Abstract
            Background. This study evaluated the gingival crevicular fluid (GCF) and Peri- implant crevicular  fluid (PICF) concentrations of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis  factor-alpha (TNF-α) and active metalloproteinase-8 (a-MMP-8) in sites with healthy conditions  vs. sites affected by periodontitis (PER) and peri-implantitis (PIM).  
  Methods. Periodontally healthy (PH) sites with PER, sites with peri-implant health (PIH), and  sites with PIM were investigated intra-individually, according to the inclusion criteria of each  group. Probing pocket depth (PPD), plaque index, gingival index, and the presence or absence of  bleeding on probing (BoP) were evaluated. In GCF and PICF samples, IL-1β, IL-6, and TNF-α were  quantified by ELISA Duoset® kit in combination with Ultramark® micro-ELISA digital reader;  a-MMP8 concentration was analyzed by a chairside test (Perio/ImplantSafe®) in combination  with a digital reader (ORALyzer®).  
  Results. The concentrations of IL-6 and IL-1β, TNF-α, and a-MMP-8 were significantly higher in  the PIM and PER sites compared to healthy sites (P<0.05). Significantly higher concentrations of  IL-1β and a-MMP-8 were found in PIM vs. PER sites (P<0.05), while the concentrations of IL-6  and TNF-α did not differ between the PIM and PER groups (P>0.05).  
  Conclusion. aMMP-8, IL-6, IL-1β, and TNF-α presented higher GCF/PICF concentrations in  diseased periodontal and peri-implant sites. However, only the concentrations of IL-1β and  a-MMP-8 were significantly higher in PIM than in PER sites.