title: [A structural mechanics study with human maxillary premolar].
abstract: OBJECTIVE
  To evaluate the stress distribution and offset of dental and periodontal tissues imposed by changes in inner diameter of pulp cavity.
  
  
  METHODS
  Six models of maxillary second bicuspid tooth with different inner diameter of pulp cavity were established, including: (1) calcificated pulp without pulp chamberi (2) mostly calcificated pulp chamber with inward reduction of 0. 5 mm in normal pulp cavity; (3) initially calcificated pulp chamber with inward reduction of 0.25 mm in normal pulp cavity; (4) normal pulp cavity; (5) initially absorbed pulp chamber with outward expansion of 0.25 mm in normal pulp cavity; (6) mostly absorbed pulp chamber with outward expansion of 0.5 mm in normal pulp cavity. Vertical and oblique forces with 160 N were loaded on the central fossa, respectively, in order to calculate the stress distribution of dental and periodontal tissues and the maximum incipient offset of the teeth.
  
  
  RESULTS
  With loaded vertical and oblique forces on central fossa, increased stress distribution of periodontal tissues and maximum incipient offset of teeth were found in all of the models, which increased with the increase of pulp cavity.
  
  
  CONCLUSIONS
  The change in inner diameter of pulp cavity has an impact on the stress distribution of periodontal tissues and maximum incipient offset of the second upper bicuspid teeth.
authors.affiliation: Department of Prosthodontics, West China Stamatelosical Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Jun-xian
authors.initials: JX
authors.lastname: Qiu
authors.forename: Xi
authors.initials: X
authors.lastname: Zhao
authors.forename: Xin-min
authors.initials: XM
authors.lastname: Chen
authors.forename: Xiao-nan
authors.initials: XN
authors.lastname: Zhang
authors.forename: Qing-lin
authors.initials: QL
authors.lastname: Men
authors.forename: Chao
authors.initials: C
authors.lastname: Xu
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology* / Q000502:physiology*; D001696:Biomechanical Phenomena; D003782:Dental Pulp / Q000033:anatomy & histology*; D020342:Finite Element Analysis; D006801:Humans; D008437:Maxilla; D013314:Stress, Mechanical