Tissue Integration and Biological Cellular Response of SLM-Manufactured Titanium Scaffolds (original) (raw)
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An in vitro Study on the Biocompatibility of Titanium Implants Made by Selective Laser Melting
Biotechnology and Bioprocess Engineering, 2019
Customized medical implants obtained by selective laser melting have an important applicability due the accurate architecture which promotes the osteointegration, osteoconduction, and osteoinduction. This study assessed the in vitro effect of titanium scaffolds, both pure and covered with a layer of hydroxyapatite, on mesenchymal stem cells harvested from various oral tissues. Eight titanium implants were manufactured by selective laser melting, obtaining a porosity of 63.4% and a pore size of 600 µm. Four matrices were covered with nano-hydroxyapatite. Four lines of mesenchymal stem cells isolated from the apical papilla, the dental pulp, the inter-radicular bone, and the tuberosity bone were seeded on the implants. The cells' proliferation, viability, and differentiation into the osteoblastic lineage were assessed after 18 days, using light microscopy and fluorescence. Our results indicated that the titanium matrices did not exert cytotoxic effect. The cells seeded on titanium matrices conditioned with nanohydroxyapatite had a slightly higher proliferation rate. The stem cells isolated from the inter-radicular bone had the most intense proliferation and differentiation towards the osteoblastic lineage showing a nodular architecture. In conclusion, the oral mesenchymal stem cells have the potential to promote and improve bone regeneration when associated with the titanium scaffolds manufactured by selective laser melting, either non-coated or coated with hydroxyapatite. These findings open new perspectives for the bone reconstruction in the oral and maxillofacial surgery field.
Tissue Engineering Part A, 2013
The treatment of large bone defects still poses a major challenge in orthopaedic and cranio-maxillofacial surgery. One possible solution could be the development of personalized porous titanium-based implants designed to meet all mechanical needs with a minimum amount of titanium and maximum osteopromotive properties so that it could be combined with growth factor loaded hydrogels or cell constructs to realize advanced bone tissue engineering strategies. Such implants could prove useful for mandibular reconstruction, spinal fusion, the treatment of extended long bone defects, or to fill in gaps created upon autograft harvesting. The aim of this study was to determine the mechanical properties and potential of bone formation of light weight implants generated by Selective Laser Melting (SLM). We mainly focused on osteoconduction, since this is a key feature in bone healing and could serve as back-up for osteoinduction and cell transplantation strategies. To that end, defined implants were produced by SLM and their surfaces were either left untreated, sandblasted or sandblasted/acid etched. In vivo bone formation with the different implants was tested throughout calvarial defects in rabbits and compared to untreated defects. Analysis by µCT and histomorphometry revealed that all generatively produced porous Ti structures were well osseointegrated into the surrounding bone. The histomorphometric analysis revealed that bone formation was significantly increased in all implant treated groups compared to untreated defects and significantly increased in sand blasted implants compared to untreated ones.
Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery, 2015
The purpose of this study was to verify the modeling accuracy of various products, and to produce custom-made devices for bone augmentation in individual patients requiring implantation. Two-(2D) and three-dimensional (3D) specimens and custom-made devices that were designed as membranes for guided bone regeneration (GBR) were produced using a computer-aided design (CAD) and rapid prototyping (RP) method. The CAD design was produced using a 3D printing machine and selective laser melting (SLM) with pure titanium (Ti) powder. The modeling accuracy was evaluated with regard to: the dimensional accuracy of the 2D and 3D specimens; the accuracy of pore structure of the 2D specimens; the accuracy of porosity of the 3D specimens; and the error between CAD design and the scanned real product by overlapped images. The accuracy of the 2D and 3D specimens indicated precise results in various parameters, which were tolerant in ISO 2768-1. The error of overlapped images between the CAD and scan...
Materials science & engineering. C, Materials for biological applications, 2016
Selective laser melting (SLM) is an additive manufacturing technique with the ability to produce metallic scaffolds with accurately controlled pore size, porosity, and interconnectivity for orthopedic applications. However, the optimal pore structure of porous titanium manufactured by SLM remains unclear. In this study, we evaluated the effect of pore size with constant porosity on in vivo bone ingrowth in rabbits into porous titanium implants manufactured by SLM. Three porous titanium implants (with an intended porosity of 65% and pore sizes of 300, 600, and 900μm, designated the P300, P600, and P900 implants, respectively) were manufactured by SLM. A diamond lattice was adapted as the basic structure. Their porous structures were evaluated and verified using microfocus X-ray computed tomography. Their bone-implant fixation ability was evaluated by their implantation as porous-surfaced titanium plates into the cortical bone of the rabbit tibia. Bone ingrowth was evaluated by their ...
