title: Micro-computerized tomography analysis of alveolar bone loss in ligature- and nicotine-induced experimental periodontitis in rats.
abstract: OBJECTIVE
  Nicotine reportedly is a risk factor for periodontitis, but accurate data regarding nicotine-induced alveolar bone loss is lacking. The aim of this study was to quantitatively assess alveolar bone loss in ligature- and nicotine-induced periodontitis in rats using micro-computerized tomography (micro-CT).
  
  
  METHODS
  Thirty-six adult male rats were treated by placing silk ligatures around the cervixes of the right second maxillary molar; the contralateral tooth was untreated. After ligation, the animals were randomly divided into three groups: group A received intraperitoneal injections of saline solution, group B received 0.83 mg of nicotine/kg/d, and group C received 1.67 mg of nicotine/kg/d. Six animals in each group were killed on days 14 and 28 after ligature placement, and then micro-CT examinations were conducted.
  
  
  RESULTS
  In all groups, bone mineral density (BMD), bone volume fraction (BVF), trabecular number (Tb.N) and trabecular thickness (Tb.Th) values of the ligated sides were significantly lower than those of the unligated sides (p < 0.001), whereas alveolar bone height loss (ABHL) and trabecular separation (Tb.Sp) of the ligated sides were significantly higher than those of the unligated sides (p < 0.001). Compared with the control group, nicotine administration increased the ABHL value and decreased the BMD, BVF and Tb.Th values of both sides in a dose-dependent manner (p < 0.05).
  
  
  CONCLUSIONS
  Our results confirmed that ligature could cause significant loss in the trabecula of alveolar bone, and daily administration of nicotine resulted in further bone loss and microstructure deterioration.
authors.affiliation: Department of Pediatric Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China Department of Osteology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Y-F
authors.initials: YF
authors.lastname: Liu
authors.forename: L-A
authors.initials: LA
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: L-Y
authors.initials: LY
authors.lastname: Wen
authors.forename: X-J
authors.initials: XJ
authors.lastname: Wang
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D000818:Animals; D015519:Bone Density; D055113:Chronic Periodontitis / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D004305:Dose-Response Relationship, Drug; D008026:Ligation; D008297:Male; D009538:Nicotine / Q000633:toxicity*; D018722:Nicotinic Agonists / Q000633:toxicity*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine