ASSESSMENT OF THE IMPACT OF CLEANING METHODS AND OVERNIGHT DENTURE STORAGE ON BIOFILM FORMATION ON REMOVABLE ACRYLIC DENTURES.

Aim of the study

The presence of a biofilm - i.e. structured microbial communities that are attached to a surface and encased in an exopolymer matrix - on acrylic removable dentures has been associated with serious systemic conditions, especially in the dependent elderly [1]. Oral bacteria have been implicated in bacterial endocarditis [2], aspiration pneumonia [3, 4], chronic obstructive pulmonary disease [5, 6], amongst other diseases [1, 7]. Ample evidence is provided regarding the relationship between proper oral hygiene and overall systemic health.

Plaque on dentures is a complex aggregate containing more than 108 organisms per milligram, and involving more than 600 prokaryote species [8]. The different species collaborate to form a symbiotic biofilm. The biofilms in dentate patients have been studied extensively, but there have been few studies on the biofilm microbiota of complete acrylic dentures [10-18]. It appears that distinct biofilms, with associated pathogenic risks, are present in 'healthy' versus denture stomatitis affected participants [15, 16, 18]. Not only poor denture cleaning but also inappropriate habits, such as wearing dentures overnight have proved to be associated with the prevalence of Candida-associated stomatitis [19, 20]. Therefore, the overnight removal of the acrylic removable dentures is advised in clinical settings. Although evidence-based guidelines for denture care and maintenance are available [21], guidelines for nocturnal storage conditions of dentures are missing. The investigators therefore performed a study (submitted for publication) to evaluate the effect of different overnight storage protocols on denture biofilm formation and maturation. The results of this study showed that the use of cleansing tablets (Corega Tabs Anti-bacteria®, GlaxoSmithKline Consumer Healthcare SA, Genval, Belgium) for acrylic removable denture overnight storage reduces denture biofilm mass and pathogenicity compared to dry and water preservation.

As no mechanical denture cleaning was performed in the aforementioned study, the aim of the proposed study is to evaluate the combined effect of mechanical cleaning and overnight storage condition on the microbial composition and Candida albicans colonization of denture biofilm formation. This information is required to develop a clinical guideline on acrylic denture cleaning and overnight storage aiming to reduce the risk posed by pathogenic microorganisms, particularly in bedridden and immunocompromised patients.

Research questions