title: Stress distribution and displacement analysis during an intermaxillary disjunction--a three-dimensional FEM study of a human skull.
abstract: The goal of this study was to contribute to an understanding of how much expansion force is needed during a maxillary expansion (ME) and where bony reaction takes place. A finite element (FE) model of a dry human male skull was generated from CT scans. The FE model, which consists of cortical and cancellous bone and teeth, was loaded with the same force magnitudes, directions and working points as in rapid maxillary expansion (RME). A three-dimensional finite element stress analysis (FESA) of the forces and displacement was performed. The highest stress was observed in the maxilla in the region where the forces were applied, and spreads more or less throughout almost the whole frontal skull structures. The displacement distribution which causes stress in the skull is highly dependant on the thickness of the bone and its structure. All areas with high compressive and tensile stress are exactly the regions which determine the maximal amount of force to be used during the maxillary expansion and should be examined in case of any complication during a patient's treatment. Regions with significant compressive and tensile stress are the regions observed to have an increase in cellular activity. Further simulations with a given displacement (0.5mm) showed that displacement simulations need extra caution otherwise they will lead to very high forces which are not realistic in an orthodontic treatment.
authors.affiliation: Department of Orthodontics ZMK 4, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Baden-Wuerttemberg, Germany. andrew.boryor@uni-ulm.de
authors.forename: Andrew
authors.initials: A
authors.lastname: Boryor
authors.forename: Martin
authors.initials: M
authors.lastname: Geiger
authors.forename: Ansgar
authors.initials: A
authors.lastname: Hohmann
authors.forename: Arthur
authors.initials: A
authors.lastname: Wunderlich
authors.forename: Christian
authors.initials: C
authors.lastname: Sander
authors.forename: Franz
authors.initials: F
authors.lastname: Martin Sander
authors.forename: Franz Günter
authors.initials: FG
authors.lastname: Sander
mesh_terms: D000328:Adult; D003198:Computer Simulation; D003799:Dental Stress Analysis / Q000379:methods*; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008437:Maxilla / Q000502:physiology*; D008954:Models, Biological; D010155:Palatal Expansion Technique; D012886:Skull / Q000502:physiology; D013314:Stress, Mechanical