Investigation of the Impact of Peri-Implantitis Processes on Interleukin Profiles in Peri-Implant Crevicular Fluid

Objectives: This study aimed to verify the methodology for investigation of interleukin (IL) concentrations in peri-implant crevicular fluid (PICF) and to assess their correlation with clinical parameters, particularly bleeding on probing (BOP) and probing pocket depth (PPD). Material and Methods: PICF was collected from 60 peri-implantitis patients and 25 healthy volunteers to analyze IL levels in both groups. Sampling was conducted using sterile dental brushes, which were placed in the peri-implant crevice for up to 10 s. The brushes were then stored in Eppendorf tubes containing 1 mL of phosphate-buffered saline and centrifuged at 3000 rpm for 15 min. Samples were frozen at -80°C (193,15 K) for preservation. IL concentrations were measured using enzyme-linked immunosorbent assays (ELISA). Results: The study found significantly elevated levels of IL-1α, IL-6, IL-4, and IL-10 in PI patients compared to healthy controls. Correlation analysis revealed strong associations between BOP and IL-1α, IL-6, and IL-10, while PPD showed no significant relationship with IL levels. Among these, IL-10 had the greatest influence on BOP, highlighting its dual role in reducing excessive inflammation and sustaining chronic immune responses through immune tolerance. Conclusions: The present study demonstrated that IL-1α, IL-6, and IL-10 levels in PICF are closely associated with the severity of peri-implant inflammation. Among these cytokines, IL-10 showed the strongest relationship with BOP, indicating its important role in the modulation of local immune activity. IL-6 was also positively correlated with inflammatory severity, reflecting its involvement in sustaining the destructive processes within peri-implant tissues. Overall, the obtained data suggest that IL-6 and IL-10 may serve as useful indicators of ongoing inflammatory activity in peri-implantitis. However, their prognostic or diagnostic utility requires confirmation in longitudinal studies assessing temporal cytokine changes and treatment outcomes.