IL17A and periodontitis: In order to investigate whether IL17A and the IL17F polymorphisms are associated with chronic periodontal disease and understand its immunopathogenesis, this study aimed at evaluating the IL17A G197A (rs2275913) and IL17F T7488C (His161Arg, rs763780) polymorphisms in patients with chronic periodontitis and in a healthy group who had undergone dental care in the North/Northwest of the state of Paraná, Southern Brazil.