scholarly journals MECHANICAL TESTING AND NUMERICAL MODELLING OF POROUS STRUCTURES IMPROVING OSEINTEGRATION OF IMPLANTS

2020 ◽  
Vol 26 ◽  
pp. 126-132
Author(s):  
Petr Vakrčka ◽  
Aleš Jíra ◽  
Petra Hájková
Keyword(s):  
Additive Manufacturing ◽  
Numerical Modelling ◽  
Mechanical Testing ◽  
Bone Ingrowth ◽  
Porous Structures ◽  
Advantages And Disadvantages ◽  
Controlled Porosity ◽  
3D Printed ◽  
Titanium Alloy Ti6al4v ◽  
Wall System

Implants, such as dental, are ordinary devices in medical care nowadays, even though they are quite expensive. In the present study, the use of trabecular and gyroid structures as external layer of implants is examined. The advantage of porous structures compared to surface modification of compact implants is the possibility to be fabricated by additive manufacturing together with the whole implant. The additive manufacturing also allows us to produce various shapes with controlled porosity for bone ingrowth. The design of 6 types of trabecular and 4 types of gyroid structures is part of the study. The trabecular structures are strut-based, whereas the gyroid structures are based on a wall system. The study is focused on mechanical testing of samples which were 3D printed from the titanium alloy Ti6Al4V. The gyroid structures, which we evaluated as more reliable, were chosen for numerical modelling. Other observed advantages and disadvantages of the structures are also discussed.

scholarly journals Post-Processing of 3D-Printed Polymers

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 61
Author(s):  
John Ryan C. Dizon ◽  
Ciara Catherine L. Gache ◽  
Honelly Mae S. Cascolan ◽  
Lina T. Cancino ◽  
Rigoberto C. Advincula
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
3D Models ◽  
Industrial Applications ◽  
Post Processing ◽  
Processing Methods ◽  
Stl File ◽  
Advantages And Disadvantages ◽  
Manufacturing Operations ◽  
3D Printed

Additive manufacturing, commonly known as 3D printing, is an advancement over traditional formative manufacturing methods. It can increase efficiency in manufacturing operations highlighting advantages such as rapid prototyping, reduction of waste, reduction of manufacturing time and cost, and increased flexibility in a production setting. The additive manufacturing (AM) process consists of five steps: (1) preparation of 3D models for printing (designing the part/object), (2) conversion to STL file, (3) slicing and setting of 3D printing parameters, (4) actual printing, and (5) finishing/post-processing methods. Very often, the 3D printed part is sufficient by itself without further post-printing processing. However, many applications still require some forms of post-processing, especially those for industrial applications. This review focuses on the importance of different finishing/post-processing methods for 3D-printed polymers. Different 3D printing technologies and materials are considered in presenting the authors’ perspective. The advantages and disadvantages of using these methods are also discussed together with the cost and time in doing the post-processing activities. Lastly, this review also includes discussions on the enhancement of properties such as electrical, mechanical, and chemical, and other characteristics such as geometrical precision, durability, surface properties, and aesthetic value with post-printing processing. Future perspectives is also provided towards the end of this review.

scholarly journals Analysis of the Porous Structures from Laser Powder Bed Fusion Additive Manufacturing

2021 ◽  
Author(s):  
Chang Jiang Wang ◽  
Kevin Hazlehurst ◽  
Arun Arjunan ◽  
Lida Shen
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Bone Ingrowth ◽  
Manufacturing Processes ◽  
Powder Bed Fusion ◽  
Porous Structures ◽  
Laser Powder Bed Fusion ◽  
Stress Concentrations ◽  
Powder Bed ◽  
Internal Surfaces

Open and closed porous structures with lattice and honeycomb geometry can be built using laser powder bed fusion additive manufacturing processes. The porous structures can be used to tailor the mechanical properties of a component or provide other functionality, such as for bone ingrowth in medical implants. Porous structures were created and analysed in this paper both physically and using finite element modelling. It was found that the accuracy of the built parts was reasonable and within the manufacturing processes general tolerance of +/- 50 μm. However, it was noticeable that the corners of the square shape pores were naturally filleted by the manufacturing process. The finite element model was developed using ANSYS software, stress concentrations were observed in the porous structures under loading. In addition to this, fragments of the material were present on the internal surfaces of the pores, which were formed from partially melted powder particles.

