before and after one week’s treatment with either sodium hypochlorite or microwave irradiation or, in the case of controls, no treatment at all. The observers were asked to identify the before, after and no-treatment photographs. Results: the raters had difficulty in identifying the controls but were more successful with the treatments. The Pearson c 2 test therefore showed significant differences between the variables (p<0.007). However, all raters identified equally effective treatment by both methods regardless of the Candida strains (Pearson c 2 p>0.05). The Cronbach’s Alpha test (0.720) revealed good inter-rater reliability. Conclusions: the disappointing detection of controls was a concern and may indicate a Hawthorn effect and unreliability of photographs due to problematic standardization in the circumstances of aged subjects. However, the raters found that there was no difference between the disinfection of upper and lower dentures by sodium hypochlorite or microwave technique and this agreed with the microbiological analysis. This project was supported by the Australian Dental Research Foundation Inc. (grant number 40/2000) and a research grant from the Australian Prosthodontic Society (NSW Branch).