Bone tissue engineering provided the innovative solution to regenerate bone tissue using scaffolds (porous) structures. This research investigates optimization, additive manufacturing methods and the application areas of triply periodic minimal surface-based (TPMS) porous structures in the broad field of tissue engineering through literature review. The properties of TPMS structures are compared with more classical strut-based structures. Also, information on how TPMS can be formulated and how they can be designed to obtain desired properties are presented. Attention is dedicated to the topological optimization process and how it can be applied to scaffolds to further increase their biomechanical properties and improve their design through density, heterogenization, and unit cell size grading. Common numerical algorithms as well as the difference between gradient-based and non-gradient-based algorithms are proposed. Efforts also include the description of the main additive manufacturing technologies that can be utilized to manufacture either stochastic or periodic scaffolds. The information present in this work should be able to introduce the reader to the use of TPMS structures in tissue engineering.

This literature review provides an in-depth exploration of the research conducted on residual stresses (RS) in Wire Arc Additive Manufacturing (WAAM) products, particularly focusing on how process parameters influence the phenomenon. The motivation of the study is the growing focus on WAAM technology and the observation that RS plays a crucial role in determining the mechanical behavior and structural integrity of WAAM components. Thus, the review is intended to provide a better understanding of the relationship between process parameters and RS to optimize the WAAM process and ensure the durability of the final products. It also summarizes key findings, measurement techniques, challenges, and future directions in this evolving field. The review also analyzes measurement techniques used to characterize RS in products fabricated by WAAM as a function of process parameters. Experimental measuring techniques and numerical analysis of RS to determine the impacts of RS in mechanical responses in products of WAAM were discussed. Experimental measuring techniques, such as X-ray diffraction, neutron diffraction (ND), contour and ND, digital image correlation, thermomechanical coupling and contour, and hole-drilling methods, along with numerical simulations like finite element analysis, are discussed to determine the impacts of RS on the mechanical responses of WAAM products. Additionally, it addresses the influence of thermal cycles, cooling rates, and deposition strategies on RS formation. The role of material properties, such as thermal conductivity and expansion coefficients, in RS development is also considered. By offering a comprehensive overview of current research trends and insights, this review serves as a valuable resource to guide future investigations, fostering the advancement of WAAM as a robust and efficient manufacturing technology. The review also underscores the importance of interdisciplinary approaches combining experimental and numerical methods to tackle the complex issues of RS in WAAM, aiming to enhance the performance and reliability of additively manufactured components.

The dimensional accuracy of additively manufactured (3D printed) medical models can be affected by various parameters. Although different methods are used to evaluate the accuracy of additively manufactured models, this study focused on the investigation of the dimensional accuracy of the medical model based the combination of reverse engineering (RE) and additive manufacturing (AM) technologies. Human femur bone was constructed from CT images and manufactured, using Fortus 450mc Industrial material extrusion 3D Printer. The additive manufactured femur bone was subsequently 3D scanned using three distinct non-contact 3D scanners. MeshLab was used for mesh analysis, while VX Elements was used for post-processing of the point cloud. A combination of the VX Inspect environment and MeshLab was used to evaluate the scanning performance. The deviation of the 3D scanned 3D models from the reference mesh was determined using relative metrics and absolute measurements. The scanners reported deviations ranging from −0.375 mm to 0.388 mm, resulting in a total range of approximately 0.763 mm with average root mean square (RMS) deviation of 0.22 mm. The results indicate that the additively manufactured model, as measured by 3D scanning, has a mean deviation with an average range of approximately 0.46 mm and an average mean value of around 0.16 mm.

Reverse engineering, a process of extracting information or knowledge from existing objects or systems, has gained significant attention in various fields, including medicine. This article presents a comprehensive literature review and a proof of concept on the application of reverse engineering in the medical field. The review particularly focuses on the reverse engineering process, available technologies, and their specific relevance to the medical domain. Various imaging techniques, such as computed tomography and magnetic resonance imaging, are discussed in respect of their integration with reverse engineering methodologies. Furthermore, the article explores the wide range of medical applications facilitated by reverse engineering, including prosthetics, implants, tissue engineering, and surgical planning. The potential of reverse engineering to enhance personalized medicine and patient-specific treatments is highlighted. A detailed proof of concept focusing on femur reconstruction is a significant component of the article. The proof of concept showcases the practical implementation of reverse engineering techniques to assist in designing and manufacturing precise custom-made implants and bone reconstruction. It emphasizes the integration of patient-specific anatomical data obtained through imaging technologies and the subsequent utilization of reverse engineering processes for anatomical reconstruction (solid modeling). Overall, this article provides an extensive overview of reverse engineering in medical applications, incorporating a literature review and a case study. The findings highlight reverse engineering’s potential to advance medical practices, improve patient outcomes, and foster personalized treatments. The review emphasizes the reverse engineering process, available technologies, and their specific relevance to the medical field, as well as their potential and effectiveness in advancing medical practices.

This study investigates the mechanical and biological properties of biomimetic Triply Periodic Minimal Surface (TPMS) based scaffolds Gyroid, Split P, and Neovius fabricated using the stereolithography process of additive manufacturing technique and biocompatible material for bone tissue engineering applications. Scaffolds were printed in both uniform and graded configurations at a fixed 60 % relative density and dimensions of 20 mm in diameter × 2 mm thickness. Compression test, energy absorption capacity and cell proliferation and attachment of the TPMS, were tested and analysed. The test results revealed that graded structures, particularly Split P and Neovius, demonstrated superior compressive strength, specific energy absorption, and elasticity compared to their uniform counterparts, indicating their suitability for load-bearing applications. Optical and Scanning Electron Microscopy analyses confirmed the consistency and accuracy of the 3D printed material distribution and structural performance. Biological evaluation using the A549 cell line demonstrated statistically significant differences in cell viability (p < 0.001) across scaffold types over 24, 48, and 72 h. Because A549 is a non-osteogenic screening model, these findings should be interpreted as preliminary cytocompatibility and attachment outcomes rather than osteogenic performance. This geometry-focused, material-agnostic study uses a dimensionally accurate SLA resin to isolate the effects of uniform vs. graded TPMS architectures on mechanics and early cell compatibility, establishing a controlled baseline to inform future work with bone-relevant cells and bioactive ceramics/metals. The Gyroid scaffold supported the highest early-stage proliferation, attributed to its continuous and highly interconnected pore geometry. These results emphasize the importance of geometry and grading in achieving a balance between mechanical integrity and biological compatibility. The potential of graded TPMS scaffolds to meet the complex demands of bone regeneration, providing a customizable platform for the development of next-generation orthopedic implants is suggested.