TNF and Peri-Implantitis: Therefore, the purpose of this case-control study was to compare the levels of cytokines (IL-1β, IL-2, IL-4, IL-6, MCP-1, MIP-1α, MIP-1β, and TNF-α) and the presence of human herpesviruses (HSV-1, HSV-2, EBV, CMV, VZV, HHV6, HHV7, and HHV8) in saliva samples taken from subjects with and without peri-implantitis.