Indirect Additive Manufacturing Processing of Poly-Lactide-co-Glycolide

2015 ◽  
Vol 754-755 ◽  
pp. 985-989
Author(s):  
Shah Fenner Khan ◽  
M.J. German ◽  
K.W. Dalgarno
Keyword(s):  
Additive Manufacturing ◽  
Constant Pressure ◽  
Research Work ◽  
Mechanical Tests ◽  
Patient Specific ◽  
Manufacturing Method ◽  
Post Surgery ◽  
Fixation Plate ◽  
New Treatments ◽  
Specific Fracture

The research and development of biomaterials have brought about new treatments in regenerative medicine. The research work presented in this paper focus on the use of Poly-Lactide-co-glycolide (PLGA) in the fabrication of patient specific fracture fixation plate by indirect additive manufacturing method. The use of biopolymers such as PLGA has been seen as a solution to the problems of stress shield and post-surgery inherent in biometal fixation plates. This paper discusses the consequence of this processing method on characteristics and properties of the PLGA. PLGA of ratio 50:50, 65:35 and 85:15 was processed and compared. The granules of PLGA were positioned in the cavity of the stereolithography (SLA) mould and heated under constant pressure with sintering temperature of 73°C for 2.0hours. Both the variation in samples fabricated from this process with the designed model and the changes in material characteristics are below 10%. The flexural strength for PLGA of ratio 50:50, 65:35 and 85:15 is 73.8±2.3MPa, 75.0±2.8, 60.0±11.7, respectively. The characteristics and mechanical tests indicate that the results were comparable with conventional processing of PLGA.

scholarly journals Biofunctional Glycol-Modified Polyethylene Terephthalate and Thermoplastic Polyurethane Implants by Extrusion-Based Additive Manufacturing for Medical 3D Maxillofacial Defect Reconstruction

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1751
Author(s):  
Matthias Katschnig ◽  
Juergen Wallner ◽  
Thomas Janics ◽  
Christoph Burgstaller ◽  
Wolfgang Zemann ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Material Selection ◽  
Ex Vivo ◽  
Thermoplastic Polyurethane ◽  
Patient Specific ◽  
Ex Vivo Model ◽  
Manufacturing Method ◽  
Material Extrusion ◽  
Defect Reconstruction ◽  
Standard Implant

This work addresses the topic of extrusion-based additive manufacturing (filament-based material extrusion) of patient-specific biofunctional maxillofacial implants. The technical approach was chosen to overcome the shortcomings of medically established fabrication processes such as a limited availability of materials or long manufacturing times. The goal of the work was a successful fabrication of basic implants for defect reconstruction. The underlying vision is the implants’ clinic-internal and operation-accompanying application. Following a literature search, a material selection was conducted. Digitally prepared three-dimensional (3D) models dealing with two representative mandible bone defects were printed based on the material selection. An ex-vivo model of the implant environment evaluated dimensional and fitting traits of the implants. Glycol-modified PET (PETG) and thermoplastic polyurethane (TPU) were finally selected. These plastics had high cell acceptance, good mechanical properties, and optimal printability. The subsequent fabrication process yielded two different implant strategies: the standard implant made of PETG with a build-up rate of approximately 10 g/h, and the biofunctional performance implant with a TPU shell and a PETG core with a build-up rate of approximately 4 g/h. The standard implant is meant to be intraoperatively applied, as the print time is below three hours even for larger skull defects. Standard implants proved to be well fitting, mechanically stable and cleanly printed. In addition, the hybrid implant showed particularly cell-friendly behavior due to the chemical constitution of the TPU shell and great impact stability because of the crack-absorbing TPU/PETG combination. This biofunctional constellation could be used in specific reconstructive patient cases and is suitable for pre-operative manufacturing based on radiological image scans of the defect. In summary, filament-based material extrusion has been identified as a suitable manufacturing method for personalized implants in the maxillofacial area. A further clinical and mechanical study is recommended.

scholarly journals Size Effects in Finite Element Modelling of 3D Printed Bone Scaffolds Using Hydroxyapatite PEOT/PBT Composites

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1746
Author(s):  
Iñigo Calderon-Uriszar-Aldaca ◽  
Sergio Perez ◽  
Ravi Sinha ◽  
Maria Camara-Torres ◽  
Sara Villanueva ◽  
...  
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Tissue Regeneration ◽  
Finite Element Modelling ◽  
Bulk Material ◽  
Bone Tissue Regeneration ◽  
Patient Specific ◽  
Design Factor ◽  
Element Modelling ◽  
Uncertainty Sources

