title: Immediately loaded mini screws: histological study of the effect of two different orthodontic tooth movement techniques.
abstract: The aim of this study was to assess histologically the bone changes around immediately loaded mini screws and whether there is a difference in those changes upon using corticotomy facilitated (CF) orthodontic tooth movement technique, in comparison to standard (S) orthodontic tooth movement technique.
  
  
  METHODS
  Six dogs, aged 6-9 months, were used in this study. Extraction of the maxillary second premolar and mini screw placement were done bilaterally in the maxilla. On the right (CF) side, corticotomy was performed. The first premolars were distalized against the mini screws with NiTi coil springs on both sides. The dogs were sacrificed weekly after orthodontic force application.
  
  
  RESULTS
  Histological analysis showed that osseous formation was progressive around the mini screw along the period of the study in both groups, although osseointegration was not found. There was a histological difference in the peri-screw bone between the two groups. In (S) side the bone formation started much earlier than the (CF) side.
  
  
  CONCLUSIONS
  During the six weeks period of this study the mini screws depended mainly on mechanical interlocking in their retention. The (CF) technique delayed the osseous bone formation around the mini screws in comparison to the (S) technique.
authors.affiliation: Orthodontic Department, Faculty of Oral and Dental Medicine, Cairo University, Egypt. monasfayed@yahoo.com
authors.forename: Mona Mohamed Salah
authors.initials: MM
authors.lastname: Fayed
authors.forename: Samah
authors.initials: S
authors.lastname: Mehanni
authors.forename: Nader Nabil
authors.initials: NN
authors.lastname: Elbokle
authors.forename: Yehia Ahmed
authors.initials: YA
authors.lastname: Mostafa
mesh_terms: D000818:Animals; D001863:Bone Screws; D003799:Dental Stress Analysis; D004285:Dogs; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016348:Osseointegration; D018709:Statistics, Nonparametric; D014087:Tooth Movement Techniques / Q000379:methods*