title: A comparative study on the effect of nicotine administration and cigarette smoke inhalation on bone healing around titanium implants.
abstract: BACKGROUND
  A series of isolated studies has focused on the influence of smoking on bone around titanium implants. This study proposes to investigate the impact of two conditions, i.e., nicotine administration and cigarette smoke inhalation, on the healing around implants.
  
  
  METHODS
  Forty-five Wistar rats were used. After anesthesia, the tibiae surface was exposed and a screw-shaped titanium implant was placed bilaterally. The animals were randomly assigned to one of the following groups: Group 1: control, n = 19; Group 2: intermittent cigarette smoke inhalation, n = 15; and Group 3: subcutaneous administration of nicotine (3 mg/kg) twice daily, n = 11. After 60 days, the animals were sacrificed. The degree of bone-to-implant contact (BIC) and the bone area (BA) within the limits of the threads of the implant were measured in the cortical (zone A) and cancellous bone (zone B) areas.
  
  
  RESULTS
  In zone A, cigarette smoke presented a significant negative influence on BIC and BA (Kruskal-Wallis test, P < 0.05). In contrast, the administration of nicotine did not influence either parameter (P > 0.05). In zone B, cigarette smoke inhalation also resulted in a decreased percentage of BIC compared to the control group (P < 0.05). In addition, the BA was significantly decreased in groups 2 and 3 when compared to controls (P > 0.05).
  
  
  CONCLUSIONS
  The negative impact of smoking on implant outcomes may be related to more than one molecule present in the cigarette smoke and nicotine seems to partially contribute, especially in the cancellous bone.
authors.affiliation: Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, UNICAMP, Piracicaba, São Paulo, Brazil.
authors.forename: João B
authors.initials: JB
authors.lastname: César-Neto
authors.forename: Poliana M
authors.initials: PM
authors.lastname: Duarte
authors.forename: Enilson A
authors.initials: EA
authors.lastname: Sallum
authors.forename: Deise
authors.initials: D
authors.lastname: Barbieri
authors.forename: Heitor
authors.initials: H
authors.lastname: Moreno
authors.forename: Francisco H
authors.initials: FH
authors.lastname: Nociti
mesh_terms: D000818:Animals; D003367:Cotinine / Q000097:blood / Q000633:toxicity; D020007:Implants, Experimental; D008297:Male; D009525:Niacin / Q000097:blood / Q000633:toxicity*; D009538:Nicotine / Q000097:blood / Q000633:toxicity*; D016348:Osseointegration / Q000187:drug effects*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution; D009525:Niacin; D009538:Nicotine; D003367:Cotinine