title: Mechanisms of action of environmental factors--tobacco smoking.
abstract: OBJECTIVE
  To review the potential biological mechanisms underlying the effects of tobacco smoking on periodontitis.
  
  
  RESULTS
  Smoking has major effects on the host response, but there are also a number of studies that show some microbiological differences between smokers and non-smokers. Smoking has a long-term chronic effect on many important aspects of the inflammatory and immune responses. Histological studies have shown alterations in the vasculature of the periodontal tissues in smokers. Smoking induces a significant systemic neutrophilia, but neutrophil transmigration across the periodontal microvasculature is impeded. The suppression of neutrophil cell spreading, chemokinesis, chemotaxis and phagocytosis have been described. Protease release from neutrophils may be an important mechanism in tissue destruction. Tobacco smoke has been found to affect both cell-mediated immunity and humoral immunity. Research on gingival crevicular fluid has demonstrated that there are lower levels of cytokines, enzymes and possibly polymorphonuclear cells in smokers. In vitro studies have shown detrimental effects of nicotine and some other tobacco compounds on fibroblast function, including fibroblast proliferation, adhesion to root surfaces and cytotoxicity.
  
  
  CONCLUSIONS
  Tobacco smoking has widespread systemic effects, many of which may provide mechanisms for the increased susceptibility to periodontitis and the poorer response to treatment.
authors.affiliation: King's College London, Guy's Hospital Campus, London Bridge, London SE1 9RT, UK. richard.m.palmer@kcl.ac.uk
authors.forename: Richard M
authors.initials: RM
authors.lastname: Palmer
authors.forename: Ron F
authors.initials: RF
authors.lastname: Wilson
authors.forename: Adam S
authors.initials: AS
authors.lastname: Hasan
authors.forename: David A
authors.initials: DA
authors.lastname: Scott
mesh_terms: D002448:Cell Adhesion / Q000187:drug effects; D004781:Environmental Exposure / Q000009:adverse effects; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000098:blood supply / Q000187:drug effects; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology; D010518:Periodontitis / Q000209:etiology*; D010519:Periodontium / Q000098:blood supply / Q000382:microbiology; D012907:Smoking / Q000009:adverse effects*; D014026:Nicotiana