title: Failure location prediction by finite element analysis for an additive manufactured mandible implant.
abstract: In order to reconstruct a patient with a bone defect in the mandible, a porous scaffold attached to a plate, both in a titanium alloy, was designed and manufactured using additive manufacturing. Regrettably, the implant fractured in vivo several months after surgery. The aim of this study was to investigate the failure of the implant and show a way of predicting the mechanical properties of the implant before surgery. All computed tomography data of the patient were preprocessed to remove metallic artefacts with metal deletion technique before mandible geometry reconstruction. The three-dimensional geometry of the patient's mandible was also reconstructed, and the implant was fixed to the bone model with screws in Mimics medical imaging software. A finite element model was established from the assembly of the mandible and the implant to study stresses developed during mastication. The stress distribution in the load-bearing plate was computed, and the location of main stress concentration in the plate was determined. Comparison between the fracture region and the location of the stress concentration shows that finite element analysis could serve as a tool for optimizing the design of mandible implants.
authors.affiliation: Division of Applied Mechanics, Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Huo
authors.affiliation: Department of Oral and Maxillofacial Surgery, Skåne University Hospital, SE-221 85 Lund, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Dérand
authors.affiliation: Sports Tech Research Centre, Department of Quality Technology and Management, Mechanical Engineering and Mathematics, Mid Sweden University, SE-831 25 Östersund, Sweden.
authors.forename: Lars-Erik
authors.initials: LE
authors.lastname: Rännar
authors.affiliation: Department of Surgical Sciences, Oral & Maxillofacial Surgery, Uppsala University, 751 85 Uppsala, Sweden.
authors.forename: Jan-Michaél
authors.initials: JM
authors.lastname: Hirsch
authors.affiliation: Division of Applied Mechanics, Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden. Electronic address: kristofer.gamstedt@angstrom.uu.se.
authors.forename: E Kristofer
authors.initials: EK
authors.lastname: Gamstedt
mesh_terms: D000368:Aged; D000497:Alloys; D016477:Artifacts; D001732:Bite Force; D018786:Bone Substitutes; D003198:Computer Simulation; D019544:Equipment Failure Analysis / Q000379:methods*; D005240:Feasibility Studies; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008339:Mandibular Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008409:Mastication / Q000502:physiology; D008410:Masticatory Muscles / Q000503:physiopathology; D008954:Models, Biological; D016062:Porosity; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D054457:Tissue Scaffolds; D014025:Titanium; D014057:Tomography, X-Ray Computed
chemical_list: D000497:Alloys; D018786:Bone Substitutes; D014025:Titanium
keywords: Computed tomography; Failure; Finite element simulations; Homogenisation; Mandible implant