IL1A and chronic periodontitis: Our data demonstrate how the T allele predisposes the development of chronic periodontitis, such data becomes more significant when comparing it with a study on the same polymorphism, -889 C/T polymorphism in IL-1A, to a patient with peri-implantitis (P = 0.024), which showed an OR = 10.9 for individuals that presented previous periodontitis (37).