Modelling and Analysis of the Effect of Angular Velocity and Acceleration on Brain Strain Field in Traumatic Brain Injury

Traumatic brain injury (TBI) has long been known as one of the most anonymous reasons for death around the world. A presentation of a model of what happens in the process has been under study for many years; and yet it remains a question due to physiological, geometrical and computational complications. Although the facilities for soft tissue modeling have improved and the precise CT-imaging of human head has revealed novel details of brain, skull and the interface (the meninges), a comprehensive FEM model of TBI is still being studied. This study aims to present an optimized model of human head including the brain, skull, and the meninges after a comprehensive study of the previous models. The model is then used to investigate the effects of various sudden velocity-acceleration impulses on the strain field of the brain by using FE method. Next, the results are summed up and compared with an existing criterion on damage threshold in the brain during trauma. To reach this aim, a full geometrical model of a 30-year-old patient’s head has been generated from CT-scan and MR data. The model has been exposed to 20 angular velocity-acceleration pulses. Subsequently, the changes in the strain field have been compared with the results obtained in the previous studies yielding acceptable accordance with a major previous criterion. The results also show that certain criteria can be generated on the threshold of damage in the brain.

Soft and Hard Tissue Management in Implant Therapy—Part II: Prosthetic Concepts

The ongoing pursuit of aesthetic excellence in the field of implant therapy has incorporated prosthetic concepts in the early treatment-planning phase, as well as the previously discussed surgical concepts. The literature has addressed these prosthetic and laboratory approaches required to enhance and perfect the soft and hard tissue management (SHTM). After surgically providing an acceptable hard tissue architecture and adequate timing of loading of the implant, the prosthetic phase is responsible for the soft tissue modeling, through correctly planned and executed procedures, which induce a satisfactory soft tissue profile by considering the microvasculature, the abutment connection and positioning, and the implementation of an adequate provisional phase. The objectives are the modeling of the soft tissues through the use of a conforming periorestorative interface which will produce desired and stable results.