title: Serum, saliva, and GCF concentration of RANKL and osteoprotegerin in smokers versus nonsmokers with chronic periodontitis.
abstract: BACKGROUND
  The role of host response in periodontitis pathogenesis is confirmed, and it is well established that immune response plays a major role in the alveolar bone destruction. In the investigation of these responses, the role of receptor activator of the nuclear factor-kB ligand (RANKL)-osteoprotegerin (OPG) system is the most promising. Smoking can affect the RANKL-OPG system in a manner that will further enhance bone loss in periodontitis. The aim of this study is to assess the serum, saliva, and gingival crevicular fluid (GCF) concentration of RANKL and OPG in smoker versus nonsmoker untreated chronic periodontitis (CP) patients.
  
  
  METHODS
  Thirty-nine subjects were included in the present cross-sectional study: 29 systemically healthy CP male patients (15 smokers, 14 nonsmokers) and 10 systemically and periodontally healthy nonsmoker male subjects. Serum, GCF, and whole saliva samples were obtained from the subjects. The enzyme-linked immunosorbent assay (ELISA) kits were used for assaying the concentrations of RANKL and OPG in the samples. The one-way analysis of variance (ANOVA) test and the least significant difference (LSD) post hoc test were utilized to compare differences between the groups.
  
  
  RESULTS
  RANKL and OPG concentrations in saliva, serum, and GCF did not show any significant difference among all groups (P > 0.05). Salivary RANKL/OPG ratios were significantly higher in the nonsmoker CP group than in the healthy control group (P > 0.05) but they were not statistically significant among smoker periodontitis patients.
  
  
  CONCLUSIONS
  The salivary RANKL/OPG ratio was higher in nonsmokers with periodontitis in comparison with smoker periodontitis patients.
authors.affiliation: Department of Periodontics, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Parichehr
authors.initials: P
authors.lastname: Behfarnia
authors.affiliation: Department of Oral Public Health, Torabinejad Dental Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Saied-Moallemi
authors.affiliation: Department of Physiology, Applied Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Shaghayegh Haghjooy
authors.initials: SH
authors.lastname: Javanmard
authors.affiliation: Department of Periodontics, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Roohollah
authors.initials: R
authors.lastname: Naseri
keywords: Gingival crevicular fluid; OPG; RANKL; periodontitis; saliva; serum; smoking