Effect of microwave disinfection in the treatment of denture stomatitis

Objective: The aim of this in-vivo study was to identify the most effective frequency of microwave disinfection to reduce Candida colonization on complete dentures from patients with denture stomatitis. Methods: Twenty nine patients with denture stomatitis were instructed to scrub their dentures with coconut soap and water four times a day and soak it in water overnight. Patients were randomly divided into three groups. Control group (CG): patients received topical antifungal medication (Nystatin oral suspension 100, 000 UI/mL) 4x/daily for 14-days. Test group 1 (TG1): patients had their maxillary denture immersed in water and microwaved (650W/3min) 1x/week for 14-days. Test group 2 (TG2): patients had their maxillary denture immersed in water and microwaved (650W/3min) 3x/week for 14-days. Mycological samples were taken from the tissue side of the upper dentures for each patient before treatment (day-0), after starting treatment (15-days) and follow-up (30, 60, 90-days). Samples were cultured in CHROMagar¢s plates and incubated (30°C, 5-days). Candida spp. colonies were quantified (cfu/mL) and submitted to identification by micro-cultivation in lamina, hypertonic Sabouraud broth and bioMérieux 32C. Data were analyzed using Kruskall-Wallis test (a=0.05). Results: Patients in CG, TG1 and TG2 presented a decrease in colonization of Candida species on complete dentures after treatment, when compared with pretreatment results. The mean percentage reductions of Candida colonization in CG, TG1 and TG2 were 64.61, 67.77, 69.75%, respectively. There were no significant differences in the reduction of Candida counts in the follow-up (30, 60, 90-days) treatment of denture stomatitis when the three groups were compared. There were no significant changes in the species of Candida that colonized complete dentures before treatment, after starting treatment and follow-up. Conclusion: Microwaving dentures appeared to be useful for decreasing the Candida spp. colonies present in complete dentures from patients with denture stomatitis.

Grant: FAPESP 05/03211-6 and 05/04695-7.