Clinical Severity, Pre- and Post-Explantation Cytokine Profile and SEM/EDX-Defined Corrosion-Related Findings in Advanced Peri-Implantitis: Preliminary Results from the PERI-EDU Prospective Exploratory Clinical Study

Background: Peri-implantitis is a chronic condition that reflects an interaction between local tissue destruction, systemic inflammation and corrosion-related implant alterations. This preliminary prospective exploratory clinical study aimed to characterize the systemic cytokine profile of patients with advanced peri-implantitis requiring explantation and to explore associations between clinical severity, cytokine behavior and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX)-defined corrosion-related findings. Methods: Thirteen patients with active advanced peri-implantitis were included. Probing depth and cone-beam computed tomography (CBCT)-based bone loss were assessed at four implant surfaces. Peripheral blood was collected before and 4 weeks after explantation. Serum interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-12p70 (IL-12p70), tumor necrosis factor alpha (TNF-α), high-sensitivity C-reactive protein (hsCRP), and fibrinogen were analyzed. Explanted implants underwent SEM/EDX assessment and were classified according to the presence or absence of SEM/EDX-defined corrosion-related findings. Results: IL-6 showed the strongest and most consistent associations with clinical and radiographic severity, whereas hsCRP and fibrinogen were not similarly related. Cytokines did not show a uniform post-explantation decrease after explantation. SEM/EDX-defined corrosion-related findings were not associated with higher baseline cytokines, but exploratory subgroup analysis suggested a divergent TNF-α trajectory. Conclusions: These findings suggest that IL-6 may reflect the clinical inflammatory burden of advanced peri-implantitis, while corrosion-related findings may be associated with post-explantation TNF-α behavior. Larger controlled studies are required.