title: Three-dimensional finite element analysis of occlusal stress distribution in the human skull with premolar extraction.
abstract: OBJECTIVE
  To analyze the effect of orthodontic treatment with premolar extraction on the stress distribution of the occlusal force in the human skull.
  
  
  METHODS
  A three-dimensional finite element (3D FE) model was constructed based on computed tomography scan data, and it served as the pretreatment model. For the extraction model simulating postorthodontic occlusion, the first premolar was removed in the pretreatment model, and the anterior and posterior segments were repositioned. Stress distribution was evaluated by 3D FE analysis in both models under the simulation of 1000 N for occlusal forces and 400 N for masseter muscle force.
  
  
  RESULTS
  The occlusal stresses were concentrated at the alveolar bone near the teeth, the infrazygomatic crest, the frontal process, the temporal process of the zygomatic bone, the infraorbital rim, the pyriform aperture region, and the pterygoid plate in both models. The von Mises stress at the pterygoid plate area was lower in the extraction model (3.53 MPa) than in the pretreatment model (5.57 MPa), while the stress at the frontal process of the maxilla was higher in the extraction model (2.32 MPa) than in the pretreatment model (2.16 MPa).
  
  
  CONCLUSIONS
  The results indicated that the occlusal forces were transferred through the maxillonasal, maxillozygomatic, and maxillopterygoid stress trajectories and that stress distribution moved more "forward" with the orthodontic treatment with premolar extraction.
authors.affiliation: Associate Professor, Department of Orthodontics, College of Dentistry, Gangneung-Wonju National University, Gangneung, South Korea.
authors.forename: Dong-Soon
authors.initials: DS
authors.lastname: Choi
authors.forename: Bong-Kuen
authors.initials: BK
authors.lastname: Cha
authors.forename: Insan
authors.initials: I
authors.lastname: Jang
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Kang
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000601:surgery; D001732:Bite Force; D003766:Dental Occlusion; D003799:Dental Stress Analysis / Q000379:methods*; D005260:Female; D020342:Finite Element Analysis; D005624:Frontal Bone / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008406:Masseter Muscle / Q000502:physiology; D008437:Maxilla / Q000502:physiology; D008953:Models, Anatomic; D013701:Temporal Bone / Q000502:physiology; D014081:Tooth Extraction; D014087:Tooth Movement Techniques; D015050:Zygoma / Q000502:physiology