Highly Spatial Mapping of Oral Microbial Communities in Peri-implant Health and Disease

Abstract

Background: Peri-implant mucositis and peri-implantitis are pathological conditions occurring in tissues around dental implants. Both diseases are characterized by inflammation in the peri-implant connective tissue, but peri-implantitis additionally involves progressive loss of supporting bone. Previous studies have utilized 16sRNA sequencing which have revealed the severity of human peri-implant disease lesions correlated with the level of submucosal microbial dysbiosis. However, the spatial arrangement of these microbial communities remains largely unknown. Hypothesis & Specific Aims: The aim of this study is to elucidate the composition and spatial organization of oral microbial communities in periimplant health (PIH) and peri-implant disease (PID) at the single-cell resolution. Our central hypothesis is that peri-implant microbiomes in PIH and PID exhibit different compositions and spatial organizations indicative of their ecological interactions. Consequently, our specific aims are: 1) 1) To identify structural differences in microscale spatial arrangement of peri-implant microbial communities in PIH and PID. 2) To identify characteristic motifs in the microscale spatial organization of taxa in PIH and PID 3) To explore the relationship between the severity of PID and microbial spatial organization. We hypothesize that PIH and PID have different spatial arrangement and distinct characteristic motifs. In addition, microbial spatial organization may differ depending on diseases severity. Material & Methods: Subgingival microbial plaque samples from health peri-implant sulcus (n = 26), peri-implant mucositis sulcus (n = 15), untreated peri-implantitis sulcus (n = 19) were obtained from 60 non-smoking, systemically healthy patients during standard of care clinical procedures (IRB21-0662). All patients completed baseline clinical measurements (probing depth, recession, bleeding on probing, plaque index), and full-mouth radiographs (periapical and/or bitewing) to assess peri-implant disease severity and establish a diagnosis. For measuring microbial composition, we used third generation long read sequencing of the full 16sRNA gene. For surveying microbial spatial organization, we utilized highphylogenetic-resolution microbiome mapping by fluorescence in situ hybridization (HiPR-FISH), which is a novel and versatile technology that uses binary encoding, spectral imaging, and machine learning decoding to create micrometer-scale maps of the locations and identities of microbial species in complex communities. Key Innovation: High-phylogenetic-resolution microbiome mapping by fluorescence in situ hybridization (HiPR-FISH) provides an advanced and contemporary framework for analyzing the microscale spatial ecology of environmental microbial communities at the single-cell resolution. Thus, the novel technology can be used to make significant progress in our understanding of peri-implant microbiome ecology