Investigation of Macrophage Polarization in Peri-implant Health and Peri-implantitis

Peri-implantitis is a chronic inflammatory disease characterized by plaque-associated inflammation of the peri-implant mucosa and progressive loss of supporting bone around dental implants, which may ultimately lead to implant failure if left untreated. It has been demonstrated that cellular and molecular responses of the host immune defense system play a critical role in the pathogenesis of peri-implantitis. Macrophages are key cells in the host immune response and are generally classified into two phenotypes: pro-inflammatory (M1) and anti-inflammatory (M2). While M1 macrophages are actively involved in the early defense response, a shift toward the M2 phenotype is required for the resolution of inflammation and tissue repair. Smoking has been shown to adversely affect macrophage polarization and function, thereby exacerbating inflammatory responses. Therefore, in the present study, levels of soluable CD163 (sCD163), B cell activating factor (BAFF), tumor necrosis factor-like weak inducer of apoptosis (TWEAK), a proliferation-inducing ligand (APRIL), interferon-gamma (IFN-γ), interleukin-10 (IL-10), interleukin-34 (IL-34), interleukin-35 (IL-35), and arginase activity (ornithine levels) will be evaluated in peri-implant health and peri-implantitis patients with varying disease severity and different smoking statuses. In addition, a comprehensive proteomic analysis will be performed to investigate the relationships among peri-implantitis severity, smoking, and macrophage polarization-related molecules. Baseline periodontal and peri-implant parameters will be recorded for all participants. In the peri-implant health group, tissue samples will be collected during exposure surgery performed for submerged implants, after which participants will be enrolled in supportive peri-implant care. Participants diagnosed with peri-implantitis will receive non-surgical therapy, during which tissue samples will be collected. Periodontal and peri-implant parameters will be reassessed for all participants at baseline, and at 6 and 12 weeks. Healthy peri-implant samples will be collected from submerged implants during exposure surgery. Peri-implantitis samples (probable pocket depth ≥ 6 mm with bleeding on probing) will be obtained during non-surgical therapy using a single stroke along the pocket wall.