Biomechanical Evaluation of the Cadaver Mandible Under Cyclic Compressive Loads

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AIM:This study evaluated biomechanical behavior of human cadaveric mandibles in terms of fatigue life, failure modes, maximum load to failure, and stiffness variation under cyclic compressive loading. METHODS: Twelve fresh-frozen mandibles were harvested from donated human cadavers, and grouped two ways to undergo different cyclic compressive loading configurations simulating biting cycles. Fracture locations, maximum load to failure and number of loading cycles to failure were noted, and stiffness variation was determined. Mann-Whitney test and Pearson’s correlation test were used for statistical data analyses. RESULTS: The mandibles in molar loading group exhibited fracture at mandibular angle as the prominent failure mode whereas those in incisor loading group predominantly failed in condylar region. Stiffness reduction in the mandibles of both groups showed a steep initial decline followed by a transition into constant stiffness. The distribution of age, maximum load to failure, cycles to failure, and overall change in stiffness were not significantly different (P>0.05 for α=0.05). Age had negative correlation with maximum load to failure (r=-0.51), cycles to failure (r=-0.01), overall change in stiffness (r=-0.12). Age and sex did not have significant effect on fatigue life and overall change in stiffness (P>0.05 for α=0.05). CONCLUSIONS: Stiffness in cadaver mandibles during cyclic fatigue loading showed a steep decrease which transitioned into a region of saturation with nearly no change. The study indicates that the older cadaver mandibles tend to fail at lower magnitudes of cyclic compressive load.