The Oral Microbiome of Denture Wearers Is Influenced by Levels of Natural Dentition

Abstract

ObjectivesThe composition of dental plaque has been well defined, whereas currently there is limited understanding of the composition of denture plaque and how it directly influences denture related stomatitis (DS). The aims of this study were to compare the microbiomes of denture wearers, and to understand the implications of these towards inter-kingdom and host-pathogen interactions within the oral cavity.MethodsSwab samples were obtained from 123 participants wearing either a complete or partial denture; the bacterial composition of each sample was determined using bar-coded illumina MiSeq sequencing of the bacterial hypervariable V4 region of 16S rDNA. Sequencing data processing was undertaken using QIIME, clustered in Operational Taxonomic Units (OTUs) and assigned to taxonomy. The dentures were sonicated to remove the microbial flora residing on the prosthesis, sonicate was then cultured using diagnostic colorex Candida media. Samples of unstimulated saliva were obtained and antimicrobial peptides (AMP) levels were measured by ELISA.ResultsWe have shown that dental and denture plaques are significantly distinct both in composition and diversity and that the oral microbiome composition of a denture wearer is variable and is influenced by the location within the mouth. Dentures and mucosa were predominantly made up of Bacilli and Actinobacteria. Moreover, the presence of natural teeth has a significant impact on the overall microbial composition, when compared to the fully edentulous. Furthermore, increasing levels of Candida spp. positively correlate with Lactobacillus spp. AMPs were quantified, though showed no specific correlations.ConclusionsThis is the first study to provide a detailed understanding of the oral microbiome of denture wearers and has provided evidence that DS development is more complex than simply a candidal infection. Both fungal and bacterial kingdoms clearly play a role in defining the progression of DS, though we were unable to show a defined role for AMPs.

The Denture-Associated Oral Microbiome in Health and Stomatitis

“…Similar to our results, a recent sequencing study (12) and older culture-based approaches (11, 16, 24) found no difference in the apparent microbial composition between healthy and stomatitis patients and noted only that the amount of plaque buildup is significantly greater in stomatitis patients. In contrast, a clone library-based culture-independent study (10) reported that the microbiota of biofilms colonizing dentures in health and disease are distinct.…”

“…A detailed clone library analysis (10) provided a first glimpse into the diversity of bacterial phylotypes associated with dentures in health and disease, while a recent predominantly class and phylum level study (12) introduced modern sequencing approaches to the field. The data presented here comprise the first comprehensive genus and species level analysis of the bacteria residing in biofilms on the dentures and remaining teeth of healthy patients and those with stomatitis.…”

“…Very few studies have assessed bacterial denture colonization by using culture-independent clone library and checkerboard approaches (10, 14, 15, 17). To date, only one recent study has reported a next-generation sequencing analysis, which provided an initial predominantly class level analysis of the microbiota colonizing dentures, the respective mucosal surfaces, and selected remaining teeth (12). While this is an important step toward understanding the bacterial component of health and disease in denture wearers, a recent comprehensive evaluation of different oral sites at the oligotype level has highlighted the importance of resolving communities at more detailed taxonomic levels to better understand the ecological and functional diversity of the microbiota relevant to health and disease (25).…”

Candida albicans biofilm heterogeneity does not influence denture stomatitis but strongly influences denture cleansing capacity

“…Nevertheless, a positive correlation between the absolute candidal numbers and disease was observed, suggesting that the physical interaction between large numbers of yeasts and hyphae on the denture surface was more important than the phenotype per se. This is likely influenced by the diverse microbiota in this environment, which we have recently described (22). Indeed, there is increasing evidence that Candida and bacteria form polymicrobial biofilms, and that some bacterial species common to the oral cavity can enhance the pathogenicity of C. albicans (35)(36)(37)(38), and that the presence of specific oral bacteria is enough to transform a C. albicans LBF into a HBF (39).…”

“…Samples for this study were obtained from 129 denture wearers attending the Glasgow Dental Hospital and School for routine treatment, as previously described by our group (22). Written informed consent was obtained from all participants.…”