title: Finite element analysis of rapid canine retraction through reducing resistance and distraction.
abstract: OBJECTIVE
  The aims of this study were to compare different surgical approaches to rapid canine retraction by designing and selecting the most effective method of reducing resistance by a three-dimensional finite element analysis.
  
  
  METHODS
  Three-dimensional finite element models of different approaches to rapid canine retraction by reducing resistance and distraction were established, including maxillary teeth, periodontal ligament, and alveolar. The models were designed to dissect the periodontal ligament, root, and alveolar separately. A 1.5 N force vector was loaded bilaterally to the center of the crown between first molar and canine, to retract the canine distally. The value of total deformation was used to assess the initial displacement of the canine and molar at the beginning of force loading. Stress intensity and force distribution were analyzed and evaluated by Ansys 13.0 through comparison of equivalent (von Mises) stress and maximum shear stress.
  
  
  RESULTS
  The maximum value of total deformation with the three kinds of models occurred in the distal part of the canine crown and gradually reduced from the crown to the apex of the canine; compared with the canines in model 3 and model 1, the canine in model 2 had the maximum value of displacement, up to 1.9812 mm. The lowest equivalent (von Mises) stress and the lowest maximum shear stress were concentrated mainly on the distal side of the canine root in model 2. The distribution of equivalent (von Mises) stress and maximum shear stress on the PDL of the canine in the three models was highly concentrated on the distal edge of the canine cervix. .
  
  
  CONCLUSIONS
  Removal of the bone in the pathway of canine retraction results in low stress intensity for canine movement. Periodontal distraction aided by surgical undermining of the interseptal bone would reduce resistance and effectively accelerate the speed of canine retraction.
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Xue
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Niansong
authors.initials: N
authors.lastname: Ye
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Tongji University School of Medicine, Shanghai Tenth People's Hospital, Department of Stomatology, Shanghai, P.R. China, Department of Stomatology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, P.R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Li
authors.affiliation: Xinjiang Medical University, First Affiliated Hospital, Department of Orthodontics, UrumqiXinjiang, P.R. China, Department of Orthodontics, First Affiliated Hospital of Xinjiang Medical University, Urumqi. Xinjiang, P.R. China.
authors.forename: Congbo
authors.initials: C
authors.lastname: Mi
authors.affiliation: Sichuan University, West China Hospital of Stomatology, Department of Orthodontics, State Key Laboratory of Oral Disease, ChengduSichuan, P.R. China, State Key Laboratory of Oral Disease, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, P.R. China.
authors.forename: Wenli
authors.initials: W
authors.lastname: Lai
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003481:Cuspid; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D006801:Humans; D008437:Maxilla / Q000601:surgery; D008954:Models, Biological; D010513:Periodontal Ligament / Q000601:surgery*; D012016:Reference Values; D015203:Reproducibility of Results; D014087:Tooth Movement Techniques / Q000379:methods*; D014092:Tooth Root / Q000601:surgery