AbstractsBiology & Animal Science

The surgical management of subcondylar fractures of the human mandible is an area of ongoing controversy, especially with reference to the type, number and configuration of plates and screws used to reduce the fracture. The biomechanical behaviour of a series of plate and screw configurations utilised to surgically manage fractures of the human mandibular condylar neck, were investigated using sophisticated finite element models of a human mandible. The finite element models constructed were unique compared to previous work in that they were: 1) computationally large; 2) modelled the mandible and cranium as an articulated unit; 3) modelled the muscles of mastication in a three dimensional manner to allow simulated masticatory loads to be applied in an anatomically realistic manner; 4) used the actual STL files of plates and screws to accurately incorporate them into the model; and 5) modelled the bone as a heterogeneous rather than a homogeneous material. In total, eight configurations, consisting of six commercially available plates and two unique patient specific plates were analysed. The modelling predicted that the most favourable biomechanical behaviour of a treated fracture was achieved with a combination of two, 2.0mm 4 hole plates arranged in a parallel fashion. Acceptable performance was predicted for two, 2.0mm 4 hole plates placed angled to each other, and also for a 1.5mm ‘X’ plate. One of the patient specific plates was predicted to achieve an acceptably stable fracture reduction, whilst the other patient specific plate did not. This demonstrated the potential utility of using finite element analysis to examine patient specific implants prior to manufacture and use.