title: Effects of nicotine on bone during orthodontic tooth movement in male rats. Histological and immunohistochemical study.
abstract: OBJECTIVE
  To investigate the effects of nicotine on orthodontic tooth movement and accompanying histological and immunohistochemical changes in rats.
  
  
  METHODS
  An experimental study conducted at King Abdulaziz University, Jeddah, Saudi Arabia between 2013 and 2014. Thirty-two rats randomly divided into 4 groups. Three were experimental, received daily nicotine injections: group A: 0.37 mg/kg, group B: 0.57 mg/kg, and group C: 0.93 mg/kg. The control group  (group D) received a daily injection of 0.5 mL saline. All rats were subjected to 30 g of orthodontic force on the maxillary left first molars and incisors using a nickel-titanium closed-coil spring. The distance between the 2 teeth was assessed before and after 14 days of force application. Histological, immunohistochemical, and histomorphometric assessments were performed on sections from groups C and D.
  
  
  RESULTS
  Groups C (p less than 0.001) and D (p less than 0.001) showed the significantly greatest and least amounts of tooth movement . The results were statistically dose-dependent. Unbalanced resorption-apposition bone remodeling patterns and increased osteoclast cell distribution were observed in the nicotine group with significantly smaller percentages of bone surface areas mesially and distally (p less than 0.05). Immunohistochemical stains showed low alkaline phosphatase activity and intense tartrate-resistant acid phosphatase activity in the nicotine group.
  
  
  CONCLUSIONS
  Nicotine accelerated orthodontic tooth movement with unbalanced bone resorption and apposition patterns around the moving teeth.
authors.affiliation: Department of Orthodontics, Dammam Medical Complex, Ministry of Health, Dammam, Kingdom of Saudi Arabia. E-mail. dr_bakathir@hotmail.com.
authors.forename: Manal A
authors.initials: MA
authors.lastname: Bakathir
authors.forename: Amal I
authors.initials: AI
authors.lastname: Linjawi
authors.forename: Samia S
authors.initials: SS
authors.lastname: Omar
authors.forename: Ahad B
authors.initials: AB
authors.lastname: Aboqura
authors.forename: Ali H
authors.initials: AH
authors.lastname: Hassan
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D009970:Orthodontics; D051381:Rats; D017208:Rats, Wistar; D014087:Tooth Movement Techniques
chemical_list: D009538:Nicotine