Tissue Engineering Part C: Methods, 2009
Selective laser melting (SLM), a method used in the nuclear, space, and racing industries, allows the creation of customized titanium alloy scaffolds with highly defined external shape and internal structure using rapid prototyping as supporting external structures within which bone tissue can grow. Human osteoblasts were cultured on SLM-produced Ti6Al4V mesh scaffolds to demonstrate biocompatibility using scanning electron microscopy (SEM), fluorescence microscopy after cell vitality staining, and common biocompatibility tests (lactate dihydrogenase (LDH), 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), 5-bromo-2deoxyuridine (BrdU), and water soluble tetrazolium (WST)). Cell occlusion of pores of different widths (0.45-1.2 mm) was evaluated. Scaffolds were tested for resistance to compressive force. SEM investigations showed osteoblasts with well-spread morphology and multiple contact points. Cell vitality staining and biocompatibility tests confirmed osteoblast vitality and proliferation on the scaffolds. Pore overgrowth increased during 6 weeks' culture at pore widths of 0.45 and 0.5 mm, and in the course of 3 weeks for pore widths of 0.55, 0.6, and 0.7 mm. No pore occlusion was observed on pores of width 0.9-1.2 mm. Porosity and maximum compressive load at failure increased and decreased with increasing pore width, respectively. In summary, the scaffolds are biocompatible, and pore width influences pore overgrowth, resistance to compressive force, and porosity.
Journal of Materials Science: Materials in Medicine, 2019
The aim of this study was to assess the osseointegration of two series of titanium (Ti) scaffolds with 0.8 and 1 mm cell size obtained by Selective Laser Melting (SLM) technique. One of the series had the Ti surface unmodified, while the other had the Ti surface coated with silicon-substituted nano-hydroxyapatite (nano-HapSi). The scaffolds were implanted in the femur bone defects of 6 White Californian male rabbits: three animals were implanted with 0.8 mm cell size scaffolds and three animals with 1 mm cell size scaffolds, respectively. The bone fragments and scaffolds harvested at 2, 4 and 6 months were histologically analyzed using conventional light microscopy (LM) and scanning electron microscopy (SEM) for the qualitative evaluation of the bone tissue formed in contact with the scaffold. Both LM and SEM images indicated a better osseointegration for nano-HapSi coated Ti scaffolds. LM revealed that the compact bone formed in the proximity of nano-HapSi-coated scaffolds was better organized than spongy bone associated with unmodified scaffolds. Moreover, Ti scaffolds with meshes of 0.8 mm showed higher osseointegration compared with 1 mm. SEM images at 6 months revealed that the bone developed not only in contact with the scaffolds, but also proliferated inside the meshes. Nano-HapSi-coated Ti implants with 0.8 mm meshes were completely covered and filled with new bone. Ti scaffolds osseointegration depended on the mesh size and the surface properties. Due to the biocompatibility and favorable osseointegration in bone defects, nano-HapSi-coated Ti scaffolds could be useful for anatomical reconstructions.
Biomimetic Porous Titanium Scaffolds for Orthopedic and Dental Applications
The development of artificial organs and implants for replacement of injured and diseased hard tissues such as bones, teeth and joints is highly desired in orthopedic surgery. Orthopedic prostheses have shown an enormous success in restoring the function and offering high quality of life to millions of individuals each year. Therefore, it is pertinent for an engineer to set out new approaches to restore the normal function of impaired hard tissues. Over the last few decades, a large number of metals and applied materials have been developed with significant improvement in various properties in a wide range of medical applications. However, the traditional metallic bone implants are dense and often suffer from the problems of adverse reaction, biomechanical mismatch and lack of adequate space for new bone tissue to grow into the implant. Scientific advancements have been made to fabricate porous scaffolds that mimic the architecture and mechanical properties of natural bone. The porous structure provides necessary framework for the bone cells to grow into the pores and integrate with host tissue, known as osteointegration. The appropriate mechanical properties, in particular, the low elastic modulus mimicking that of bone may minimize or eliminate the stress-shielding problem. Another important approach is to develop biocompatible and corrosion resistant metallic materials to diminish or avoid adverse body reaction. Although numerous types of materials can be involved in this fast developing field, some of them are more widely used in medical applications. Amongst them, titanium and some of its alloys provide many advantages such as excellent biocompatibility, high strength-to-weight ratio, lower elastic modulus, and superior corrosion resistance, required for dental and orthopedic implants. Alloying elements, i.e. Zr, Nb, Ta, Sn, Mo and Si, would lead to superior improvement in properties of titanium for biomedical applications. New processes have recently been developed to synthesize biomimetic porous titanium scaffolds for bone replacement through powder metallurgy. In particular, the space holder sintering method is capable of adjusting the pore shape, the porosity, and the pore size distribution, notably within the range of 200 to 500 µm as required for osteoconductive applications. The present chapter provides a review on the characteristics of porous metal scaffolds used as bone replacement as well as fabrication processes of porous titanium (Ti)
