Herpesviruses: a unifying causative factor in periodontitis?

Human cytomegalovirus and Epstein-Barr virus type 1 are discussed in this r eview as they relate to destructive periodontal disease in humans. Genomes of the two herpesviruses occur frequently in severe adult periodontitis, lo calized and generalized juvenile periodontitis, Papillon-Lefevre syndrome p eriodontitis, Down's syndrome periodontitis, HIV-associated periodontitis a nd acute necrotizing ulcerative gingivitis, Herpesvirus infections generall y involve a mild or asymptomatic primary phase followed by an asymptomatic latent phase interrupted sporadically by periods of activation, where viral replication and possibly clinical disease become manifest. Herpesvirus rea ctivation is triggered by a number of immunosuppressing factors, some of wh ich have also been shown to be risk indicators of periodontal disease. Avai lable evidence argues for the involvement of active cytomegalovirus infecti on in the initiation and progression of localized juvenile periodontitis an d possibly other types of periodontal disease. In periodontal disease, herp esviruses may cause release of tissue-destructive cytokines, overgrowth of pathogenic periodontal bacteria, and initiation of cytotoxic or immunopatho genic events. Understanding the significance of herpesviruses in the causat ion and pathogenesis of destructive periodontal diseases may have important implications in future prevention and treatment of the diseases.