title: Comparison of five different fixation techniques of sagittal split ramus osteotomy using three-dimensional finite elements analysis.
abstract: The aim of this study was to compare the mechanical stress over hemimandible substrate and hardware after sagittal split ramus osteotomy (SSRO) fixed with five different techniques using three-dimensional (3D) finite element analysis. A 3D finite element model of a hemimandible was created and a 5mm advancement SSRO was simulated on a computer model. The model was fixed with five different techniques: 3 linear 60° screw arrangement; 3 linear 90° screw arrangement; 3 inverted L screw arrangement; 1 conventional miniplate; and 1 locking miniplate with four monocortical screws. Load was applied until 3mm displacement was reached and the results were compared with previous mechanical and photoelastic tests, thus analysing the mechanical stresses developed in the proximity of miniplates and screws and within the fixation system itself. The maximum principal stress values demonstrate a lower mechanical stress rate in bone and in the fixation system with the inverted L arrangement, followed by the linear 90° and linear 60° arrangements. The locking miniplate/screw system presented lower maximum principal stress and better stress distribution compared with the conventional system. Under the conditions tested, the reversed L arrangement provided the most favourable stress dissipation behaviour.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Piracicaba Dental School, State University of Campinas (Unicamp), Brazil. fabio.sato@fop.unicamp.br
authors.forename: F R L
authors.initials: FR
authors.lastname: Sato
authors.forename: L
authors.initials: L
authors.lastname: Asprino
authors.forename: P Y
authors.initials: PY
authors.lastname: Noritomi
authors.forename: J V L
authors.initials: JV
authors.lastname: da Silva
authors.forename: M
authors.initials: M
authors.lastname: de Moraes
mesh_terms: D000497:Alloys / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D003198:Computer Simulation; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000295:instrumentation; D008904:Miniaturization; D008953:Models, Anatomic; D008954:Models, Biological; D056948:Orthognathic Surgical Procedures / Q000295:instrumentation*; D059229:Osteotomy, Sagittal Split Ramus / Q000295:instrumentation*; D011140:Polyurethanes / Q000737:chemistry; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D011140:Polyurethanes; D014025:Titanium