title: The effect of caffeine on orthodontic tooth movement in rats.
abstract: OBJECTIVE
  to determine the effect of different doses of caffeine on orthodontic tooth movement (OTM) in rats.
  
  
  METHODS
  Forty male 250-300 g Sprague-Dawley rats were randomly divided into four groups of ten animals each and received 0 (control), 1 g/l, 2 g/l and 3 g/l caffeine in tap water for 3 days. Orthodontic appliances were ligated between the maxillary first molars and incisors on the 4th day of the study period. All rats were sacrificed after 2 weeks of treatment after which OTM was measured. Hematoxylin/eosin-stained sections of the molars were prepared and the mesial roots were examined for resorption-lacunae depth and osteoclast number. ANOVA was used for statistical analysis (P<0.05).
  
  
  RESULTS
  A significant decrease in OTM was observed only in the 2 g/l (P=0.043) and 3 g/l (P<0.01) caffeine-receiving rats compared to the control animals. Osteoclast counts and resorption-lacunae depths demonstrated significant differences between each of the caffeine groups and control rats (P<0.05). None of the variables showed significant differences between the caffeine groups (P>0.05).
  
  
  CONCLUSIONS
  According to our findings, one of the effects of caffeine consumption during orthodontic treatment in rats was decreased root resorption. Additionally, concentrations of 2 g/l and 3 g/l inhibited OTM which seems to be due to its influence on osteoclast numbers.
authors.affiliation: Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Shirazi
authors.affiliation: Private practice, Houston, Texas.
authors.forename: Hamed
authors.initials: H
authors.lastname: Vaziri
authors.affiliation: Orthodontic Resident, Department of Orthodontics, School of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Salari
authors.affiliation: Department of Oral and Maxillofacial Pathology, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Pouria
authors.initials: P
authors.lastname: Motahhari
authors.affiliation: Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Shahroo
authors.initials: S
authors.lastname: Etemad-Moghadam
authors.affiliation: Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Dehpour
keywords: Caffeine; Rats; Root resorption; Tooth movement