Cytokine expression in peri-implant crevicular fluid in relation to bacterial presence

The aim was to assess clinical inflammatory parameters, cytokine levels and bacterial counts in samples from implant crevicular fluid in cases with untreated peri-implantitis.

Several bacterial species known to up-regulate pro-inflammatory cytokines have been associated with peri-implantitis. The Luminex magnet bead technology was used to study cytokines in crevicular fluid. The checkerboard DNA-DNA hybridization method was used to study bacterial counts in samples from 41 implants (41 individuals).

Profuse bleeding and suppuration was found in 25/41 (61.0%) of the implants. The reliability of duplicate cytokine processing was high. In the presence of profuse bleeding, higher pg/ml levels of IL-1β (p = 0.02), IL-8 (p = 0.04), TNF-α (p = 0.03) and VEGF (p = 0.004) were found. Higher concentrations of IL-1β were found in the presence of suppuration, and if Escherichia coli (p = 0.001) or Staphylococcus epidermidis (p = 0.05) could be detected.

Profuse bleeding and/or suppuration in untreated peri-implantitis can be associated with higher concentrations of IL-1β, IL-8, TNF-α and VEGF in peri-implant crevicular fluid. A higher concentration of IL-1β in peri-implant crevicular fluid was found in samples that were positive for E. coli or S. epidermidis.