TOBACCO AND SMOKING - ENVIRONMENTAL-FACTORS THAT MODIFY THE HOST RESPONSE (IMMUNE-SYSTEM) AND HAVE AN IMPACT ON PERIODONTAL HEALTH

This review summarizes the current data on the effects of smoking and tobacco on the immune system and its potential impact on periodontal h ealth. Smokers are 2.5-6 times more likely to develop periodontal dise ase than non-smokers, and there is evidence for a direct correlation b etween the number of cigarettes smoked and the risk of developing dise ase. Tobacco users also tend to exhibit increased severity of periodon tal disease. Direct correlations between tobacco use and increased att achment loss and pocket depth and reduced bone crest height have been reported. Although the correlation between tobacco use and periodontal disease is quite strong, the role of tobacco in the pathogenesis of p eriodontal disease is uncertain. Recent studies indicate that one pote ntial mechanism is that tobacco use exacerbates periodontal disease be cause it alters the immune response to periodontal pathogens. Indeed, smokers exhibit increased numbers of peripheral blood mononuclear phag ocytes which appear to be functionally compromised. Inadequate phagocy te activity could reduce the clearance of pathogens from the oral cavi ty and thereby facilitate the development of periodontal disease. Toba cco-exposed B- and T-lymphocytes exhibit reduced proliferative capacit ies which could limit the production of protective immunoglobulins aga inst oral pathogens.The risk factors for periodontal disease can be br oadly classified as genetic, environmental, host-response factors, and host-related factors such as age. Tobacco, an environmental factor, u ndermines the host response and may facilitate the development and pro gression of periodontal disease. This review highlights the inter-rela tedness of two of the risk factors associated with periodontal disease .