Electron Beam Melting Technology Research Articles

Hot isostatic pressing as an alternative thermo-mechanical treatment for metallic full-arch implant-supported frameworks obtained by additive and subtractive manufacturing technology: Vertical and horizontal fit, screw removal torque, and stress analysis.

To assess vertical and horizontal fit, screw removal torque, and stress analysis (considered biomechanical aspects) of full-arch implant frameworks manufactured in Ti-6Al-4V through milling, and additive manufacturing Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM), and the effect of the thermo-mechanical treatment Hot Isostatic Pressing (HIP) as a post-treatment after manufacturing. Maxillary full-arch implant frameworks were made by milling, DMLS, and EBM. The biomechanical assessments were screw removal torque, strain-gauge analyses, and vertical and horizontal marginal fits. The vertical fit was assessed by the single-screw test and with all screws tightened. All frameworks were submitted to a standardized HIP cycle (920°C, 1000bar pressure, 2h), and the tests were repeated (α = 0.05). At the initial time, milled frameworks presented higher screw removal torque values, and DMLS and EBM frameworks presented lower levels of strain. Using the single-screw test, milled and DMLS frameworks presented higher vertical fit values, and with all screws tightened and horizontally, higher fit values were found for milled frameworks, followed by DMLS and EBM. After HIP, milling and EBM frameworks presented higher screw removal torque values; the lowest strain values were found for EBM. Using the single-screw test, milled and DMLS frameworks presented higher vertical fit values, and with all screws tightened and horizontally no differences were found. DMLS and EBM full-arch frameworks presented adequate values of screw removal torque, strain, and marginal fit, although the worst values of marginal fit were found for EBM frameworks. The HIP cycle enhanced the screw removal torque of milled and EBM frameworks and reduced the strain values of milled frameworks. The HIP represents a reliable post-treatment for Ti-6Al-4V dental prostheses produced by milling and EBM technologies.

Machining of a functional hip prosthesis cone in TI-6AL-4V ELI titanium alloy produced by electron beam melting

Digital manufacturing using 3D models and innovative fabrication methods present challenges for functional areas of medical devices. The advantages arising from 3D manufacturing processes like electron beam melting (EBM) play a major role in producing medical devices as, for example, orthopaedic implants. However, surfaces with functional demands for surface roughness and dimensional accuracy require machining operations to achieve the necessary standards. This study aimed to manufacture a functional cone of the modular component of the hip prosthesis through turning and to assess if an EBM-obtained component could offer better machinability as compared to wrought titanium and ensure functionality. To achieve this, the variances in cutting forces and surface roughness of the resulting surface were analysed during the turning tests. The results show that the EBM test samples had higher roughness (Ra) values, yet it was possible to achieve Ra = 0.4 μm for f = 0.1 mm/rev. and approximately 20% lower resulting cutting forces, for example, for f = 0.1 mm/rev, 122N compared to 101N. Using the Kienzle-Victor model, the specific cutting force of titanium EBM was determined to be 1775 N/mm2. The impact of the shell geometry of the EBM test samples had no significant effect on the results. This allows for the exploration of its potential in component design, as it provides an economic advantage in manufacturing. In conclusion, the cutting forces and surface roughness showed similar or superior machinability compared to that of wrought titanium. The EBM technology enables the production of intricate forms and facilitates finishing operations in functional zones.

Effect of density grading on the mechanical behaviour of advanced functionally graded lattice structures

