title: Evaluation of a new optical measuring system for experiments on fractured human mandibles: a biomechanical feasibility study in maxillofacial surgery.
abstract: OBJECTIVE
  Biomechanical loading on human mandibles was performed and a new optical measurement device was introduced for the quantification of interfragmentary movement in fractured mandibles stabilized with different osteosynthesis systems.
  
  
  METHODS
  Comparison tests were performed with monocortical non-locking double plates and bicortical single locking plate. For the experiments on a specialized test bench, 18 ex vivo fractured human cadaveric mandibles were tested. Interfragmentary motion was detected in all three spatial dimensions using the optical measurement device PONTOS®. The movement was investigated over increasing incisal force and one summarized parameter was investigated.
  
  
  RESULTS
  For the maximal tested load of 300 N m, the resultant interfragmentary movements in the two investigated groups were 2.96 ± 1.85° for the fixation with two conventional miniplates (six hole, profile 1.0 mm) and 4.53 ± 2.49° for single bicortically fixed locking plates (four hole, profile 1.5 mm). For both plate systems, we used the 2.0 mm screw system.
  
  
  CONCLUSIONS
  The test bench in combination with the new optical device PONTOS(®) can test the primary stability of osteosynthesis. We offer a solution to the problem of rate of twist of the mandible as well as typical rotational problem in recent measurements. Further, the method can be used for development of new osteosynthesis products.
  
  
  CONCLUSIONS
  Pseudoarthrosis formation is a common problem based on unsatisfying fixation of the fracture gap. The here presented combination of mechanical tests and numerical simulations can provide support for an improved treatment of fractured mandibles.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Universitätsklinikum Aachen, RWTH Aachen, Pauwelsstr. 30, 52074 Aachen, Germany. timm.steiner@gmx.de
authors.forename: T
authors.initials: T
authors.lastname: Steiner
authors.forename: S
authors.initials: S
authors.lastname: Raith
authors.forename: S
authors.initials: S
authors.lastname: Eichhorn
authors.forename: S
authors.initials: S
authors.lastname: Doebele
authors.forename: S
authors.initials: S
authors.lastname: Trainotti
authors.forename: S
authors.initials: S
authors.lastname: Müller
authors.forename: M
authors.initials: M
authors.lastname: Eder
authors.forename: L
authors.initials: L
authors.lastname: Kovacs
authors.forename: R
authors.initials: R
authors.lastname: Burgkart
authors.forename: K-D
authors.initials: KD
authors.lastname: Wolff
authors.forename: F
authors.initials: F
authors.lastname: Hölzle
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001732:Bite Force; D001860:Bone Plates; D002102:Cadaver; D005240:Feasibility Studies; D005260:Female; D057918:Fiducial Markers; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008337:Mandibular Fractures / Q000473:pathology / Q000601:surgery*; D009068:Movement; D055096:Optical Devices; D010780:Photogrammetry / Q000379:methods; D012399:Rotation; D013314:Stress, Mechanical