3D Printing of Dual-cell Delivery Titanium Alloy Scaffolds for Improving Osseointegration Through Enhancing Angiogenesis and Osteogenesis

2021 ◽  
Author(s):  
Heng Zhao ◽  
Shi Shen ◽  
Lu Zhao ◽  
Yulin Xu ◽  
Yang Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Bone Ingrowth ◽  
Hypoxia Inducible Factor ◽  
Three Dimensional ◽  
Bone Defects ◽  
Transcriptional Level ◽  
Metal Implants ◽  
Marrow Mesenchymal Stem Cells ◽  
3D Printed ◽  
Titanium Alloy Ti6al4v

Abstract BACKGROUND: The repair of large bone defects is a great challenge for orthopedics. Although the development of three-dimensional (3D) printed metal implants with optimized the pore structure have effectively promoted the osseointegration. However, due to the biological inertia of titanium alloy (Ti6Al4V) surface and the neglect of angiogenesis, some patients still suffer from postoperative complications such as dislocation or loosening of the prosthesis. METHODS: The purpose of this study was to construct 3D printed porous Ti6Al4V scaffolds filled with bone marrow mesenchymal stem cells (BMSC) and endothelial progenitor cells (EPC) loaded hydrogel and evaluate the effects of this composite implants on angiogenesis and osteogenesis, thus promoting osseointegration. RESULTS: The porosity and pore size of prepared 3D printed porous Ti6Al4V scaffolds were 69.2 ± 0.9 % and 593.4±16.9 μm, respectively, which parameters were beneficial to blood vessel formation and bone ingrowth. The BMSC and EPC filled into the scaffold pores after being encapsulated by hydrogels can maintain high viability. As a cells containing composite implant, BMSC and EPC loaded hydrogel incorporated into 3D printed porous Ti6Al4V scaffolds enhancing angiogenesis and osteogenesis to repair bone defects efficiently. At the transcriptional level, the composite implant up-regulated the expression levels of the osteogenesis-related genes alkaline phosphatase (ALP) and osteocalcin (OCN), and angiogenesis-related genes hypoxia-inducible factor 1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF). CONCLUSION: Overall, the strategy of loading porous Ti6Al4V scaffolds to incorporate cells is a promising treatment for improving osseointegration.

scholarly journals 3D printing of dual-cell delivery titanium alloy scaffolds for improving osseointegration through enhancing angiogenesis and osteogenesis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Heng Zhao ◽  
Shi Shen ◽  
Lu Zhao ◽  
Yulin Xu ◽  
Yang Li ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Bone Ingrowth ◽  
Hypoxia Inducible Factor ◽  
Three Dimensional ◽  
Bone Defects ◽  
Transcriptional Level ◽  
Marrow Mesenchymal Stem Cells ◽  
A Cell ◽  
3D Printed ◽  
Titanium Alloy Ti6al4v

Abstract Background The repair of large bone defects is a great challenge for orthopedics. Although the development of three-dimensional (3D) printed titanium alloy (Ti6Al4V) implants with optimized the pore structure have effectively promoted the osseointegration. However, due to the biological inertia of Ti6Al4Vsurface and the neglect of angiogenesis, some patients still suffer from postoperative complications such as dislocation or loosening of the prosthesis. Methods The purpose of this study was to construct 3D printed porous Ti6Al4V scaffolds filled with bone marrow mesenchymal stem cells (BMSC) and endothelial progenitor cells (EPC) loaded hydrogel and evaluate the efficacy of this composite implants on osteogenesis and angiogenesis, thus promoting osseointegration. Results The porosity and pore size of prepared 3D printed porous Ti6Al4V scaffolds were 69.2 ± 0.9 % and 593.4 ± 16.9 μm, respectively, which parameters were beneficial to bone ingrowth and blood vessel formation. The BMSC and EPC filled into the pores of the scaffolds after being encapsulated by hydrogels can maintain high viability. As a cell containing composite implant, BMSC and EPC loaded hydrogel incorporated into 3D printed porous Ti6Al4V scaffolds enhancing osteogenesis and angiogenesis to repair bone defects efficiently. At the transcriptional level, the composite implant up-regulated the expression levels of the osteogenesis-related genes alkaline phosphatase (ALP) and osteocalcin (OCN), and angiogenesis-related genes hypoxia-inducible factor 1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF). Conclusions Overall, the strategy of loading porous Ti6Al4V scaffolds to incorporate cells is a promising treatment for improving osseointegration.

