The aim of the study was to compare two types of mandible reconstructive operations with scapula and fibula free flaps: procedures with 3-D models from thermoplastic materials and conventional planning surgeries. 8 patients were treated due to an advanced oral cavity squamous cell carcinoma. In four patients with a mandibular defect, a physical 3-D model consisting of the reconstructed and unaffected sites was prepared for a reconstruction protocol. The 3-D models were designed based to high resolution CT scans. Assessment of comparative functionality (stability of junction, mobility, mastication ability) and cosmetics was examined in both groups, following a 8 weeks healing period with better results in group with 3D model. 3-D models for mandible and donor bones allow to obtain better functionality of restored mandible in comparison to the traditional method also significantly decreases time of the operation and allows to achieve the desired shape and esthetic effect within the 1/3 of the lower face.
The paper presents results of research conducted on a batch of additively manufactured individualized openwork wrist–hand orthoses made of thermoplastics and designed automatically based on 3D-scanned geometry of a given patient. The aim of the work was to establish an automated design process and find a reliable set of parameters for rapid and affordable manufacturing of usable orthoses on popular 3D printers, with little or no supervision of the process. The paper presents motivations, methodology of automated design, plan of manufacturing and testing, the obtained results in terms of process stability, fit and assessment by patient and strength of the obtained orthoses. Almost 100 manufacturing processes of ready-to-use orthosis parts were carried out in a controlled environment and their results were analyzed thoroughly. The results are promising, as most of the obtained products fulfil the strength criteria, although not all of them meet the economic criteria. As a result, a recommended set of process parameters was determined. These parameters were included in a prototype of the automated design and in a production system developed by the authors.
Effective medical and biomedical engineering education is an important problem. Traditional methods are difficult and costly. That is why Virtual Reality is often used for that purpose. Educational medical VR is a well-developed IT field, with many available hardware and software solutions. Current solutions are prepared without methodological approach. As a result, each VR system used for medical purposes is unique -there is no standardization, which leads to increased development time and costs. The paper presents an original methodology that can be used for building immersive virtual reality (VR) applications dedicated to training medical skills. The methodology is named "knowledgeoriented medical virtual reality" (KOMVR), as it uses basic knowledge-engineering tools during processes of planning, building and verification of interactive educational solutions. The paper shows successive stages of the methodology and the tools used for its execution. Effectiveness of the proposed methodology is illustrated with a simple example -a human body atlas. Major time reduction can be achieved while using the methodology -time reduction in the presented case was from 50 to 14 working days. The proposed innovative approach can increase effectiveness of preparation of educational VR solutions in medicine, but also in other branches of engineering.
Numerous experimental studies, including experiments performed by the authors, have shown that the part orientation during layer deposition has a very strong influence on final strength of a product manufactured by additive Fused Deposition Technology. The paper presents the results of tensile, bending and impact strength tests performed on samples of various orientations, made out of ABS material using FDM technology. The results of these tests allowed discovering a unique phenomenon -with the changing orientation, not only the values of strength indexes change, but macroscopic material behavior under load as well. The transition between a "yield point" and "brittle" material usually happens in a certain range of orientation values, named a critical orientation by the authors. The paper indicates supposed ranges of critical orientation for various types of loads.
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