Factors which increase the risk of severe adult periodontitis (AP) may also contribute to the success of dental implants. To determine which cytokines may be relevant, levels of interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-1 receptor antagonist (IL-1ra), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) mRNA were quantitated in gingival tissue from periodontitis patients and healthy controls. Periodontitis significantly increased levels of IL-1alpha, IL-1beta, IL-6 and IFN-gamma mRNA relative to healthy tissues. IL-1 was selected for further study, as it has inflammatory and bone resorbing properties. We examined IL-1A(-889) and IL-1B(+3953) alleles in Caucasian patients with AP and early-onset periodontitis (EOP), patients with dental implants and healthy individuals. The IL-1B(+3953) polymorphism was associated with AP. This was evident from an increased homozygosity for allele 2 in patients with AP and a decreased heterozygosity in advanced AP patients. IL-1A(-889) and a composite genotype [IL-1A(-889)2 plus IL-1B(+3953)2] showed no association with the incidence of periodontitis, disease onset or disease severity. IL-1A(-889), IL-1B(+3953) and the composite genotype also showed no association with failure of dental implants.