title: In vivo microcomputed tomography evaluation of rat alveolar bone and root resorption during orthodontic tooth movement.
abstract: OBJECTIVE
  To observe the real-time microarchitecture changes of the alveolar bone and root resorption during orthodontic treatment.
  
  
  METHODS
  A 10 g force was delivered to move the maxillary left first molars mesially in twenty 10-week-old rats for 14 days. The first molar and adjacent alveolar bone were scanned using in vivo microcomputed tomography at the following time points: days 0, 3, 7, and 14. Microarchitecture parameters, including bone volume fraction, structure model index, trabecular thickness, trabecular number, and trabecular separation of alveolar bone, were measured on the compression and tension side. The total root volume was measured, and the resorption crater volume at each time point was calculated. Univariate repeated measures analysis of variance with Bonferroni corrections were performed to compare the differences in each parameter between time points with significance level at P < .05.
  
  
  RESULTS
  From day 3 to day 7, bone volume fraction, structure model index, trabecular thickness, and trabecular separation decreased significantly on the compression side, but the same parameters increased significantly on the tension side from day 7 to day 14. Root resorption volume of the mesial root increased significantly on day 7 of orthodontic loading.
  
  
  CONCLUSIONS
  Real-time root and bone resorption during orthodontic movement can be observed in 3 dimensions using in vivo micro-CT. Alveolar bone resorption and root resorption were observed mostly in the apical third on day 7 on the compression side; bone formation was observed on day 14 on the tension side during orthodontic tooth movement.
authors.affiliation: Department of Orthodontics, Capital Medical University School of Stomatology, Beijing, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Ru
authors.forename: Sean Shih-Yao
authors.initials: SS
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Zhuang
authors.forename: Song
authors.initials: S
authors.lastname: Li
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Bai
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000648:ultrastructure; D000704:Analysis of Variance; D000818:Animals; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D010513:Periodontal Ligament / Q000000981:diagnostic imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology*; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000648:ultrastructure; D055114:X-Ray Microtomography