title: Three-dimensional finite element analysis of the mandible and temporomandibular joint during vertical ramus elongation by distraction osteogenesis.
abstract: Distraction osteogenesis has been accepted as an alternative treatment modality for hypoplastic mandibles. Knowledge about the changes occurring in the temporomandibular joint region during mandibular distraction osteogenesis is, however, limited and controversial. Stress distribution in the temporomandibular joint region during unilateral vertical mandibular ramus distraction was studied using a finite element model. The finite element model was based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the temporomandibular joint and mandible was analyzed quantitatively at different intervals of the vertical mandibular ramus elongation. During the distraction phase, the condyles, articular disks, and glenoid fossa regions were loaded with a differentiated stress pattern. The affected right condyle, disk, and fossa were submitted to increasing loads with increasing elongation compared with the contralateral temporomandibular joint. Loading on the unaffected left side shifted posteriorly and slightly laterally, because the left condyle was the center of rotation. The loading of the temporomandibular joint regions was low during the active distraction phase, although local areas were subjected to elevated peak stresses.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Nørrebrogade 44, Bygn. 9D, 8000 Aarhus C, Denmark. tkofo@akh.aaa.dk
authors.forename: Thomas
authors.initials: T
authors.lastname: Kofod
authors.forename: Paolo M
authors.initials: PM
authors.lastname: Cattaneo
authors.forename: Michel
authors.initials: M
authors.lastname: Dalstra
authors.forename: Birte
authors.initials: B
authors.lastname: Melsen
mesh_terms: D001171:Arthritis, Juvenile / Q000601:surgery; D003198:Computer Simulation; D003799:Dental Stress Analysis / Q000379:methods*; D005146:Facial Asymmetry / Q000503:physiopathology / Q000601:surgery; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000503:physiopathology* / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D008844:Micrognathism / Q000601:surgery; D019857:Osteogenesis, Distraction; D013314:Stress, Mechanical; D013704:Temporomandibular Joint / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology / Q000601:surgery