A biomechanical evaluation of mandibular angle fracture plating techniques

Purpose: The purpose of this investigation was evaluate the biomechanical b ehavior of a vast array of fixation philosophies and techniques that addres s mandibular angle fractures. Materials and Methods: A total of 150 polyurethane synthetic mandible repli cas (Synbone, Laudquart, Switzerland,) were used in this investigation. Fiv e controls and 5 each of 14 different fixation philosophies and techniques were subjected to vertical loading at the incisal edge and then repeated fo r contralateral loading in the molar region by an Instron 1331 (Instron, Ca nton, MA) servohydraulic mechanical testing unit. The fixation philosophies and techniques evaluated were the lag screw technique, monocortical superi or border plating techniques with varying sizes of plates and screws, monoc ortical 2-plate techniques with varying forms of fixation, monocortical ten sion band systems with associated bicortical stabilization plates of variou s types, and various forms of reconstruction plates. Load/displacement data within a 0 to 200 N range were recorded, Yield load, yield displacement, a nd stiffness were determined. Mean and standard deviations were calculated, and statistically significant differences within and among categories were determined using an analysis of variance (P < .05). Second-order polynomia l best-fit curves were also created for each group to further evaluate and compare the mechanical behavior. Results: For incisal edge loading, statistically significant differences (P < .05) were found for stiffness between some of the monocortical superior border fixation techniques, as well as for yield displacement between sever al forms of monocortical 2-plate fixation techniques. No other differences were found within categories or among the groups that best represented thei r categories. For contralateral molar loading, statistically significant di fferences existed within and among categories. Conclusions: Under the conditions of this experiment, all systems met or ex ceeded currently identified postoperative functional requirements for incis al edge loading, but failed to meet them for contralateral molar loading. ( C) 2001 American Association of Oral and Maxillofacial Surgeons.