Powder Bed Fusion 3D Printing in Precision Manufacturing for Biomedical Applications: A Comprehensive Review

Effect of Different Sandblasting Parameters on the Properties of Additively Manufactured and Machined Titanium Surfaces

BACKGROUND/AIM

In dentistry, the surfaces of titanium implants are often sandblasted and acid-etched in order to support successful osseointegration. The aim of this study was to investigate the impact of various sandblasting parameters on the surface roughness, contact angle and surface energy of additively manufactured (TiAl6V4) and machined commercially pure titanium (cpTi) surfaces.

MATERIALS AND METHODS

A total of 56 disc-shaped samples were produced using either laser powder bed fusion (TiAl6V4) or using precision cutting (cpTi). The samples were then sandblasted with different angles, distances, and pressures using an automated sandblasting machine. Afterwards, surface roughness and contact angle for water and diiodomethane were measured, and scanning electron microscopy images were taken.

RESULTS

The results showed that the initially rough TiAl6V4 samples became smoother after sandblasting, while the smooth cpTi surfaces became rougher. Sandblasting pressure had the most significant influence on surface roughness. The surface energy of sandblasted TiAl6V4 samples showed no significant change compared to the as-built state (26.6±1.3 to 26.3±1.8 mJ/m2). In contrast, cpTi samples showed a reduction in surface energy after sandblasting (32.3±1.6 to 26.8±1.2 mJ/m2). Scanning electron microscopy revealed irregular surfaces with grooves and ridges for both types of samples. The roughness of TiAl6V4 decreased at higher sandblasting pressures, whereas cpTi surfaces became rougher.

CONCLUSION

Surface roughness after sandblasting is strongly influenced by the initial surface, which differs in additively manufactured TiAl6V4 samples compared to machined cpTi surfaces.

Hybrid Biomechanical Design of Dental Implants: Integrating Solid and Gyroid Triply Periodic Minimal Surface Lattice Architectures for Optimized Stress Distribution

BACKGROUND

Dental implantology has evolved significantly since the introduction of additive manufacturing, which allows for the reproduction of natural bone's porous architecture to improve bone tissue compatibility and address stress distribution issues important to long-term implant success. Conventional solid dental implants frequently cause stress shielding, which compromises osseointegration and reduces durability.

AIM

The current research proposes to examine the biomechanical efficacy of fully and hybrid gyroid triply periodic minimum surface (TPMS) latticed implants across different cell sizes to optimize stress distribution and improve implant durability.

METHODS

This study evaluates six fully and hybrid gyroid (TPMS) latticed implants, including fully latticed designs with three cell sizes-FLI_111 (1 mm × 1 mm × 1 mm), FLI_222 (2 mm × 2 mm × 2 mm), and FLI_333 (3 mm × 3 mm × 3 mm)-and hybrid gyroid TPMS latticed implants with solid necks in corresponding sizes-HI_111, HI_222, and HI_333. To enhance initial stability, a square-threaded design was added into the bottom part of both fully and hybrid lattice implants. The designs also incorporate anti-rotational connections to enhance fixation, and they undergo a clinical viability comparison with contemporary implants. To improve lattice designs, finite element analysis (FEA) was utilized through nTopology (nTOP 4.17.3) to balance stiffness and flexibility. To examine mechanical performance under realistic conditions, a dynamic mastication loading simulation was conducted for 1.5 s across three cycles.

RESULTS

The findings reveal that hybrid implants, particularly HI_222, exhibited improved mechanical characteristics by reducing micromotions at the bone-implant interface, improving osteointegration, and attaining better stress distribution.

CONCLUSIONS

By addressing stress shielding and boosting implant performance, this work paves the way for personalized implant designs, developing dental technology, and improving clinical results.