Lattice structures have found significant applications in the biomedical field due to their interesting combination of mechanical and biological properties. Among these, functionally graded structures sparked interest because of their potential of varying their mechanical properties throughout the volume, allowing the design of biomedical devices able to match the characteristics of a graded structure like human bone. The aim of this works is the study of the effect of the density grading on the mechanical response and the failure mechanisms of a novel functionally graded lattice structure, namely Triply Arranged Octagonal Rings (TAOR). The mechanical behaviour was compared with the same lattice structures having constant density ratio. Electron Beam Melting technology was used to manufacture titanium alloy specimens with global relative densities from 10% to 30%. Functionally graded structures were obtained by increasing the relative density along the specimen, by individually designing the lattice's layers. Scanning electron and a digital microscopy were used to evaluate the dimensional mismatch between actual and designed structures. Compressive tests were carried out to obtain the mechanical properties and to evaluate the collapse modes of the structures in relation to their average relative density and lattice grading. Open-source Digital Image Correlation algorithm was applied to evaluate the deformation behaviour of the structures and to calculate their elastic moduli. The results showed that uniform density structures provide higher mechanical properties than functionally graded ones. The Digital Image Correlation results showed the possibility of effectively designing the different layers of functionally graded structures selecting desired local mechanical properties to mimic the different characteristics of cortical and cancellous bone.

Compressive creep behavior of selective electron beam melted high Nb containing TiAl alloy

In this study, the compressive creep behavior of Ti–45Al–8Nb alloy fabricated by selective electron beam melting technology at 800 °C and 850 °C was investigated. This alloy is mainly composed of equiaxed γ grains, and minor α2 and B2 grains. Creep results show that compressive creep behavior of this alloy is dependent on temperature, which is manifested in the significant increase of creep strain and creep rate with the increase of temperature. Through a multi-step creep test, the stress exponent n (2.65 at 800 °C and 3.65 at 850 °C) and activation volume V* (36.49 b3 at 800 °C and 53.51 b3 at 850 °C) were measured. Combined with kinetic analysis based on n and V* and TEM observation, compressive creep deformation of this alloy at 800 °C and 850 °C is dominated by dislocation motion, including dislocation slip and climb. Additionally, mechanical twinning also plays an important role in creep deformation. Driven by dislocation pile-ups or mechanical twins, discontinuous dynamic recrystallization (DDRX) occurs during creep. The degree of DDRX at 850 °C is greater. Sufficient DDRX greatly softens the alloy and accelerates creep rate, resulting in no steady-state creep stage at 850 °C.

Osseointegrability of 3D-printed porous titanium alloy implant on tibial shaft bone defect in rabbit model.

Previous studies have demonstrated the ability of osseointegration of porous titanium implants in cancellous bone. Our study was designed to (i) investigate the ability of bone ingrowth into 3D-printed porous titanium alloy implant on the cortical bone of rabbits using CT-scan and histology, and (ii) to identify the consistency of the radiology information between clinical Cone Beam Computed Tomography (CBCT) and Micro Computed Tomography (μCT) in the evaluation of bone ingrowth. The porous titanium alloy implants were 3D-printed employing the Electron Beam Melting (EBM) technology with an intended pore size of 600 μm and porosity of approximately 50 percent. Each implant was inserted into tibial diaphysis in one rabbit and its pores were classified as contacting bone or non-contacting bone. Depending on the time of explantation, the rabbits were divided into two groups: group 1 consisting of 6 rabbits between 13 and 20 weeks and group 2 consisting of 6 rabbits between 26 and 32 weeks. Tissue ingrowth into the non-bone contacting pores were evaluated by CBCT and histology. μCT was used to further investigate the bone ingrowth into four implants (two from each group were randomly chosen). The CBCT detected the present of tissue with bone-like density in both bone-contacting pores and non-bone-contacting pores of all implants. The μCT analysis also supported this result. All the bone-like tissues were then histologically confirmed to be mature bone. The analysis of CBCT data to assess bone ingrowth in porous implants had the sensitivity, specificity, positive and negative predictive values of 85, 84, 93 and 70 percent, respectively, when considering μCT assessment as the gold standard. Fully porous titanium alloy implant has great potential to reconstruct diaphyseal bone defect due to its good ability of osseointegration. CBCT is a promising method for evaluation of bone ingrowth into porous implants.

