title: Smoking cessation may present a positive impact on mandibular bone quality and periodontitis-related bone loss: a study in rats.
abstract: BACKGROUND
  It has been previously shown that cigarette smoke inhalation (CSI) enhances bone loss in ligature-induced periodontitis. In this study, the hypothesis that the interruption of smoke exposure would reverse the impact of CSI on mandibular bone quality and periodontitis-related bone loss was tested.
  
  
  METHODS
  Fifty-three Wistar rats were randomly assigned to one of the following groups: group 1: control, N = 16; group 2: 83 days of CSI prior to ligature placement, N = 17; or group 3: 90 days of CSI before and 60 days after ligature placement, N = 20. Animals were sacrificed 60 days after ligature placement, the jaws removed and immediately radiographed for photodensitometry analysis. Bone loss was histometrically evaluated.
  
  
  RESULTS
  CSI did not affect unligated sites in either condition (P >0.05); however, smoke inhalation during the whole experimental period significantly enhanced bone loss in ligated teeth (P < 0.05). Moreover, similar levels of bone loss were observed for ligated teeth between the control and cessation groups (0.90 +/- 0.33 mm(2); 0.96 +/- 0.32 mm(2); 1.64 +/- 0.65 mm(2); groups 1, 2 and 3, respectively). Radiographically, continuous exposure to cigarette smoke promoted a significantly reduced bone density (1.74 +/- 0.38 aluminum equivalence [Al eq]; 1.74 +/- 0.14 Al eq; and 0.68 +/- 0.10 Al eq for groups 1, 2, and 3, respectively).
  
  
  CONCLUSIONS
  Within the limits of the present investigation, it can be assumed that CSI may enhance bone loss in ligature-induced periodontitis, and negatively impact mandibular bone quality. Additionally, smoke exposure cessation seems to reverse its impact on mandibular bone, and, therefore, may be of clinical relevance.
authors.affiliation: Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, University of Campinas, São Paulo, Brazil.
authors.forename: João B
authors.initials: JB
authors.lastname: César-Neto
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Benatti
authors.forename: Francisco Haiter
authors.initials: FH
authors.lastname: Neto
authors.forename: Antonio W
authors.initials: AW
authors.lastname: Sallum
authors.forename: Enilson A
authors.initials: EA
authors.lastname: Sallum
authors.forename: Francisco H
authors.initials: FH
authors.lastname: Nociti
mesh_terms: D015502:Absorptiometry, Photon; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density; D008026:Ligation; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology; D010518:Periodontitis / Q000000981:diagnostic imaging / Q000209:etiology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012907:Smoking / Q000009:adverse effects; D016540:Smoking Cessation; D018709:Statistics, Nonparametric