Dentures Biofilm and Artificial Biofilm Substitute

The bacterial biofilm on the intraoral surfaces is a three-dimensionally structured, firmly adhering layer of microorganisms surrounded by a matrix of extracellular polymeric substances (EPS). This matrix can take up to 90% of the biofilm mass. Biofilm on oral surfaces can lead to diseases such as caries, periodontitis or denture stomatitis. Furthermore, an association between denture biofilm, which serves as a reservoir for various bacteria, and general diseases is described. Adequate denture hygiene is therefore essential for maintaining the health of denture wearers. Nevertheless, adequate oral and denture hygiene is not sufficiently available for many, especially institutionalized elderly. The reasons are mostly insufficient preventive measures to train denture wearers, nursing staff and family members, as well as a lack of training materials such as dentures with artificial biofilm equivalents, which have the same cleaning properties as real dentures biofilm.

The absence of such appropriate substitutes for denture biofilm requires innovations in this field. Further, clinical data for validation of innovative artificial biofilm substitutes are missing.

The aim of this pilot study is to carry out preliminary tests for the development of a polysaccharide-based artificial biofilm substitute to simulate the real denture biofilm and to verify the feasibility of the study protocol, design and methods i.e. recording the obligatory manual and mechanical brushing cycles or for adapting the mechanical properties and adhesive strength to the clinically recorded data.

This pilot study includes 2 in vivo and 3 in vitro parts. The in vivo examinations contain 8 visits for participants. For biofilm formation participants omit cleaning dentures for 12 and 36 hours. Biofilm formation occurs between the visits and removal within the visits. Digital planimetry will be performed to measure the biofilm formation and removal. Within 3 in vitro tests, the mechanical properties of the artificial biofilm substitutes will be adjusted and the reliability tested. The artificial biofilm contains chitosan and methylcellulose. The mechanical brushing cycles needed to remove artificial biofilm substitutes, will be measured by a tooth-brushing simulator under standardized conditions. Digital planimetry of artificial biofilm after brushing will be performed.

The collected data will be used for further conceptualization of the main study.

Inclusion criteria

• Individuals 18 years of age or older
• Individuals wearing sufficient acrylic resin (PMMA) complete upper or complete upper and lower denture
• healthy oral mucosa
• written informed consent

Exclusion criteria

• Individuals who have severe systemic and/or infectious diseases
• Female individuals who are pregnant or breastfeeding
• allergies or hypersensitivity to the used products and/or materials
• smokers
• Individuals with a history of chronic drug abuse or another illness which does not allow the participant to assess the nature and/or possible consequences of the study
• inability to comply with study protocol requirements
• Individuals who have participated in another clinical study less than 4 weeks prior to the baseline examination