Speed function effects on properties of Ti-5Al-5Mo-5 V-1Cr-1Fe alloy manufactured by electron beam melting

The speed function (SF) parameter, which is a unique combination of beam speed and beam current, is one of the most important parameters of the electron beam melting (PBF-EB) production process. It allows the same process conditions (size of the melt pool, process temperature, etc.) to be maintained for parts with different geometries and sizes. The aim of this research was to understand the effect of SF on the Ti-5Al-5Mo-5V-1Cr-1Fe alloy produced by electron beam melting technology. The results showed that increasing the SF from 86 to 116 resulted in a decrease in the average process temperature, a decrease in the length of the α phase plates, and change in the proportion of α and β phases from 53% (SF 86) to 50% (SF 116) of the β phases. Differences in microstructure (column diameters, thickness, and length of α-phase plates), phase composition, microhardness, porosity at the bottom, and top of the samples were observed on all samples. The mechanical property analysis did not show a significant effect of SF on elongation, but an increase in SF from 86 to 96 resulted in an increase in ultimate tensile strength (UTS) of approximately 7%, whilst an additional increase to 116 resulted in a decrease in UTS of approximately 8.5% compared to SF 96. From the results, it can be seen that the microstructural and mechanical properties of the material strongly depend on the SF. Based on it, SF 86 can be considered as the recommended value for the manufacture of Ti-55511 alloy parts.

Customized Cost-Effective Cranioplasty for Large Asymmetrical Defects

Cranioplasty or cranial reconstruction is always a challenging procedure even for experienced surgeons. In this study, two different design techniques for customized cranial prostheses are assessed for cranial reconstruction. Mirror reconstruction is one of the commonly used reconstruction techniques that fails when cranial defects cross the midline of symmetry. Hence, there is a need for a design technique for the reconstruction of cranial defects irrespective of their location on the symmetrical plane. The anatomical reconstruction technique demonstrates its applicability for a wide spectrum of complex skull defects irrespective of the defective position in the anatomical structure. The paper outlines a methodological procedure involving a multi-disciplinary approach involving physicians and engineers in the design and reconstruction of customized cranial implants for asymmetrical skull defects. The proposed methodology is based on five foundation pillars including the multi-disciplinary approach, implant design process, additive-manufactured implant, implant fitting analysis, and cost and time analysis for the customized implant. The patient’s computed tomography scan data are utilized to model a customized cranial implant, which is then fabricated using electron beam melting technology. The dimensional validation of the designed and fabricated titanium implant based on the anatomical approach results in a precision of 0.6345 mm, thus indicating a better fit than the standard mirroring method. The results of fitting accuracy also reveal that the manufactured implant’s average deviation is very close to the planned reconstruction area with an error less than 1 mm, suggesting that the customized titanium implant fits the skull model quite precisely. The cost and time analysis reports that the cost for producing a customized cranial implant using electron beam melting technology is around USD 217.5 and the time taken to build is approximately 14 h and 27 min, which is low when compared to other studies. The cost and time analysis also demonstrates that the proposed design would be less burdensome to patients when compared to standard practice. Therefore, the new anatomical design process can be used effectively and efficiently to treat a number of diverse cranial abnormalities with the enhanced cranial implant design.

Green electrochemical polishing of EBM Ti6Al4V samples with preliminary fatigue results

Additive manufacturing technologies have several well-known advantages; however, the surface quality of the printed parts is poor, compromising the corrosion and mechanical properties. Thus, surface finishing treatments are necessary. The most post-processing treatments proposed in the literature are mechanical or chemical. The formers are contact techniques and cannot be suitable for complex geometry, while the latter use strong and dangerous reagents. This paper is aimed to investigate the effect of the electropolishing treatment, a contactless technique, using an eco-friendly electrolytic solution in reducing the roughness and improving the fatigue properties of Ti6Al4V specimens produced by electron beam melting technology. Several parameters affecting the effectiveness of the electropolishing treatment have been investigated, as interelectrode distance, stirring rate and duration time. An optimal combination of them allowed a uniform surface treatment and a significant roughness reduction (64% of Sa reduction for cylindrical specimens). Under sinusoidal loading conditions with a maximum stress of 378 MPa and a stress ratio equal to R = 0.1, the mean fatigue life of electropolished dog-bone specimens was 250% longer than that of as-built specimens.

An Innovative Method to Analyse the Geometrical Accuracy of Ti6Al4V Octet-Truss Lattice Structures.

