IL17A and Peri-Implantitis: Table 4 shows the frequency of the GG, GA, and AA genotypes, of IL-17A gene in patients with peri-implantitis, successful implants, and Healthy control groups, which were (50.0%), (17.9%), and (5.6%) respectively in peri-implantitis patients compared to (31.3%), (53.6%), and (41.7%) successful implants, and compared to (18.8%), (28.6%), (52.8%) healthy controls.