AM-Serienproduktion für die Automobilindustrie/AM series production for the automotive industry

2020 ◽  
Vol 110 (11-12) ◽  
pp. 752-757
Author(s):  
Lukas Weiser ◽  
Marco Batschkowski ◽  
Niclas Eschner ◽  
Benjamin Häfner ◽  
Ingo Neubauer ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Automotive Industry ◽  
Series Production ◽  
Production Scale ◽  
Additive Fertigung ◽  
Small Series ◽  
Start Up ◽  
3D Printed ◽  
Component Quality

Die additive Fertigung schafft neue Gestaltungsfreiheiten. Im Rahmen des Prototypenbaus und der Kleinserienproduktion kann das Verfahren des selektiven Laserschmelzens genutzt werden. Die Verwendung in der Serienproduktion ist bisher aufgrund unzureichender Bauteilqualität, langen Anlaufzeiten sowie mangelnder Automatisierung nicht im wirtschaftlichen Rahmen möglich. Das Projekt „ReAddi“ möchte eine erste prototypische Serienfertigung entwickeln, mit der additiv gefertigte Bauteile für die Automobilindustrie wirtschaftlich produziert werden können. Additive manufacturing (AM) offers new freedom of design. The selective laser-powderbed fusion (L-PBF) process can be used for prototyping and small series production. So far, it has not been economical to use it on a production scale due to insufficient component quality, long start-up times and a lack of automation. The project ReAddi aims to develop a first prototype series production to cost-effectively manufacture 3D-printed components for the automotive industry.

scholarly journals Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 724
Author(s):  
Amilton Iatecola ◽  
Guilherme Arthur Longhitano ◽  
Luiz Henrique Martinez Antunes ◽  
André Luiz Jardini ◽  
Emilio de Castro Miguel ◽  
...  
Keyword(s):  
Surface Modification ◽  
Additive Manufacturing ◽  
Bone Ingrowth ◽  
Orthopedic Implants ◽  
Coated Sample ◽  
High Mechanical Strength ◽  
Coated Surface ◽  
Surface Modification Techniques ◽  
Almost All ◽  
Cobalt Base

Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Liang Wu ◽  
Stephen Beirne ◽  
Joan-Marc Cabot Canyelles ◽  
Brett Paull ◽  
Gordon G. Wallace ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Polylactic Acid ◽  
Fused Filament Fabrication ◽  
Flexible Approach ◽  
Electroosmotic Pump ◽  
3D Printed ◽  
Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

scholarly journals 3D Printed Masks for Powders and Viruses Safety Protection Using Food Grade Polymers: Empirical Tests

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 617
Author(s):  
Ruben Foresti ◽  
Benedetta Ghezzi ◽  
Matteo Vettori ◽  
Lorenzo Bergonzi ◽  
Silvia Attolino ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Material Selection ◽  
Mechanical Resistance ◽  
Biological Safety ◽  
Fused Deposition ◽  
Industrial Grade ◽  
Safety Protection ◽  
3D Printed ◽  
Manufacturing Technologies

The production of 3D printed safety protection devices (SPD) requires particular attention to the material selection and to the evaluation of mechanical resistance, biological safety and surface roughness related to the accumulation of bacteria and viruses. We explored the possibility to adopt additive manufacturing technologies for the production of respirator masks, responding to the sudden demand of SPDs caused by the emergency scenario of the pandemic spread of SARS-COV-2. In this study, we developed different prototypes of masks, exclusively applying basic additive manufacturing technologies like fused deposition modeling (FDM) and droplet-based precision extrusion deposition (db-PED) to common food packaging materials. We analyzed the resulting mechanical characteristics, biological safety (cell adhesion and viability), surface roughness and resistance to dissolution, before and after the cleaning and disinfection phases. We showed that masks 3D printed with home-grade printing equipment have similar performances compared to the industrial-grade ones, and furthermore we obtained a perfect face fit by customizing their shape. Finally, we developed novel approaches to the additive manufacturing post-processing phases essential to assure human safety in the production of 3D printed custom medical devices.

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