Biomechanical comparison of four mandibular angle fracture fixation techniques

Novel Design of Interlocking 3-Dimensional Miniplate in Mandibular Angle Fractures: An In Vitro Study

The evolution of osteosynthesis has led to the development of novel miniplate designs, including 3-dimensional (3D) miniplates, which offer improved biomechanical stability. However, mandible fractures resulting from the high impact have a complex fracture configuration. Hence, the authors developed interlocking 3D miniplate to overcome the difficulty in miniplate and screw placement to avoid critical anatomic structures, that is, dental roots and nerve, while still providing stability for the fracture fragments. The interlocking 3D miniplates can be formed according to the specific needs by adjusting the horizontal and vertical cross struts configuration. This study describes a design process of interlocking 3D miniplates and evaluates biomechanical performance compared to standard miniplates. Finite element analysis was performed to evaluate the design's stress state using human and goat mandible models under various loading conditions. After the authors, established that our design was feasible for fabrication, the authors developed the prototype for biomechanical testing. Biomechanical testing was conducted on 10 goat mandibles to compare stability and displacement under various load between the interlocking 3D miniplate and the standard miniplate configuration. Biomechanical testing revealed reduced displacement in all directions with the interlocking 3D miniplate compared to the standard miniplate. Furthermore, there was a significant difference in all loads in the buccal-lingual displacement ( P <0.05). The novel interlocking 3D miniplate design shows an adequate ability to provide stability for fixation for mandibular fractures, as evidenced by finite element analysis and biomechanical testing. Further research is necessary to validate these findings and explore the clinical application of interlocking 3D miniplates in mandibular fracture management.

Integrity of a Single Superior Border Plate Repair in Mandibular Angle Fracture: A Novel Cadaveric Human Mandible Model

PURPOSE

The purpose of this study was to compare the integrity of human mandibular angle fracture after fixation with a single titanium plate along the upper lateral border with that of the native human mandible.

MATERIALS AND METHODS

This cross-sectional anatomic study involved the left hemimandibles of 16 human cadavers. They were selected and divided in 2 groups by remaining dental status. Additional predictor variables, such as height of the left mandibular body and gender, were noted. Left hemisected native mandibles were mounted at the condyle and loaded on an Instron 5565 mechanical unit (Instron Corp, Norwood, MA) until fracture. Fractured left hemimandibles were fixated with a titanium miniplate and screws. After plate fixation, each hemimandible was reloaded on an Instron 5565 until fracture. Data pertaining to primary outcomes of load application were recorded in newtons at displacement values of 3.0, 5.0, and 7.0 mm and at displacement at fixation failure. Primary outcomes of maximum load and displacement at maximum load were recorded in newtons and millimeters, respectively. Descriptive statistics were used to summarize sample characteristics. Statistical comparisons were performed using t test, χ² (or Fisher exact) test, and linear regression. Pearson correlation was used to examine relations between select biomechanical measurements.

RESULTS

The study sample was composed of 12 female and 4 male cadaveric hemimandibles. Donors' age at time of death ranged from 54 to 95 years (mean age, 78.94 yr). The mean maximum load in native and plated hemimandibles was 943.56 and 292.57 N, respectively (P < .0001).

CONCLUSION

Key clinical findings of this study include the inability of single plate mandible fixation to restore the mandible to preinjury levels and verification that gender, dental status, and height of the mandible do not alter the stability of a single plate fixated mandible.