Immunological Insights into Periodontal Disease Pathogenesis: A Review

Periodontal diseases are chronic inflammatory diseases of multifactorial etiology, common in all human populations, which may result in the gradual destruction of the supporting tissue of the teeth and ultimately tooth loss. Accumulation of plaque has been accepted as the primary initiator of periodontal disease, but it is not solely responsible for the destruction that may follow. The destruction seen in periodontal disease is a consequence of the interaction between the host and microorganisms present in plaque which results in the activation of the host's inflammatory and immune responses, leading to loss of collagen and bone supporting the tooth. In recent years, research has elucidated the contribution of host-microbe interaction to both disease initiation and disease progression. Epidemiological and clinical studies indicate variation in susceptibility to periodontal disease despite the long-term presence of the oral biofilm, in addition to increased susceptibility and greater severity of periodontal disease in patients with an impaired immune response. However, the immune response initiated by periodontal disease seems to be much broader. This review attempts to enlighten the various immune mechanisms involved in periodontal disease initiation and progression.