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

AIM: 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.

MATERIAL AND METHODS: 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).

RESULTS: Profuse bleeding and suppuration was found in 25/41 (61.0%) and 17/41 (41.5%) 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 = 0.016), IL-8 (p = 0.003), TNF-α (p = 0.024), 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.

CONCLUSION: 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.