Oral Microbiota in Healthy Versus Diseased Periodontal and Peri-implant Niches

Objectives: The microbiota present within diseased periodontal or peri-implant niches is typically highly distinct from that present within corresponding healthy sites. However, differences between the microbiota of individual tooth/implant sites of differing health status, within the same oral cavity, remain largely unexplored. To characterize the subgingival/submucosal microbiota of healthy and diseased periodontal/peri-implant sites in individuals presenting with both periodontitis and peri-implantitis.
Methods: Eighteen implant-rehabilitated, partially-dentate Chinese subjects (n=18) who had developed periodontal and peri-implant infection were included. Subgingival/submucosal plaque samples were collected from four clinically-distinct sites in each subject: i) healthy peri-implant tissues (HI); ii) peri-implantitis (DI); iii) healthy gingiva (HT), iv) periodontitis (DT). The microbiota present within each clinical site (n=72) was analyzed by 16S rRNA amplicon sequencing (V3-V4) using the Illumina MiSeq platform (PE300). Data was analyzed using QIIME and other bioinformatic and statistical approaches.
Results: A total of 4,425,705 quality-filtered 16S reads were obtained, which were assigned to 5,726 operational taxonomic units (OTUs; 97% cut-off). Bacterial taxa from 26 phyla comprising 396 genera were identified. Statistical as well as phylogeny-based analyses (including Chao1, Observed OTU index, PD whole tree, Unifrac) indicated that there were no major differences in overall bacterial diversity levels, nor community structure, present within the HI, HT, DI and DT sites. However, 37/396 and 51/396 genera were unique to tooth sites and implant sites, respectively. Notably, Campylobacter taxa were more abundant in DI sites compared with HI sites (p=0.04). Halomonas were more abundant in DI sites than in DT sites (p=0.04).
Conclusions: Within this cohort of subjects presenting with both periodontitis and peri-implantitis infections, the respective microbial communities present within healthy and diseased tooth/implant sites share very high levels of similarity. Further research is warranted to identify the precise etiological/pathophysiological factors that underlie the differences in peri-implant and periodontal disease status.