title: Effects of local osteoprotegerin gene transfection on orthodontic root resorption during retention: an in vivo micro-CT analysis.
abstract: OBJECTIVE
  External root resorption (ERR) is a serious complication of orthodontic treatment. Aim of this study was to evaluate the effects of local osteoprotegerin (OPG) gene transfection on ERR during retention.
  
  
  METHODS
  Eighteen 6-week-old male Wistar rats were divided into three groups. All the rats were subjected to 2 weeks of orthodontic tooth movement followed by a 2-week retention period. During retention, the three groups of rats received local OPG gene transfection (OPG transfection group, n=6), mock vector transfection (mock group, n=6), or no injections (control group, n=6). ERR of all three groups was evaluated with in vivo micro-CT analysis at three different time points: baseline, the last day of orthodontic tooth movement, and the last day of retention.
  
  
  RESULTS
  In the OPG transfection group, there was no significant difference between ERR at the baseline and ERR on the last day of retention. By the last day of retention, the repair ratio of ERR in the OPG transfection group was statistically higher in relation to the repair ratio of the other groups (p<0.001).
  
  
  CONCLUSIONS
  The results indicated that local OPG gene transfection significantly enhanced the repair of ERR during retention. Local OPG gene transfection might therefore be a useful tool for ERR repair during retention.
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: N
authors.initials: N
authors.lastname: Zhao
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Kanzaki
authors.forename: W
authors.initials: W
authors.lastname: Liang
authors.forename: J
authors.initials: J
authors.lastname: Ni
authors.forename: J
authors.initials: J
authors.lastname: Lin
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology; D000818:Animals; D015519:Bone Density / Q000235:genetics / Q000502:physiology; D016723:Bone Remodeling / Q000235:genetics / Q000502:physiology; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000473:pathology; D018704:Orthodontic Retainers; D009969:Orthodontic Wires; D053244:Osteoprotegerin / Q000235:genetics*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012391:Root Resorption / Q000235:genetics / Q000628:therapy*; D029082:Sendai virus / Q000235:genetics; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000295:instrumentation; D014162:Transfection / Q000379:methods*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D053244:Osteoprotegerin; C506032:Tnfrsf11b protein, rat