Mohsen Shirazi - Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
Hamed Vaziri - Private practice, Houston, Texas
Behzad Salari - Orthodontic Resident, Department of Orthodontics, School of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran
Pouria Motahhari - Department of Oral and Maxillofacial Pathology, Tehran University of Medical Sciences, Tehran, Iran
Shahroo Etemad-Moghadam - Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
Ahmad Reza Dehpour - Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran

Objective(s): to determine the effect of different doses of caffeine on orthodontic tooth movement (OTM) in rats. Materials and Methods: Forty male ۲۵۰-۳۰۰ g Sprague-Dawley rats were randomly divided into four groups of ten animals each and received ۰ (control), ۱ g/l, ۲ g/l and ۳ g/l caffeine in tap water for ۳ days. Orthodontic appliances were ligated between the maxillary first molars and incisors on the ۴th day of the study period. All rats were sacrificed after ۲ 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<۰.۰۵). Results: A significant decrease in OTM was observed only in the ۲ g/l (P=۰.۰۴۳) and ۳ g/l (P<۰.۰۱) 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<۰.۰۵). None of the variables showed significant differences between the caffeine groups (P>۰.۰۵). Conclusion: According to our findings, one of the effects of caffeine consumption during orthodontic treatment in rats was decreased root resorption. Additionally, concentrations of ۲ g/l and ۳ g/l inhibited OTM which seems to be due to its influence on osteoclast numbers.

Caffeine, Rats, root resorption, Tooth movement