Metal lattice structures manufactured utilising additive techniques are attracting increasing attention thanks to the high structural efficiency they can offer. Although many studies exist on the characterisation of massive parts in Ti6Al4V processed by Electron Beam Melting (EBM), several investigations are necessary to characterise the Ti6Al4V lattice structures made by the EBM process. The objective of this paper is to develop a measurement method to assess the dimensional accuracy of Ti6Al4V octet truss lattice structures manufactured by EBM technology. Beam specimens with a 2 mm diameter and different growth orientations with respect to the build direction were analysed. The geometry differences between the designed and the manufactured beam specimens were highlighted. Two effects were identified: (i) The EBM-manufactured beams are generally thinner than the designed ones, and (ii) the shape of the section was found to be almost circular for the beam specimens oriented at 45° and 90°; on the contrary, the section of the horizontal beam (0°) cannot be considered circular.

Subsidence of a partially porous titanium lumbar cage produced by electron beam melting technology.

The lumbar intervertebral devices are widely used in the surgical treatment of lumbar diseases. The subsidence represents a serious clinical issue during the healing process, mainly when the interfaces between the implant and the vertebral bodies are not well designed. The aim of this study is the evaluation of subsidence risk for two different devices. The devices have the same shape, but one of them includes a filling micro lattice structure. The effect of the micro lattice structure on the subsidence behavior of the implant was evaluated by means of both experimental tests and finite element analyses. Compressive tests were carried out by using blocks made of grade 15 polyurethane, which simulate the vertebral bone. Non-linear, quasi-static finite element analyses were performed to simulate experimental and physiologic conditions. The experimental tests and the FE analyses showed that the subsidence risk is higher for the device without micro lattice structure, due to the smaller contact surface. Moreover, an overload in the central zone of the contact surface was detected in the same device and it could cause the implant failure. Thus, the micro lattice structure allows a homogenous pressure distribution at the implant-bone interface.

Industrial Applications of Lattice Structures in Components Made with EBM Additive Technology

AbstractThe aim of this study is to promote the industrial use of “lattice” structures in metal components made with Electron Beam Melting (EBM) technology.The degree of customization and the level of geometric complexity achieved with EBM technology in the production of metal components in the Aerospace and Racing sectors, favors the use of lighter and more performing designs characterized by reticular (or “lattice”) structures. Starting from the original massive design of the component and taking into account the geometric constraints and load conditions acting on the component, the search for the new design takes place in a software environment through the topological optimization process. At the end of the process, the optimized design is created by replacing the solid parts with a unit cell that is repeated periodically. From the comparison between the component with original layout, built using the standard Melt theme of EBM technology, and the equivalent component with optimized layout, created with the Net theme of the same technology, the advantage of using reticular structures to lighten the components and the possibility offered by EBM technology to practically implement these structures are highlighted.The search for lighter and more performing designs for metal components promotes the use of “lattice” structures, which can be created by exploiting the potential of Additive Manufacturing technologies.The possibility of creating very complex geometries makes EBM technology perfect for sectors where particular characteristics are required in the components produced, such as the Aerospace and the Racing sector. The existence of the Net theme also ensures that it is possible to print reticular structures with EBM technology, that allow to reduce the weight of the components and, at the same time, improve performance.

Additive Manufacturing of Metallic Frameworks Supported by the All-on-Six Implant Concept: Dimensional Precision After Veneer Layering and Spark Erosion.