Additive manufacturing (AM) of scaffolds enables the fabrication of customized patient-specific implants for tissue regeneration. Scaffold customization does not involve only the macroscale shape of the final implant, but also their microscopic pore geometry and material properties, which are dependent on optimizable topology. A good match between the experimental data of AM scaffolds and the models is obtained when there is just a few millimetres at least in one direction. Here, we describe a methodology to perform finite element modelling on AM scaffolds for bone tissue regeneration with clinically relevant dimensions (i.e., volume > 1 cm3). The simulation used an equivalent cubic eight node finite elements mesh, and the materials properties were derived both empirically and numerically, from bulk material direct testing and simulated tests on scaffolds. The experimental validation was performed using poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers and 45 wt% nano hydroxyapatite fillers composites. By applying this methodology on three separate scaffold architectures with volumes larger than 1 cm3, the simulations overestimated the scaffold performance, resulting in 150–290% stiffer than average values obtained in the validation tests. The results mismatch highlighted the relevance of the lack of printing accuracy that is characteristic of the additive manufacturing process. Accordingly, a sensitivity analysis was performed on nine detected uncertainty sources, studying their influence. After the definition of acceptable execution tolerances and reliability levels, a design factor was defined to calibrate the methodology under expectable and conservative scenarios.

A review of additive manufacturing applications in ophthalmology

2021 ◽  
pp. 095441192110280
Author(s):  
Arivazhagan Pugalendhi ◽  
Rajesh Ranganathan
Keyword(s):  
Additive Manufacturing ◽  
Treatment Planning ◽  
Physical Object ◽  
Layer By Layer ◽  
Case Examples ◽  
Manufacturing Method ◽  
3D Cad ◽  
Stl File ◽  
Potential Applications ◽  
Manufacturing Applications

Additive Manufacturing (AM) capabilities in terms of product customization, manufacture of complex shape, minimal time, and low volume production those are very well suited for medical implants and biological models. AM technology permits the fabrication of physical object based on the 3D CAD model through layer by layer manufacturing method. AM use Magnetic Resonance Image (MRI), Computed Tomography (CT), and 3D scanning images and these data are converted into surface tessellation language (STL) file for fabrication. The applications of AM in ophthalmology includes diagnosis and treatment planning, customized prosthesis, implants, surgical practice/simulation, pre-operative surgical planning, fabrication of assistive tools, surgical tools, and instruments. In this article, development of AM technology in ophthalmology and its potential applications is reviewed. The aim of this study is nurturing an awareness of the engineers and ophthalmologists to enhance the ophthalmic devices and instruments. Here some of the 3D printed case examples of functional prototype and concept prototypes are carried out to understand the capabilities of this technology. This research paper explores the possibility of AM technology that can be successfully executed in the ophthalmology field for developing innovative products. This novel technique is used toward improving the quality of treatment and surgical skills by customization and pre-operative treatment planning which are more promising factors.

scholarly journals 3D Plotting of Silica/Collagen Xerogel Granules in an Alginate Matrix for Tissue-Engineered Bone Implants

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 830
Author(s):  
Sina Rößler ◽  
Andreas Brückner ◽  
Iris Kruppke ◽  
Hans-Peter Wiesmann ◽  
Thomas Hanke ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Bone Regeneration ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Viscoelastic Behavior ◽  
Matrix Phase ◽  
Patient Specific ◽  
Active Player ◽  
Alginate Concentration ◽  
Alginate Matrix

Today, materials designed for bone regeneration are requested to be degradable and resorbable, bioactive, porous, and osteoconductive, as well as to be an active player in the bone-remodeling process. Multiphasic silica/collagen Xerogels were shown, earlier, to meet these requirements. The aim of the present study was to use these excellent material properties of silica/collagen Xerogels and to process them by additive manufacturing, in this case 3D plotting, to generate implants matching patient specific shapes of fractures or lesions. The concept is to have Xerogel granules as active major components embedded, to a large proportion, in a matrix that binds the granules in the scaffold. By using viscoelastic alginate as matrix, pastes of Xerogel granules were processed via 3D plotting. Moreover, alginate concentration was shown to be the key to a high content of irregularly shaped Xerogel granules embedded in a minimum of matrix phase. Both the alginate matrix and Xerogel granules were also shown to influence viscoelastic behavior of the paste, as well as the dimensionally stability of the scaffolds. In conclusion, 3D plotting of Xerogel granules was successfully established by using viscoelastic properties of alginate as matrix phase.

