title: Biomechanical evaluation of fixation techniques for bridging segmental mandibular defects.
abstract: OBJECTIVE
  To compare biomechanical properties of currently available plating systems used to reconstruct segmental mandibular defects.
  
  
  METHODS
  Controlled in vitro investigation.
  
  
  METHODS
  Academic medical center laboratory.
  
  
  METHODS
  Thirty-two polyurethane mandibles were equally divided among 4 groups: mandibles with a 4-cm lateral segmental defect that was bridged with a (1) 3.0-mm locking-screw reconstruction plate, (2) 2.4-mm low-profile reconstruction plate, or (3) 2.4-mm reconstruction plate and (4) uncut (control) mandibles. All plates were contoured and secured to the synthetic mandibles with 4 bicortical screws on either side of the defect. Three constructs from each group were subjected to contralateral-molar single-load-to-failure testing. Mean yield displacement, yield load, and bending stiffness were quantified and compared among the 4 groups. The single-load-to-failure data were used to establish conditions for fatigue testing; such testing was then performed on the remaining 5 samples in each group. Mean cycles to failure were measured and compared among the 4 groups.
  
  
  RESULTS
  Mean yield displacement, yield load, and bending stiffness were comparable among the plated groups. Both the 3.0-mm locking-screw and 2.4-mm low-profile reconstruction plate designs withstood 1580 and 1124 times more cycles to failure, respectively (P = .005), than did the control group. The other reconstruction plate was also superior to the unplated controls, offering an 865-fold improvement.
  
  
  CONCLUSIONS
  All 3 mandibular fixation device systems tested produce comparable levels of single load to failure biomechanical integrity; however, the higher-profile plating system design offered slightly superior fatigue performance. No differences in performance were observed between the locking and nonlocking designs; neither failed at the screw-substrate interface.
authors.affiliation: Division of Otolaryngology-Head and Neck Surgery, University of Kentucky Medical Center, Lexington, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Doty
authors.forename: David
authors.initials: D
authors.lastname: Pienkowski
authors.forename: Michele
authors.initials: M
authors.lastname: Goltz
authors.forename: Richard H
authors.initials: RH
authors.lastname: Haug
authors.forename: Joseph
authors.initials: J
authors.lastname: Valentino
authors.forename: Oneida A
authors.initials: OA
authors.lastname: Arosarena
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008334:Mandible / Q000601:surgery*; D008341:Mandibular Prosthesis; D011140:Polyurethanes; D011474:Prosthesis Design
chemical_list: D011140:Polyurethanes