Interkingdom interactions on the denture surface: Implications for oral hygiene

Area of Science:

• Oral microbiology
• Medical mycology
• Dental research

Background:

• Limited evidence exists for Candida species' role in oral diseases.
• Candida is an opportunistic yeast, often a commensal, implicated in denture-related issues.
• The precise role of Candida in denture biofilms and its interaction with bacteria requires further investigation.

Purpose of the Study:

• To investigate the role of Candida species in the oral microbiome of denture wearers.
• To explore how oral hygiene practices affect the denture's microbial and fungal composition.
• To understand interkingdom interactions between Candida and bacteria in the oral cavity.

Main Methods:

• In vitro studies using a 9-species interkingdom denture biofilm model to assess cleansing efficacy.
• Collection of oral hygiene data (OHIP, cleansing frequency, demographics) from 131 patients.
• Analysis of bacterial microbiome and quantitative PCR for fungal (ITS) and bacterial (16S) bioburden from dentures, mucosa, and teeth.

Main Results:

• Candida albicans in vitro was resistant to denture cleansing, unlike bacterial biofilms which repopulated but were treatable.
• Patient oral hygiene practices did not significantly alter Candida or bacterial composition or diversity.
• Candida load showed a suggestive gradient impacting bacterial composition, indicating interkingdom interactions, with significant correlations found between Candida and genera like Lactobacillus, Scardovia, and Fusobacterium.

Conclusions:

• The denture microbiome/mycobiome demonstrates resilience against common oral hygiene interventions.
• Candida species exhibit potential interactions with key oral bacterial genera, influencing community structure.
• These interactions may contribute to a shift from oral health towards disease states.