Periodontal diseases are inflammatory diseases in which microbial etiologic factors induce a series of host responses that mediate inflammatory events. In susceptible individuals dysregulation of inflammatory and immune pathways leads to chronic inflammation tissue destruction and disease. Physiologic inflammation is a well-orchestrated network of cells mediators and tissues. It is very important to consider the inflammatory / immune response as a whole rather than many different modules working separately.As disease appears to be the result of loss of regulation and a failure to return to homeostasis it is important to achieve a more complete understanding of the molecular and cellular events in this complex system.