ИСТИНА

Can finite element analysis be used to infer habitual mandibular loading and so diet? Finite element analysis (FEA) is increasingly used to relate skeletal form to function. Here we present preliminary investigations that form part of a study to assess the extent to which human mandibular form and function reflects diet; comparing ancient hunter gatherers with agriculturalists. The first step is to consider what the results of FEA analyses of mandibles mean; do they really reflect physiological function, and if not what do they tell us, if anything? We investigate two methodologically important points for FEA of a human mandible: the impact of different methods of constraining it, and the effects of different material properties of teeth, periodontal ligament and cancellous bone. A clinical CT scan is used to build FE models of the mandible with cortical bone, teeth, periodontal ligament and cancellous bone segmented. FEA is carried out using five different constraints and models with varying stiffness of the teeth, cancellous bone and periodontal ligament Each of the models is then used to simulate biting at each of three teeth: the central incisor, 1st premolar and 2nd molar. How the mandible is constrained has a large effect on the mode and magnitude of mandibular deformation while changing Young’s modulus of teeth, cancellous bone and periodontal ligament to that of cortical bone impacts significantly, but to a lesser degree. Without detailed and specific validation data there is no certainty that FEA replicates physiological functioning. As such, FEA of the mandible is best applied to questions that do not rely on accurate prediction of physiology.