title: Impact of smoking on experimental gingivitis. A clinical, microbiological and immunological prospective study.
abstract: OBJECTIVE
  The present study assessed the effect of smoking on clinical, microbiological and immunological parameters in an experimental gingivitis model.
  
  
  METHODS
  Twenty-four healthy dental students were divided into two groups: smokers (n = 10); and nonsmokers (n = 14). Stents were used to prevent biofilm removal during brushing. Visible plaque index (VPI) and gingival bleeding index (GBI) were determined 5- on day -7 (running phase), baseline, 21 d (experimental gingivitis) and 28 d (resolution phase). Supragingival biofilm and gingival crevicular fluid were collected and assayed by checkerboard DNA-DNA hybridization and a multiplex analysis, respectively. Intragroup comparison was performed by Friedman and Dunn's multiple comparison tests, whereas the Mann-Whitney U-test was applied for intergroup analyses.
  
  
  RESULTS
  Cessation of oral hygiene resulted in a significant increase in VPI, GBI and gingival crevicular fluid volume in both groups, which returned to baseline levels 7 d after oral hygiene was resumed. Smokers presented lower GBI than did nonsmokers (p < 0.05) at day 21. Smokers had higher total bacterial counts and higher proportions of red- and orange complex bacteria, as well as lower proportions of Actinomyces spp., and of purple- and yellow-complex bacteria (p < 0.05). Furthermore, the levels of key immune-regulatory cytokines, including interleukin (IL)-8, IL-17 and interferon-γ, were higher in smokers than in nonsmokers (p < 0.05).
  
  
  CONCLUSIONS
  Smokers and nonsmokers developed gingival inflammation after supragingival biofilm accumulation, but smokers had less bleeding, higher proportions of periodontal pathogens and distinct host-response patterns during the course of experimental gingivitis.
authors.affiliation: Division of Periodontics, Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: D C
authors.initials: DC
authors.lastname: Peruzzo
authors.affiliation: Private practice, São Paulo, Brazil.
authors.forename: J H
authors.initials: JH
authors.lastname: Gimenes
authors.affiliation: Division of Periodontics, Department of Prosthodontics and Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
authors.forename: T
authors.initials: T
authors.lastname: Taiete
authors.affiliation: Department of Periodontics, Paulista University, São Paulo, Brazil.
authors.forename: R C V
authors.initials: RC
authors.lastname: Casarin
authors.affiliation: Department of Periodontics, Guarulhos University, São Paulo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Feres
authors.affiliation: Division of Periodontics, Department of Prosthodontics and Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
authors.forename: E A
authors.initials: EA
authors.lastname: Sallum
authors.affiliation: Division of Periodontics, Department of Prosthodontics and Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Casati
authors.affiliation: Department of Pediatric Dentistry, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
authors.forename: K R
authors.initials: KR
authors.lastname: Kantovitz
authors.affiliation: Division of Periodontics, Department of Prosthodontics and Periodontics, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
authors.forename: F H
authors.initials: FH
authors.lastname: Nociti
mesh_terms: D018441:Biofilms / Q000254:growth & development; D016022:Case-Control Studies; D016207:Cytokines / Q000032:analysis; D003774:Dental Plaque Index; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry; D005891:Gingivitis / Q000209:etiology* / Q000276:immunology / Q000382:microbiology; D006801:Humans; D008297:Male; D010512:Periodontal Index; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D016207:Cytokines
keywords: experimental gingivitis; gingivitis; risk factors; smoking