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Biomechanical Evaluation of Fixation Techniques for Bridging Segmental Mandibular Defects
Jonathan M. Doty, MD;
David Pienkowski, PhD;
Michele Goltz, BS;
Richard H. Haug, DDS;
Joseph Valentino, MD;
Oneida A. Arosarena, MD
Arch Otolaryngol Head Neck Surg. 2004;130:1388-1392.
Objective To compare biomechanical properties of currently available plating systems used to reconstruct segmental mandibular defects.
Design Controlled in vitro investigation.
Setting Academic medical center laboratory.
Interventions 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.
Author Affiliations: Division of Otolaryngology–Head and Neck Surgery (Drs Doty, Valentino, and Arosarena) and Center for Biomechanical Engineering, Division of Orthopedic Surgery (Dr Pienkowski), Department of Surgery, University of Kentucky Medical Center; Center on Drug and Alcohol Research, University of Kentucky College of Research and Graduate Studies (Ms Goltz); and Division of Oral and Maxillofacial Surgery, University of Kentucky College of Dentistry (Dr Haug), Lexington.
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