A higher concentration of IL-1b, interleukin-8 (IL-8), TNF-α, tissue inhibitor of metalloproteinase-2 (TIMP-2), vascular endothelial growth factor (VEGF), and osteoprotegerin (OPG) have been reported in the peri-implantitis crevicular fluid, in comparison to healthy implants [14,133,134]. The gene discussed is CXCL8; the disease is Peri-Implantitis.