Biomimetic Porous Titanium Scaffolds for Orthopaedic and Dental Applications
2010
The development of artificial organs and implants for replacement of injured and diseased hard tissues such as bones, teeth and joints is highly desired in orthopedic surgery. Orthopedic prostheses have shown an enormous success in restoring the function and offering high quality of life to millions of individuals each year. Therefore, it is pertinent for an engineer to set out new approaches to restore the normal function of impaired hard tissues. Over the last few decades, a large number of metals and applied materials have been developed with significant improvement in various properties in a wide range of medical applications. However, the traditional metallic bone implants are dense and often suffer from the problems of adverse reaction, biomechanical mismatch and lack of adequate space for new bone tissue to grow into the implant. Scientific advancements have been made to fabricate porous scaffolds that mimic the architecture and mechanical properties of natural bone. The porous structure provides necessary framework for the bone cells to grow into the pores and integrate with host tissue, known as osteointegration. The appropriate mechanical properties, in particular, the low elastic modulus mimicking that of bone may minimize or eliminate the stress-shielding problem. Another important approach is to develop biocompatible and corrosion resistant metallic materials to diminish or avoid adverse body reaction. Although numerous types of materials can be involved in this fast developing field, some of them are more widely used in medical applications. Amongst them, titanium and some of its alloys provide many advantages such as excellent biocompatibility, high strength-to-weight ratio, lower elastic modulus, and superior corrosion resistance, required for dental and orthopedic implants. Alloying elements, i.e. Zr, Nb, Ta, Sn, Mo and Si, would lead to superior improvement in properties of titanium for biomedical applications. New processes have recently been developed to synthesize biomimetic porous titanium scaffolds for bone replacement through powder metallurgy. In particular, the space holder sintering method is capable of adjusting the pore shape, the porosity, and the pore size distribution, notably within the range of 200 to 500 µm as required for osteoconductive applications. The present chapter provides a review on the characteristics of porous metal scaffolds used as bone replacement as well as fabrication processes of porous titanium (Ti)
Properties of biocomposites based on titanium scaffolds with a different porosity
Bulletin of Materials Science
Open-porous titanium scaffolds have been widely investigated for orthopaedic and dental applications because of their ability to form composites via bone ingrowth into pores and promote implant fixation with mother bone. In this work, porous titanium scaffolds coated with a diamond-like carbon were produced, and their ability to form biocomposites was evaluated through in vivo experiments. Three types of the open-porous scaffolds made of spongy titanium granules (porosity 0.3, 0.4 and 0.5, Young's modulus 4.4, 3.5 and 0.6 GPa) were implanted into a bone defect of sheep. Time dependences of the Young's modulus of titanium scaffold-bone tissue biocomposites were determined through the measurement of Young's modulus of the extracted scaffolds after 4, 8, 24 and 52 weeks of surgery. The Young's modulus of biocomposite is dependent not only on the time of composite formation but also on the porosity of scaffold.
Journal of the Mechanical Behavior of Biomedical Materials, 2019
Lattice structure based morphologically matched scaffolds is rapidly growing facilitated by developments in Additive Manufacturing. These porous structures are particularly promising due to their potential in reducing stress shielding and maladapted stress concentration. Accordingly, this study presents Extra Low Interstitial (ELI) Titanium alloy based morphological scaffolds featuring three different porous architecture. All scaffolds were additively manufactured using Selective Laser Melting from Ti-6Al-4V ELI with porosities of 73.85, 60.53 and 55.26% with the global geometry dictated through X-Ray Computed Tomography. The elastic and plastic performance of both the scaffold prototypes and the bone section being replaced were evaluated through uniaxial compression testing. Comparing the data, the suitability of the Maxwell criterion in evaluating the stiffness behaviour of fully porous morphological scaffolds are carried out. The outcomes show that the best performing scaffolds presented in this study have high strength (169 MPa) and low stiffness (5.09 GPa) suitable to minimise stress shielding. The matching morphology in addition to high porosity allow adequate space for flow circulation and has the potential to reduce maladapted stress concentration. Finally, the Electron Diffraction X-ray analysis revealed a small difference in the composition of aluminium between the particle and the bonding material at the scaffold surface.