title: Enhancement of orthodontic anchorage and retention by the local injection of strontium: An experimental study in rats.
abstract: OBJECTIVE
  To examine the clinical and histological effects of locally injected strontium on the anchoring unit of a rat model of an experimental relapsed tooth movement.
  
  
  METHODS
  Thirty-six 10-week-old male Wister rats were randomly divided into two groups of 18 animals that were then randomly divided into three subgroups of six animals corresponding to three observation periods: T1 = 1 week, T2 = 2 weeks, and T3 = 3 weeks. In the first experiment, both the right and left maxillary first molars were moved buccally with a standardized expansive spring. Strontium chloride solution was injected every 2 days into the subperiosteal area buccal to the left maxillary first molar (the experimental side). The right-sided first molar was injected with distilled water as a control. In the second experiment, maxillary first molars were moved buccally with the spring. After 3 weeks, the spring was removed. Two days before the spring removal, strontium chloride was injected into the palatal side of left-sided maxillary first molar and distilled water was injected into the palatal side of the right-sided maxillary first molar as in experiment 1.
  
  
  RESULTS
  At the end of the experimental period, significant levels of inhibition were noted in terms of both tooth movement and relapse movement in strontium-injected sides. Histological examinations showed that strontium enhanced the number of osteoblasts and reduced the number of osteoclasts.
  
  
  CONCLUSIONS
  The local injection of strontium can inhibit the degree of experimental and relapsed tooth movement in a rat model.
authors.affiliation: College of Dentistry, AL_Iraqia University, Iraq.
authors.forename: Munad J
authors.initials: MJ
authors.lastname: Al-Duliamy
authors.affiliation: Department of Orthodontics, College of Dentistry, University of Baghdad, Iraq.
authors.forename: Nidhal H
authors.initials: NH
authors.lastname: Ghaib
authors.affiliation: Department of Oral Diagnosis, College of Dentistry, University of Baghdad, Iraq.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Kader
authors.affiliation: Department of Oral Diagnosis, College of Dentistry, University of Baghdad, Iraq.
authors.forename: Bashar H
authors.initials: BH
authors.lastname: Abdullah
keywords: Orthodontic anchorage; Retention; Strontium