(Polymorphisms, Genetic OR Gene Polymorphism OR Gene Polymorphisms OR Polymorphism, Gene OR Polymorphisms, Gene OR AND Interleukin 23 OR IL‐23 AND Interleukin 17 OR IL‐17 OR Interleukin 17A OR IL‐17A AND Periodontal Disease OR Periodontitis OR Chronic Periodontitis OR Aggressive Periodontitis OR Peri‐Implantitis). This evidence concerns the gene IL17A and chronic periodontitis.