EFFECTIVENESS OF 2 METHODS OF DENTURE STERILIZATION

Species of Candida and in particular Candida albicans may be involved in the aetiology of denture stomatitis. Studies have shown that Candid a and other oral micro-organisms including Streptococcus gordonii are associated with denture plaque; hence denture hygiene is an important factor in the prevention and treatment of the disease. The aim of this investigation was to test in vitro the efficacy of two methods of den ture sterilization: (1) microwave irradiation and (2) sodium hypochlor ite soak. Twenty upper acrylic dentures were prepared for microbiologi cal assay; 10 were inoculated with C. albicans H1 and 10 with S. gordo nii LGR2. Within each group, five dentures were tested in a domestic m icrowave oven for optimal exposure time and temperature to ensure ster ilization; the five control dentures were not microwaved. Microbiologi cal analyses showed that the inoculated dentures became sterile after six min of irradiation at medium setting (2450 MHz, 350 W). Damage to the microorganisms after microwave irradiation was clearly visible by scanning electron microscopy (SEM). Following the same protocol as abo ve, experimental dentures were soaked for 8 h in either 0.02%, or 0.01 25% sodium hypochlorite solution and control dentures soaked in distil led water. Microbiological analyses showed that the experimental dentu res inoculated with C. albicans H1 became sterile. By contrast, those inoculated with S. gordonii LGR2 did not become sterile, and the SEM p rocedures confirmed these findings. The results of this study indicate that microwaving may be a more effective method of denture sterilizat ion than denture soaking in sodium hypochlorite. However, compared wit h microwaving, hypochlorite reduces the levels of residual non-viable micro-organisms attached to the denture surface.