title: [Biomechanical study of "mandible-temporomandibular joint" under different loading angles with forsus].
abstract: OBJECTIVE
  To identify the best loading angle with Forsus for mandible-temporomandibular joint.
  
  
  METHODS
  The changes in stress, displacement and rotation of "mandible-temporomandibular joint" were tested under -30 degrees, -15 degrees, 0 degrees, 15 degrees and 25 degrees of loading angles using a primary three dimensional finite element model.
  
  
  RESULTS
  From 0 degrees to 25 degrees, with the increases of loading angles the displacement gradually increased. The maximum displacement occurred at chin, with 1.692 mm, 3.456 mm and 4.630 mm displacement under 0 degrees, 15 degrees and 25 degrees respectively. The maximum displacement occurred at the alveolar ridge under -15 degrees loading, which was 0.069 mm. No special stress concentration region was identified. The displacements from infradentale to pogonion gradually increased under all conditions except for the -15 degrees loading. With the loading angles deviated from the baseline farther, the porrect displacements of chin and the counterclockwise rotation became more obvious.
  
  
  CONCLUSIONS
  The loading angles of Forsus appliance should be controlled between 0 degrees and 25 degrees.
authors.affiliation: Department of Stomatology, Affiliated Hospital of North Sichuan Medical College, Nanchong 637000, China.
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Li
authors.forename: Jin-lin
authors.initials: JL
authors.lastname: Song
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Feng
authors.initials: F
authors.lastname: Deng
authors.forename: Na
authors.initials: N
authors.lastname: Li
mesh_terms: D001696:Biomechanical Phenomena; D002648:Child; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008334:Mandible / Q000503:physiopathology*; D017289:Orthodontic Appliances, Functional; D009971:Orthodontics, Corrective / Q000379:methods*; D013704:Temporomandibular Joint / Q000503:physiopathology*