Mesh management methods in finite element simulations of orthodontic tooth movement

In finite element simulations of orthodontic tooth movement, one of the challenges is to represent long term tooth movement. Large deformation of the periodontal ligament and large tooth displacement due to bone remodelling lead to large distortions of the finite element mesh when a Lagrangian formalism is used. We propose in this work to use an Arbitrary Lagrangian Eulerian (ALE) formalism to delay remeshing operations. A large tooth displacement is obtained including effect of remodelling without the need of remeshing steps but keeping a good-quality mesh. Very large deformations in soft tissues such as the periodontal ligament is obtained using a combination of the ALE formalism used continuously and a remeshing algorithm used when needed. This work demonstrates that the ALE formalism is a very efficient way to delay remeshing operations

The biology of orthodontic tooth movement: a mathematical model

peer reviewe

Mechanisms of cell migration in the adult brain: modelling subventricular neurogenesis.

Neurogenesis has been the subject of active research in recent years. Although the majority of neurons form during the embryonic period, neurogenesis continues in restricted regions of the mammalian brain well into adulthood. In rodent brains, neuronal migration is present in the rostral migratory stream (RMS), connecting the subventricular zone to the olfactory bulb (OB). The migration in the RMS is characterised by a lack of dispersion of neuroblasts into the surrounding tissues and a highly directed motion towards the OB. This study uses a simple mathematical model to investigate several theories of migration of neuroblasts through the RMS proposed in the literature, including chemo-attraction, chemorepulsion, general inhibition and the presence of a migration-inducing protein. Apart from the general inhibition model, all the models were able to provide results in good qualitative correspondence with the experimental observations

Feasibility of a novel system to prestress externally bonded reinforcement

The strengthening of concrete structures with externally bonded prestressed reinforcement has advantages compared to a passive system. The load bearing capacity is increased as well as the flexural stiffness. Prestressing allows to exploit the high tensile strength of the fibres of the external reinforcement. A number of systems are already commercially available, however their use is restricted as they are more expensive and show some practical inconveniences in use. In this paper, a novel system is presented and a feasibility study is carried out. The novel system aims to overcome the inconveniences of existing prestressing systems. The system has a reduced number of necessary operations and keeps a small distance between the concrete surface and the laminate. In the initial study presented, feasibility tests are carried out on simplified test systems and the design of the anchorage to the concrete and of the clamping system are discussed. © 2011 RILEM.status: publishe