To compare frameworks manufactured by selective laser melting (SLM) and electron beam melting (EBM) with frameworks manufactured by milling, regarding dimensional precision after veneer layering and spark erosion for the all-on-six implant concept. Frameworks (n = 5/group) were manufactured by milling, SLM, and EBM. Dimensional precision of the frameworks was evaluated by marginal fit, screw loosening torque, and strain. Marginal fit was assessed by the single screw protocol. The screw-loosening torque was measured for the evaluation of screw stability. Tension distribution was analyzed with strain gauges. All frameworks received veneer layering followed by the marginal fit, screw-loosening torque, and strain gauge tests. Subsequently, the frameworks were subjected to the spark erosion process. The analyses were repeated after each stage (baseline, veneer layering, and spark erosion). Data was explored by two-way repeated-measures analysis of variance (ANOVA) with the Bonferroni test (α = .05). At baseline, the highest (worst) marginal fit values were displayed by SLM frameworks (mean ± standard deviation [SD]: 186.13 ± 21.27 μm), while the milling group (83.30 ± 12.03 μm) showed the lowest (best) values (P < .05). After veneer layering, EBM presented the worst marginal fit values (222.55 ± 52.56 μm; P < .05) among the groups. Over time (from the baseline to veneer layering), the marginal fit values increased (became worse) for milling (P = .002) and EBM (P < .001), while for SLM (P = .002) the values decreased (improved). Compared with veneer layering data, spark erosion improved the marginal fit values only for EBM (P = .005). Irrespective of time, the screw-loosening torque for the milling group showed higher values. The lowest strain was found for the SLM at baseline (P < .05), but it increased after veneer layering (P = .015) and after spark erosion (P = .028). Additive technologies are promising for dental applications. In addition, all technologies demonstrated accuracy in the manufacturing of implant-supported frameworks, especially the EBM technology, which demonstrated biomechanical behavior similar to the milling technology after the intervals (baseline, veneer layering, and spark erosion) assessed in the study.

Three-Dimension-Printed Custom-Made Prosthetic Reconstructions in Bone Tumors: A Single Center Experience.

Bone can be affected by different neoplastic conditions. Limb salvage surgery has become the preferred treatment strategy for most malignant tumors of the extremities. Advanced 3D printing technology has transformed the conventional view of oncological surgery. These types of implants are produced by electron beam melting (EBM) technology by sintering titanium powder in a scaffold shape designed following a project designed from HRCT and MRI. The aim of our study was to evaluate the outcomes and the mid-term follow-up of a population treated with 3D-printed custom-made prosthesis implantation in major oncological bone resection or after failure of primary implants. The primary outcome was the general patient satisfaction one year after surgery. The secondary outcomes were: mortality rate, treatment related complication rate, functional and clinical outcomes (KPS, ADL and IADL). Eight patients were included, five females and two males, with a mean age of 50.3 (±23.72) years at the surgery. The enrolled patients reported a mean satisfaction rate after surgery of 7.38 (±2) where 10 was the maximum value. There were no changes between pre- and postoperative mean KPS (81.43 +/−10.69). Mean preoperative ADL and IADL score was in both cases 4.86 (±1.07), while postoperative was 5 (±0.82), with a delta of 0.13 (p > 0.05). Custom-made prosthesis permits reconstructing bone defects caused by large tumor resection, especially in anatomically complex areas, restoring articular function.

Implant-Abutment Discrepancy Before and After Acrylic Resin Veneering of Complete-Arch Titanium Frameworks Manufactured Using Milling and Electron Beam Melting Technologies.

To assess the implant-abutment discrepancy of complete-arch frameworks manufactured using milling and additive electron beam melting (EBM) technologies, before and after acrylic resin veneering application. A definitive implant cast with six implant replicas was digitized using a laboratory scanner. A software program was used to design an implant-supported framework which was manufactured using milling (M group) and EBM (EBM group) technologies (n = 10). In the M group, titanium milled specimens were fabricated. In the EBM group, titanium EBM specimens were obtained. A coordinate measurement machine (CMM) was used to assess the implant-abutment discrepancy at x-, y-, and z-axed between the specimens and the implant-abutment replicas of the definitive cast. The implant replicas positioned on the lateral incisor positions were not able to be assessed. The 3D gap discrepancy was calculated: . Acrylic resin veneering procedures were finished and the same CMM measurements were completed. Three-way analysis of variance (ANOVA) test was used to analyze the data (α = 0.05). The manufacturing method (df = 1, F = 7.00, p = 0.009) and implant position (df = 3, F = 129.82, p < 0.001) were significant predictors of the x-axis discrepancy. The veneering procedures (df = 1, F = 21.55, p < 0.001) and implant position (df = 3, F = 95.42, p < 0.001) were significant predictors of the y-axis discrepancy. The manufacturing method (df = 1, F = 11.79, p = 0.001) was a significant predictor of the z-axis discrepancy. Lastly, the manufacturing method (df = 1, F = 5.11, p = 0.026), implant position (df = 3, F = 11.36, p < 0.001), and veneering procedures (df = 1, F = 41.56, p < 0.001) were significant predictors of the 3D gap discrepancy in which the manufacturing method explains the 2.37% of variation in the 3D gap discrepancy, the implant position explains the 15.82% of variation in the 3D gap discrepancy, and veneering procedures explain the 19.29% of variation in the 3D gap discrepancy results. The manufacturing methods, veneering procedures, and implant position influenced the linear implant-abutment discrepancy. The milled technique tested obtained lower linear implant-abutment discrepancy compared with the EBM method evaluated. The acrylic resin veneering procedures increased the implant-abutment discrepancy.

