The Etiology Of Peri-implantitis: Microbiome Analysis Within And Outside Dental Implants

Objectives: The incidence of peri-implantitis has been steadily increasing and the importance of dental biofilms in the etiology of peri-implantitis has been extensively studied. However, little is known about the bacteria harbored within the internal hollow compartment of dental implants. This hollow compartment serves as a reservoir that may harbor pathogenic bacteria that may contribute to the etiology of peri-implantitis. The purpose of this study was to compare the microbiome within implants of peri-implantitis subjects to that of healthy controls using culture independent metagenomic methods.
Methods: A total of 20 endosseous implants from affected (peri-implantitis) and healthy controls (n=10/group) were included in this cross-sectional study. Samples for microbiological analysis were obtained from peri-implant pocket and internal surfaces of dental implants using sterile paper-points. Samples from buccal/labial mucosa, gingival mucosa, tongue, and contralateral healthy teeth were collected as controls. DNA was extracted and the 16S rRNA gene was amplified using universal primers targeting the V3-V4 regions. Amplicons were sequenced using illumine MiSeq platform. Alpha and beta diversity were assessed. The phylotypes were identified by comparison with open source rRNA database.
Results: The microbiome composition of the internal implant surface demonstrated significantly lower diversity than the corresponding peri-implant pocket in both healthy and diseased implants. An increase in microbial diversity was observed in the internal implant surface of peri-implantitis compared with the internal surfaces of healthy implants. Several species, including periopathogenic bacteria and unknown organisms, were unique to the inner surface of implant with peri-implantitis.
Conclusions: The internal implant surface of peri-implantitis was contaminated by periopathogenic bacteria different than theinternal surface of healthy implants. The microbial colonization within that space might contribute to the etiology of peri implant disease.