IL6 and Peri-Implantitis: Similarly, Khichy et al. [39] reported in a study involving 40 patients (20 with peri-implantitis; 20 controls) higher CRP (0.795 versus 0.294 mg/dL) and IL-6 (12.178 versus 6.458 pg/mL) levels in peri-implantitis.