Ti-6Al-4V Octet-Truss Lattice Structures under Bending Load Conditions: Numerical and Experimental Results

Metal lattice structures produced by means of additive techniques are attracting increasing attention thanks to the high structural efficiency they can offer. In order to achieve the maximum structural performance, numerical design techniques are used almost exclusively, thus based on CAE-FEM codes. Nevertheless, the current manufacturing facilities do not yet guarantee defect-free components, and, therefore, such imperfections need to be introduced in the numerical models too. The present work aims to describe a FE modelling technique for lattice structures based on the use of beam and shell elements, and therefore with a very reduced computational cost. The main structural parameters, such as weight and stiffness and strength, are used to drive the model calibration. Simple mathematical relationships, based on Experimental-CAD-FEM comparisons, are provided to estimate the error related to the numerical model in a simple and fast way. The validation was performed by three-point bending test on flat specimen with regular octet-truss microstructure both with and without external skin. The test articles were produced in Ti6Al4V and by means of the electron beam melting (EBM) technology. The results obtained are in excellent agreement with the experimental ones, indeed the maximum error is about 3%. All this indicates these methodologies as possible tools for evaluating the performance of such kinds of high-tech structures.

Improved quality and functional properties of Ti-6Al-4V ELI alloy for personalized orthopedic implants fabrication with EBM process

Understanding the manufacturing process parameters and their correlation with final product functional properties is needed to ensure performance in critical applications in the medical industry. This article presents the holistic procedure for verifying the quality of manufactured products, including the determination of basic material characteristics and strength parameters based on EBM (Electron Beam Melting) technology for the titanium alloy Ti-6Al-4V ELI. The aim of this study was to investigate the effects of the manufacturing and post-processing methods used, on the geometric accuracy, microstructure, mechanical and cytotoxic properties of additively manufactured parts, especially in the form of personalized jaw implants. The effect of Hot Isostatic Pressing (HIP) treatment on microstructure and properties is also taken into account. The EBM manufacturing process was developed and samples were built using three different orientations: 0° (horizontally), 45° (diagonally), and 90° (vertically). The novel results are systematically presented and discussed beginning from the selection of process parameters, sample manufacturing, wide microstructural characterization, determination of static mechanical properties as well as geometric accuracy, and quality control verification depending on the manufacturing process and the post-processing methods used. The conducted research allowed for the presentation of the entire process chain of the EBM manufactured medical implant made of high-purity titanium alloy (Ti-6Al-4V ELI), thus filling the scientific gaps related to the selective presentation and discussion of research results published in the literature on the subject.

Mechanical and morphological characterization of BCC - derived unit cells for biomedical devices

