Clinical, microbiological, and immunological aspects of healthy versus peri-implantitis tissue in full arch reconstruction patients: a prospective cross-sectional study

Background: Due to the world-wide increase in treatments involving implant placement, the incidence of peri-implant disease is increasing. Late implant failure is the result of the inability to maintain osseointegration, whose most important cause is peri-implantitis. The aim of this study was to analyze the clinical, microbiological, and immunological aspects in the peri-implant sulcus fluid (PISF) of patients with healthy dental implants and patients with peri-implantitis. Methods: PISF samples were obtained from 24 peri-implantitis sites and 54 healthy peri-implant sites in this prospective cross-sectional study. The clinical parameters recorded were: modified gingival index (mGI), modified plaque index (mPI) and probing pocket depth (PPD). The periodontopathogenic bacteria Tannerella forsythia, Treponema denticola and Porphyromonas gingivalis were evaluated, together with the total bacterial load (TBL). PISF samples were analyzed for the quantification of Interleukin (IL)-8, IL-1 beta, IL-6, IL-10 and Tumor Necrosis Factor (TNF)-alpha using flow cytometry (FACS). Results: The mGI and PPD scores in the peri-implantitis group were significantly higher than the healthy group (p < 0.001). A total of 61.5% of the patients with peri-implantitis had both arches rehabilitated, compared with 22.7% of patients with healthy peri-implant tissues; there was no implant with peri-implantitis in cases that received mandibular treatment exclusively (p < 0.05). Concentrations of Porphyromonas gingivalis (p < 0.01), association with bacteria Porphyromonas gingivalis and Treponema denticola (p < 0.05), as well as the TBL (p < 0.05) are significantly higher in the peri-implantitis group. IL-1 beta (p < 0.01), IL-6 (p < 0.01), IL-10 (p < 0.05) and TNF-alpha (p < 0.01) are significantly higher at the sites with peri-implantitis compared to healthy peri-implant tissue, while IL-8 did not increase significantly. Conclusion: The results of the present study involving a limited patient sample suggest that the peri-implant microbiota and which dental arch was rehabilitated involved could contribute to bone loss in peri-implantitis. A significant relationship is observed between the concentration of cytokines (interleukins 1 beta, 6 and 10 and TNF-alpha) and the inflammatory response in peri-implantitis tissue.