Inflammatory periodontal disease is one of the most common diseases of mankind. Gingival inflammation is widespread, but advanced periodontitis is limited to relatively small groups of population. Microbial plaque deposits at the dentogingival interface initiate gingivitis. Progression to periodontitis is modified by several environmental, behavioral, biological and healthcare variables. The purpose of this paper is to summarize the available information on the influence of risk factors on progression of periodontitis. 

Keywords: Inflammatory disease; Microbial deposit; Genetics; Smoking; Diabetes; Socioeconomic factor; HIV.