3D periodic cellular solids attract great attentions for applications in the biomedical field due to the combination of their mechanical and morphological properties.The mechanical behaviour of two classes of periodic cellular structures has been investigated: the first one is a strut-based structure; the second is a triply periodic minimal surfaces (TPMS) structure. Such structures derived from the body centered cubic (BCC) unit cell and were the G7 strut-based and the IWP sheet-based TPMS structure.The study was aimed at the mechanical and morphological characterization of the above cited cells for their application in biomedical devices. By means of the additive manufacturing Electron Beam Melting (EBM) technology, the G7 microlattice structures have been produced in titanium alloy. Compression tests have been carried out on three different levels of relative density, selected to evaluate the effect of this parameter on the mechanical properties.The correlation between relative density and mechanical properties of the G7 structure was defined by the Gibson-Ashby model. SEM analyses have been performed before the experimental tests in order to detect the morphological features and the matching between designed and real parameters, and after the tests to evaluate the failure mechanism of the structures. The experimental tests results were used for the validation of a non-linear finite element model of both G7 and IWP structures with the application of the Johnson-Cook plasticity model. Different cell configurations were obtained by varying the relative density and the cell diameter, in order to evaluate the cell size effect on the mechanical properties. G7 unit cell meets the mechanical and morphological requirements for the application in the biomechanical field. However, the analysis of the collapse mode showed that an improvement of the mechanical behaviour is required. The numerical analyses performed on the IWP unit cell allowed to assess that the structure is suitable for the production of biomedical devices.

The performance tests of three-dimensional printing titanium alloy craniomaxillofacial bone plate: A preliminary preclinical study

Background/purposeBecause of the complex anatomical structure of the maxillofacial skeleton, bending plates is necessary during surgery. The fast developing three-dimensional printing (3DP) technology has provided a new method for making personalized craniomaxillofacial bone plates. However, the properties of these bone plates remain unknown. This study evaluates the mechanical, fatigue, and morphological properties of these bone plates, which may provide data supporting future clinical applications. Materials and methodsThe 3DP bone plate was fabricated by selective laser melting (SLM) and electron beam melting (EBM) technologies. Mechanical, surface, and defect analyses were performed to compare their properties with a standard machined sample. One-way analysis of variance was applied, with p < 0.05 considered significant. ResultsThe 3DP craniomaxillofacial bone plate had better bending strength than that of the standard machined plate (p < 0.01). Whereas the fatigue resistance of the 3DP bone plate needs to be improved in the future. Surface analysis indicated greater roughness of the 3DP bone plate (p < 0.01). However, the surface roughness could be significantly reduced by polishing the surface, which would meet the needs of clinical application after polishing. Further defect analysis revealed the internal defect inside the plate, which should be avoided to improve the mechanical strength of the printed sample in the future. ConclusionThe 3DP titanium craniomaxillofacial bone plate has good mechanical performance and surface morphology, meeting the requirements of clinical application. However, poorer fatigue resistance and a high number of internal defects should be modified in the future.

Electrochemical deposition of ceramic-like coatings on Ti-6Al-4V parts fabricated by electron beam melting

The problems of micro-arc oxidation of titanium alloy parts Ti-6Al-4V produced by electron beam melting technology were considered. The phase composition, thickness and roughnessof the obtained coating have been evaluated.

Sustained Release of VEGF to Promote Angiogenesis and Osteointegration of Three-Dimensional Printed Biomimetic Titanium Alloy Implants.

Tumor resection and treatment of trauma-related regional large bone defects have major challenges in the field of orthopedics. Scaffolds that treat bone defects are the focus of bone tissue engineering. 3D printing porous titanium alloy scaffolds, prepared via electron beam melting technology, possess customized structure and strength. The addition of a growth factor coating to the scaffold introduces a specific form of biological activation. Vascular endothelial growth factor (VEGF) is key to angiogenesis and osteogenesis in vivo. We designed a porous titanium alloy scaffold/thermosensitive collagen hydrogel system, equipped with VEGF, to promote local osseointegration and angiogenesis. We also verified the VEGF release via thermosensitive collagen and proliferation and induction of the human umbilical vein endothelial cells (HUVECs) via the composite system in vitro. In vivo, using microscopic computed tomography (Micro-CT), histology, and immunohistochemistry analysis, we confirmed that the composite scaffold aids in angiogenesis-mediated bone regeneration, and promotes significantly more bone integration. We also discovered that the composite scaffold has excellent biocompatibility, provides bioactive VEGF for angiogenesis and osteointegration, and provides an important theoretical basis for the restoration of local blood supply and strengthening of bone integration.