Overnight storage of removable dentures in alkaline peroxide-based tablets affects biofilm mass and composition

Background Clinical guidelines for denture care are available, but evidence for optimal nocturnal storage is scarce. The aim of the study was to compare the role of the overnight storage state on plaque growth and composition on acrylic removable dentures. Methods In a parallel-group randomized controlled trial of 51 institutionalized participants, 3 denture overnight preservation methods were considered: (i) in water, (ii) dry or (iii) in water with added alkaline peroxide-based cleansing tablet. Biofilm samples were taken on day 7 (developing biofilm – d BF) and day 14 (maturing biofilm – m BF) from a mechanically uncleaned, standardized region, situated distally to the second lower premolars. Total and individual levels of selected perio-pathogenic and commensal species ( n = 20), and of Candida albicans were calculated by PCR. Differences between storage conditions (water/dry/tablet) and between the samples ( d BF/ m BF) were assessed by means of unpaired and paired t -tests respectively, with α = 5%. Results Overnight denture storage with cleansing tablet significantly decreased the total bacterial level of d BF and m BF up to 13.8%. Fn, Ec, Cs, Sc, Ao and Vp counts were particularly affected by tablet care. Significant lower amounts of Candida albicans for tablet storage compared to water preservation were recorded in d BF and m BF (−69.3 ± 3.8% and −75.9 ± 3.2% respectively). The mass and pathogenicity of d BF and m BF was equal, irrespective of the overnight storage intervention. Conclusions The use of cleansing tablets for acrylic removable denture overnight storage reduces denture biofilm mass and pathogenicity compared to dry and water preservation, and may contribute to the overall systemic health. Clinical significance Evidence-based clinical guidelines for overnight storage of removable acrylic dentures are lacking. The findings of this study indicate that alkaline peroxide-based cleansing tablets decrease bacterial and Candida levels in denture biofilms in case of poor oral hygiene. This provides evidence for a clinical guideline to minimize microbial load of dentures, thereby reducing associated systemic health risks.