title: Strength analysis of Le Fort I osteotomy fixation: titanium versus resorbable plates.
abstract: OBJECTIVE
  The purpose of this study was to compare the biomechanical characteristics of metallic and polymeric fixation systems using a 3-dimensional skull model to simulate clinical conditions of maxillary advancement and loading.
  
  
  METHODS
  Standard titanium, prebent titanium, and resorbable plates and mesh were applied to surgically altered polyurethane skulls. The constructs were loaded using an Instron machine (Instron Inc, Canton, MA) in anterior-posterior (AP) and inferior-superior (IS) directions. The load displacement, load to failure, and deformation magnitudes and modes of failure were recorded. Statistical studies included analysis of variance (ANOVA) at P <.05.
  
  
  RESULTS
  Elastic stiffness was different among groups in the AP direction, but no significant difference was found in the IS direction. The IS loading direction load displacement (stiffness) was significantly greater than that on AP loading. The maximum load for permanent deformation was larger in the AP direction, while the maximum load for breaking was larger in the IS direction.
  
  
  CONCLUSIONS
  The overall evaluation of the model and test analyses supported the relative value of this in vitro system and study procedure. All systems showed load capacity magnitudes above 285 N (64 lbs) and more elastic resistance in the IS direction. The resorbable systems showed lower elastic stiffness compared with the titanium systems, but they appear to be adequate for fixation and withstanding the forces of mastication.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Alabama at Birmingham Medical Center, Birmingham, AL, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Araujo
authors.forename: P D
authors.initials: PD
authors.lastname: Waite
authors.forename: J E
authors.initials: JE
authors.lastname: Lemons
mesh_terms: D020341:Absorbable Implants; D000704:Analysis of Variance; D001672:Biocompatible Materials; D001860:Bone Plates; D003799:Dental Stress Analysis; D004548:Elasticity; D019544:Equipment Failure Analysis; D006801:Humans; D019248:Jaw Fixation Techniques / Q000295:instrumentation*; D019344:Lactic Acid; D008422:Materials Testing; D008953:Models, Anatomic; D019340:Osteotomy, Le Fort; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D014025:Titanium
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D014025:Titanium