Graduate Research and Discovery Symposium (GRADS)


Dynamics of the Human Dental Microbiome

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The objective of this study was to characterize the oral microbiome (bacteria) and the oral mycobiome (fungi) as caries disease progresses, using site-specific sampling of teeth with different caries disease-states: caries free (PF), early-stage caries (caries in enamel tooth layer; PE), and advanced-stage caries (caries in dentin tooth layer; PD). Dental plaque samples were collected from 46 children (n=84). One plaque sample per caries disease state was collected from each patient (maximum of 3 samples per patient). To determine the changes in the oral microbiome/mycobiome amplicons of the V4 region of the bacterial 16S rRNA gene and the fungal ITS1 region were sequenced using Illumina’s MiSeq sequencing platform. Alpha diversity metrics (evenness, and species richness) showed no significant differences for either the fungal or bacterial plaque communities. Beta diversity was assessed using both Bray Curtis dissimilarity and UniFrac distance. Distinct bacterial communities were observed in PD samples when compared to PE and PF plaque communities (P<0.05). No significant differences in beta diversity were observed for the oral mycobiome samples. Interestingly, Streptococcus sobrinus and members from the genera Scardovia and Lactobacillus were observed only in diseased plaque samples, suggesting that these organisms may be important in caries disease progression. Distinct community composition differences were observed in bacterial PD communities when compared to PE and PF communities. The elucidation of the oral taxa in caries disease progression is crucial for a cognizant and holistic view of the human oral microbiome. Data from this study will aid with understanding the roles that fungi and bacteria play in dental cavity development, and will contribute insight into the etiology of dental caries disease which is crucial for development of treatment plans and preventative measures.

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