Für die Spannungsanalyse des menschlichen Unterkiefers wurde ein flexibles numerisches Simulationskonzept auf der Basis einer Finite Element-Modellierung entwickelt. Eines der Ziele ist es, nicht nur Frakturen bei bekannter Gewalteinwirkung voherzusagen sondern umgekehrt auch forensisch die Rekonstruktion eines traumatologischen Geschehens zu ermöglichen. Zunächst wurde die individuelle Geometrie anhand von 3D-CT-Daten rekonstruiert. Zur Verringerung des Simulationsaufwandes wurde vorerst die anisotrope Strukturmechanik des Knochens auf ein homogenes und isotropes Materialverhalten reduziert. Unter der Annahme der Von-Mises-Spannung als Schädigungsindikator konnte man bei Simulationen von Schlägen aus verschiedenen Richtungen auf den Unterkiefer eine gute Übereinstimmung mit traumatologischen Standardsituationen erzielen. Als weitere Validierung des Modells wurde ein durch ein Röntgenbild vorgegebener realer „Schadensfall“ mit einer dreifachen Unterkieferfraktur nachsimuliert und damit das Schadensereignis rekonstruiert. Sinnvolle vorgesehene Ergänzungen des bisher realisierten Konzeptes sind die Einbeziehung des Nervkanals, der Kiefergelenkfunktion, des Parodontalapparates und der individuellen elastischen Knocheneigenschaften.

For the stress analysis of the human mandible a flexible simulation concept basing on finite element-method has been developed. One of the main issues is the prediction of fractures as a consequence of known forces as well as the forensic reconstruction of the traumatologic situation. At first, the individual geometry was reconstructed by 3D-CT-Scans. To reduce the simulation efforts, for the time being the anisotropic structural mechanics of the jaw bone was neglected in favour of an homogeneous and isotropic material law. Assuming the Von-Mises-Stress as a failure indicator the results of the simulations were in good agreement with typical traumatologic situations. For further validation of the model, a real failure case, shown on a radiograph of a injured human mandible with three fractures, was simulated and, by this, the real incident was reconstructed. Reasonable planned extensions of the actual simulation concept have the regard on the nerve channel, the temporomandibular joint's function, the paradontal apparatus and the individual mechanical properties of the bone.

The article describes part of a research project aiming to develop a new modular software tool for the individual dynamic numerical simulation of the human mandible using the finite element method (FEM). Its planned use in the clinical setting makes it very important to validate the results of the simulations. Here, the function of the masticatory muscles is to be tested. On the basis of biomechanical data from the literature, standard movements, such as closing the mouth, forward movement, lateral movement or backward movement, were dynamically simulated. Apart from muscle activity, the movements of the mandible are defined by the temporomandibular joint. At present, translating the condylar dynamics to the simulation still poses problems. For this reason, therefore, simulations of the two extreme cases "fixed" and "force-free" condyles are compared. While in the case of fixed condyles, some of the movements could be reproduced either not at all or only weakly, in the case of force-free condyles, all standard movements were reproduced qualitatively, albeit without the guiding effect of the joint capsule or the articular disc.

The article describes part of a research project aiming to develop a new modular software tool for the individual dynamic numerical simulation of the human mandible using the finite element method (FEM). Its planned use in the clinical setting makes it very important to validate the results of the simulations. Here, the function of the masticatory muscles is to be tested. On the basis of biomechanical data from the literature, standard movements, such as closing the mouth, forward movement, lateral movement or backward movement, were dynamically simulated. Apart from muscle activity, the movements of the mandible are defined by the temporomandibular joint. At present, translating the condylar dynamics to the simulation still poses problems. For this reason, therefore, simulations of the two extreme cases "fixed" and "force-free" condyles are compared. While in the case of fixed condyles, some of the movements could be reproduced either not at all or only weakly, in the case of force-free condyles, all standard movements were reproduced qualitatively, albeit without the guiding effect of the joint capsule or the articular disc.

A new modular software concept for individual numerical simulation of the human mandible using the finite element method (FEM) is presented. The main task is an individual analysis of regional stress and stress-compatibility on the basis of computed tomographic data in individual patients. Simulation should, however, also be possible in parallel with biomechanical experiments, or for further research projects. For this purpose, rapid and uncomplicated generation of the FEM model, easy modification of input data, and short computation times are required. Practical use in the clinical setting makes appreciable additional demands on the individual software components.

A new modular software concept for individual numerical simulation of the human mandible using the finite element method (FEM) is presented. The main task is an individual analysis of regional stress and stress-compatibility on the basis of computed tomographic data in individual patients. Simulation should, however, also be possible in parallel with biomechanical experiments, or for further research projects. For this purpose, rapid and uncomplicated generation of the FEM model, easy modification of input data, and short computation times are required. Practical use in the clinical setting makes appreciable additional demands on the individual software components.

For diagnostics in head and neck area different imaging modalities are applied to the same patient to obtain the necessary diagnostic information. By this, morphological as well as functional characteristics of the pathological findings can be found. Hereby, each of these imaging procedures has its specific advantages and disadvantages. The combination of these different modalities allows to use the advantageous properties of each method, whereby the negative aspects can be minimized. This gives the surgeon the best view on pathological processes which involve mutliple tissue structures. We propose a certain formal treatment of the registration problem and discuss some aspects of the surface-and voxel-based similarity measures in a context of simulated annealing optimization process. Precise correlation of the multimodal head and neck area images together with its various presentation techniques provides a valuable tool for physicians.

This paper introduces a new method for a precise planning of autologous bone grafts in cranio-and maxillofacial surgery. Depending on the complexity of the skull form, there are different donor sites where the transplant can be harvested, i.e. pelvis or shoulder-bone. The preselection of the donor site depends on the needed form (morphological fit) and the bony mass. The three-dimensional CT studies give a geometrical description of the bone part to be resected and transplanted. As guidelines in this procedure optimal fit of the transplant as well as minimal lesion of the donor site have to be recommended. We use a surface similarity measure in order to select the optimal donor region for an individually designed transplant.