Recent advances in 3D food printing: Therapeutic implications, opportunities, potential applications, and challenges in the food industry

3D food printing (3DFP) offers a transformative approach in the food industry, diverging from traditional manufacturing techniques. The integration of food science and nutrition with 3DFP is pioneering personalized, eco-friendly, and nutrient-rich food options, overcoming limitations of traditional manufacturing methods. For the past 10 years, we have been strongly focused on creating innovative, efficient, and functional food products while allowing customization of food based on preferences for nutrition, flavor, texture, mouthfeel, and appearance. Beyond customization, 3DFP demonstrates promise in addressing pressing global challenges including food security, famine, and malnutrition by facilitating the production of fortified, shelf-stable food products suitable for resource- constrained environments. This comprehensive review explores the intersection of 3DFP with food constituents, emphasizing its potential in enhancing customization, sustainability, food safety, and shelf-life extension. Additionally, it discusses the therapeutic potential of 3D printed foods for various diseases, including gastrointestinal disorders, cancer, diabetes, neurodegenerative disorders, and food allergies. Moreover, the review examines potential food applications of 3DFP, such as in space food, food packaging, dairy industry, fruit and vegetable processing, and cereal-based foods. The review also addresses key challenges associated with 3DFP and underscores the importance of four-dimensional food printing (4DFP).

Harnessing the Potential of Natural Composites in Biomedical 3D Printing

Natural composites are emerging as promising alternative materials for 3D printing in biomedical applications due to their biocompatibility, sustainability, and unique mechanical properties. The use of natural composites offers several advantages, including reduced environmental impact, enhanced biodegradability, and improved tissue compatibility. These materials can be processed into filaments or resins suitable for various 3D printing techniques, such as fused deposition modeling (FDM). Natural composites also exhibit inherent antibacterial properties, making them particularly suitable for applications in tissue engineering, drug delivery systems, and biomedical implants. This review explores the potential of utilizing natural composites in additive manufacturing for biomedical purposes, discussing the historical development of 3D printing techniques; the types of manufacturing methods; and the optimization of material compatibility, printability, and mechanical properties to fully realize the potential of using natural fibers in 3D printing for biomedical applications.

Machine Learning in 3D and 4D Printing of Polymer Composites: A Review

The emergence of 3D and 4D printing has transformed the field of polymer composites, facilitating the fabrication of complex structures. As these manufacturing techniques continue to progress, the integration of machine learning (ML) is widely utilized to enhance aspects of these processes. This includes optimizing material properties, refining process parameters, predicting performance outcomes, and enabling real-time monitoring. This paper aims to provide an overview of the recent applications of ML in the 3D and 4D printing of polymer composites. By highlighting the intersection of these technologies, this paper seeks to identify existing trends and challenges, and outline future directions.

Influence of Proteins and Building Direction on the Corrosion and Tribocorrosion of CoCrMo Fabricated by Laser Powder Bed Fusion

Cobalt-chromium-molybdenum (CoCrMo) alloys are common wear-exposed biomedical alloys and are manufactured in multiple ways, increasingly using additive manufacturing processes such as laser powder bed fusion (LPBF). Here, we investigate the effect of proteins and the manufacturing process (wrought vs LPBF) and building orientation (LPBF-XY and XZ) on the corrosion, metal release, tribocorrosion, and surface oxide composition by means of electrochemical, mechanical, microscopic, diffractive, and spectroscopic methods. The study was conducted at pH 7.3 in 5 g/L NaCl and 5 mM 2-(N-morpholino) ethanesulfonic acid (MES) buffer, which was found to be necessary to avoid metal phosphate and metal-protein aggregate precipitation. The effect of 10 g/L bovine serum albumin (BSA) and 2.5 g/L fibrinogen (Fbn) was studied. BSA and Fbn strongly enhanced the release of Co, Cr, and Mo and slightly enhanced the corrosion (still in the passive domain) for all CoCrMo alloys and most for LPBF-XZ, followed by LPBF-XY and the wrought CoCrMo. BSA and Fbn, most pronounced when combined, significantly decreased the coefficient of friction due to lubrication, the wear track width and severity of the wear mechanism, and the tribocorrosion for all alloys, with no clear effect of the manufacturing type. The wear track area was significantly more oxidized than the area outside of the wear track. In the reference solution without proteins, a strong Mo oxidation in the wear track surface oxide was indicative of a pH decrease and cell separation of the anodic and cathodic areas. This effect was absent in the presence of the proteins.