title: The effect of oral contraceptives on orthodontic tooth movement in rat.
abstract: BACKGROUND
  The purpose of this study was to investigate the effect of ethinyl estradiol/norgestrel - used in some oral contraceptives- on orthodontic tooth movement in Wistar rats.
  
  
  METHODS
  Forty eight female three-month old Wistar rats with an average weight of 250 ± 25 gr were divided into two experimental and control groups. One week prior to appliance insertion and during the appliance therapy period, 100 mcg/kg/day of ethinyl estradiol and 1 mg/kg/days of norgestrel were administered to the experimental group by gavage; meanwhile the control group received an equivalent volume of Sodium Chloride 0.9 % (Saline). Maxillary central incisors were tipped distally by insertion of springs exerting 30 g force. Two, seven and fourteen days after spring insertion animals were sacrificed. The mesioincisal distance between maxillary incisors were measured. Subsequently, histological sections were prepared for histomorphometric studies.
  
  
  RESULTS
  14 days after force application the orthodontic tooth movement was significantly lower in the experimental group (p<0.05). The number of osteoclasts were significantly lower in the experimental group 2, 7 and 14 days after spring insertion (p<0.05).
  
  
  CONCLUSIONS
  Ethinyl estradiol/norgestrel (oral contraceptives) can significantly decrease the amount of tooth movement in the linear phase.
authors.affiliation: Department of orthodontics, Faculty of dentistry, Urmia University of Medical Sciences, Urmia, Iran. dr_olyaee@yahoo.com
authors.forename: Pooya
authors.initials: P
authors.lastname: Olyaee
authors.forename: Behnam
authors.initials: B
authors.lastname: Mirzakouchaki
authors.forename: Kavoos
authors.initials: K
authors.lastname: Ghajar
authors.forename: Seyyed-Amir
authors.initials: SA
authors.lastname: Seyyedi
authors.forename: Majid
authors.initials: M
authors.lastname: Shalchi
authors.forename: Alireza
authors.initials: A
authors.lastname: Garjani
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Dadgar
mesh_terms: D000818:Animals; D003276:Contraceptives, Oral / Q000494:pharmacology*; D019304:Ethinyl Estradiol-Norgestrel Combination / Q000494:pharmacology*; D005260:Female; D051381:Rats; D017208:Rats, Wistar; D014087:Tooth Movement Techniques
chemical_list: D003276:Contraceptives, Oral; D019304:Ethinyl Estradiol-Norgestrel Combination