Materials and methods: In vitro denture cleansing studies were performed on a complex 9-species interkingdom denture biofilm model, with quantitative assessment of retained bacterial and fungal viable bioburdens. Patient hygiene measures were also collected from 131 patients, including OHIP, frequency of denture cleansing, oral hygiene measure and patient demographics. The bacterial microbiome was analysed from each patient, alongside quantitative PCR assessment of ITS (fungal) and 16S (bacterial) bioburden from denture, mucosa and intact dentition.
Results: It was shown that following in vitro denture cleansing C. albicans were unresponsive to treatment, whereas bacterial biofilms could repopulate 100-fold, but were susceptible to subsequent treatment. Within the patient cohort, oral hygiene did not impact candidal or bacterial composition, nor diversity. The levels of Candida did not significantly influence the bacterial microbiome, though an observed gradient was suggestive of a microbial composition change in response to Candida load, indicating interkingdom interaction rather than an oral hygiene effect. Indeed, correlation analysis was able to show significant correlations between Candida species and key genera (Lactobacillus, Scardovia, Fusobacterium).
Conclusions: Overall, this study has shown that the denture microbiome/mycobiome is relatively resilient to oral hygiene challenges, but that Candida species have potential interactions with key oral genera. These interactions may have a bearing on shaping community structure and a shift from health to disease when the opportunity arises.
- oral hygiene