scholarly journals QOLP-37. QUALITATIVE RESEARCH IN LOWER GRADE GLIOMA: UNDERSTANDING SIGNS, SYMPTOMS, AND DISEASE IMPACTS DURING EXPECTANT MANAGEMENT

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi206-vi206
Author(s):  
Audra Boscoe ◽  
Ted Wells ◽  
Christina Graham ◽  
Caitlin Pohl ◽  
Brooke Witherspoon ◽  
...  
Keyword(s):  
Treatment Options ◽  
Expectant Management ◽  
Signs And Symptoms ◽  
Molecular Therapy ◽  
Patient Specific ◽  
Lower Grade ◽  
Concept Elicitation ◽  
Post Surgery ◽  
Lower Grade Glioma ◽  
Isocitrate Dehydrogenase Mutation

Abstract BACKGROUND Patients with lower grade glioma (LGG) (i.e., grade II or III) have limited treatment options. After surgical resection of their tumor, patients will undergo either a period of expectant management (watch and wait) or treatment with adjuvant chemotherapy and/or radiotherapy. Approximately 80% of patients with LGG have an isocitrate dehydrogenase mutation, which is a viable target for molecular therapy. This offers a therapeutic intervention that could potentially delay the need for chemotherapy and/or radiotherapy in select patients. Several prognostic and patient-specific factors contribute to the decision to recommend expectant management, including concerns about the side effects of chemotherapy and radiotherapy. The aim of this project was to understand patients’ signs and symptoms during the expectant management period and how LGG impacts their lives. METHODS Concept elicitation interviews were conducted in the US with patients with LGG as well as key opinion leaders (KOLs) with experience treating patients with LGG. Interview data were analyzed using Atlas.ti, and patient data were reviewed against KOL data. RESULTS Seven patients with ≥ 3 months of expectant management experience and three KOLs were interviewed. During their expectant management periods, patients reported 12 signs/symptoms, mostly related to deficits in cognition. Patients reported 16 impacts across four categories, with a substantial proportion of the impacts identified as negatively affecting emotional function. The signs/symptoms and impacts reported by patients were generally also reported by KOLs. During expectant management, patients typically resume their original quality of life post-surgery, but may also experience anxiety. Patients and KOLs indicated a preference for expectant management and delaying chemotherapy or radiotherapy. CONCLUSIONS Patient and KOL interviews characterized the LGG experience and indicated a preference for expectant management, which may be supported by therapies that delay the initiation of chemotherapy and/or radiotherapy.

Measuring the Complexity of Additive Manufacturing Supply Chains

2017 ◽  
Author(s):  
Ardeshir Raihanian Mashhadi ◽  
Sara Behdad
Keyword(s):  
Supply Chain ◽  
Additive Manufacturing ◽  
Supply Chains ◽  
Product Complexity ◽  
Information Theoretic ◽  
Manufacturing Method ◽  
Management Domain ◽  
Information Theoretic Measures ◽  
Production Cycles ◽  
Supply Planning

Complexity has been one of the focal points of attention in the supply chain management domain, as it deteriorates the performance of the supply chain and makes controlling it problematic. The complexity of supply chains has been significantly increased over the past couple of decades. Meanwhile, Additive Manufacturing (AM) not only revolutionizes the way that the products are made, but also brings a paradigm shift to the whole production system. The influence of AM extends to product design and supply chain as well. The unique capabilities of AM suggest that this manufacturing method can significantly affect the supply chain complexity. More product complexity and demand heterogeneity, faster production cycles, higher levels of automation and shorter supply paths are among the features of additive manufacturing that can directly influence the supply chain complexity. Comparison of additive manufacturing supply chain complexity to its traditional counterpart requires a profound comprehension of the transformative effects of AM on the supply chain. This paper first extracts the possible effects of AM on the supply chain and then tries to connect these effects to the drivers of complexity under three main categories of 1) market, 2) manufacturing technology, and 3) supply, planning and infrastructure. Possible impacts of additive manufacturing adoption on the supply chain complexity have been studied using information theoretic measures. An Agent-based Simulation (ABS) model has been developed to study and compare two different supply chain configurations. The findings of this study suggest that the adoption of AM can decrease the supply chain complexity, particularly when product customization is considered.

scholarly journals MRI and Additive Manufacturing of Nasal Alar Constructs for Patient-specific Reconstruction

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Dafydd O. Visscher ◽  
Maureen van Eijnatten ◽  
Niels P. T. J. Liberton ◽  
Jan Wolff ◽  
Mark B. M. Hofman ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Patient Specific
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