title: Three-dimensional morphology of root and alveolar trabecular bone during tooth movement using micro-computed tomography.
abstract: OBJECTIVE
  To investigate the effects of force magnitude on three-dimensional alveolar trabecular bone structure and root resorption.
  
  
  METHODS
  Twenty-two 11-week-old Sprague Dawley rats were randomly assigned to two groups that received a mesially directed orthodontic force to the upper right first molars at different magnitudes of force, 30 g or 100 g, for 2 weeks. The contralateral molars served as controls. The teeth and alveolar bone around the teeth were dissected from the sacrificed animals and were scanned with micro-computed tomography (CT). Structural properties of the trabecular bone and resorption crater volume on the mesial roots of the maxillary first molars were analyzed.
  
  
  RESULTS
  The bone volume fraction of the 30 g group and the 100 g group increased significantly in both groups, and trabecular separation of the 100 g group decreased significantly compared with controls (P < .05). The total root resorption volume in all experimental groups and the resorption volume of the lower distal surface in the 100 g group increased significantly compared with controls (P < .01). The volume of the upper mesial root surface in the 30 g group increased significantly compared with the 100 g group and controls (P < .05).
  
  
  CONCLUSIONS
  The alveolar trabecular bone was denser after orthodontic force was applied for 14 days. The effects of 30 g and 100 g orthodontic forces on root resorption were different at the upper mesial and lower distal surfaces of the mesial roots of maxillary first molars.
authors.affiliation: Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhuang
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Bai
authors.forename: Xianying
authors.initials: X
authors.lastname: Meng
mesh_terms: D000539:Alveolar Process / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D000818:Animals; D015519:Bone Density; D003799:Dental Stress Analysis; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012391:Root Resorption / Q000209:etiology; D014087:Tooth Movement Techniques / Q000009:adverse effects / Q000295:instrumentation; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography