From Linear to Viscoelastic Model of Mandible: A Paradigm Shift in FEM Study

The clinical effectiveness and stress exerted by orthodontic appliances to the bone needs to be analysed because the loading force produces strain in the soft tissue matrix which is responsible for bone remodelling. Finite element analysis stimulates complex biologic structures and their bio-mechanical behaviours under different conditions and various forces in orthodontics for many decades. Using finite element analysis many researchers attempted to show stress and strain distribution in maxilla, the mandible generated by orthodontic appliances such as expanders, Class II correctors, face-masks and temporary anchorage devices. Despite all advancement , the clinical effects of the appliances where studied on a linear set of elastic material properties to stimulate behaviours of viscoelastic bone tissue. With elastic models, it is impossible to calculate displacements of the bone over a period of time, but it is crucial for when the study of orthodontic appliance like fixed functional appliance is carried out. While a viscoelastic model expresses changes over time. In this study, we aimed to compare the structural behaviours of a viscoelastic model of the mandible with forsus appliance in action with those of linear elastic model of mandible.