title: [A 3-dimensional finite element analysis of displacement of maxillary first molar on mesial movement in lingual orthodontics].
abstract: OBJECTIVE
  To analyze the displacement of maxillary first molar on mesial movement by lingual technique with the finite element method,and compare with that by labial technique.
  
  
  METHODS
  The finite element model was built using the advanced 3-dimensional laser scanning, comprising a maxillary first molar, periodontal ligament, alveolar bone, and a lingual or buccal tube. Different kinds of loads were applied at a point of the lingual or buccal tube separately. By finite element method,the displacement of maxillary first molar was calculated and analyzed.
  
  
  RESULTS
  When the mesial force was applied to the maxillary first molar,the tooth was tipped mesially, rotated distally and lingually by lingual technique. By the labial technique,the tooth was tipped mesially, rotated distally and buccally. The degree of tipping and rotation by labial technique was bigger than that by lingual technique. By labial technique, Mt/F=8.1:1,Mr/F=8:1. By lingual technique, Mt/F=6.9:1,Mr/F=7.1:1. When the tooth moved bodily,the displacement of lingual technique was larger than that by labial technique.
  
  
  CONCLUSIONS
  When the maxillary first molar moved bodily toward mesial direction, lingual orthodontics is more efficient than labial orthodontics.
authors.affiliation: Dental Disease Prevention and Treatment Hospital of Shaoxing, Shaoxing, Zhejiang Province, China. LLL9316@163.com
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Wang
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.forename: Shu-Yu
authors.initials: SY
authors.lastname: Wang
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
mesh_terms: D020342:Finite Element Analysis; D006801:Humans; D008963:Molar; D009967:Orthodontic Appliances; D009970:Orthodontics; D010513:Periodontal Ligament; D014087:Tooth Movement Techniques