scholarly journals 3D Printed Multi-material Medical Phantoms for Needle-tissue Interaction Modelling of Heterogeneous Structures

2021 ◽  
Vol 18 (2) ◽  
pp. 346-360
Author(s):  
Jun Yin ◽  
Manqi Li ◽  
Guangli Dai ◽  
Hongzhao Zhou ◽  
Liang Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Medical Training ◽  
Thermoplastic Polyurethane ◽  
Acrylonitrile Butadiene Styrene ◽  
Tactile Feedback ◽  
Patient Specific ◽  
Insertion Force ◽  
Silicone Grease ◽  
Manufacturing Method

AbstractThe fabrication of multi-material medical phantoms with both patient-specificity and realistic mechanical properties is of great importance for the development of surgical planning and medical training. In this work, a 3D multi-material printing system for medical phantom manufacturing was developed. Rigid and elastomeric materials are firstly combined in such application for an accurate tactile feedback. The phantom is designed with multiple layers, where silicone ink, Thermoplastic Polyurethane (TPU), and Acrylonitrile Butadiene Styrene (ABS) were chosen as printing materials for skin, soft tissue, and bone, respectively. Then, the printed phantoms were utilized for the investigation of needle-phantom interaction by needle insertion experiments. The mechanical needle-phantom interaction was characterized by skin-soft tissue interfacial puncture force, puncture depth, and number of insertion force peaks. The experiments demonstrated that the manufacturing conditions, i.e. the silicone grease ratio, interfacial thickness and the infill rate, played effective roles in regulating mechanical needle-phantom interaction. Moreover, the influences of material properties, including interfacial thickness and ultimate stress, on needle-phantom interaction were studied by finite element simulation. Also, a patient-specific forearm phantom was printed, where the anatomical features were acquired from Computed Tomography (CT) data. This study provided a potential manufacturing method for multi-material medical phantoms with tunable mechanical properties and offered guidelines for better phantom design.

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.

Effects of poly(styrene-co-maleic anhydride) on the performance of LGF/TPU/ABS composites

2016 ◽  
Vol 23 (5) ◽  
pp. 475-480 ◽  
Author(s):  
Wulei Zhou ◽  
Jian Xiao ◽  
Fang Liu ◽  
Shuhao Qin
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Glass Fiber ◽  
Thermoplastic Polyurethane ◽  
Testing Machine ◽  
Acrylonitrile Butadiene Styrene ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Glass Fiber Reinforced ◽  
Long Glass Fiber

AbstractA series of long glass fiber-reinforced thermoplastic polyurethane (TPU) elastomers and acrylonitrile-butadiene-styrene (ABS) copolymer (LGF/TPU/ABS) composites were prepared using self-designed impregnation device. Poly(styrene-co-maleic anhydride) was employed to increase the compatibility between glass fiber and matrix resin and thus obtain the excellent properties of composites. The dynamic mechanical properties of the composites have been investigated using dynamic mechanical thermal analysis. The results indicated that the storage modulus of the composites gradually increases and then decreases with increasing compatibilizer content. In addition, the low temperature peak of the composites shifts to higher temperature with increasing compatibilizer content. The thermal properties of the composites were studied by thermogravimetric analyzer. In addition, the morphology and mechanical properties of the composites are investigated by scanning electron microscopy, a universal testing machine, and a ZBC-4 Impact Pendulum.

scholarly journals Sandwich Multi-Material 3D-Printed Polymers: Influence of Aging on the Impact and Flexure Resistances

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4030
Author(s):  
Ana C. Pinho ◽  
Ana P. Piedade
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Sandwich Structures ◽  
Artificial Saliva ◽  
Thermoplastic Polyurethane ◽  
Acrylonitrile Butadiene Styrene ◽  
Flexural Stress ◽  
Transverse Impact ◽  
Softening Effect ◽  
The Impact

With the advances in new materials, equipment, and processes, additive manufacturing (AM) has gained increased importance for producing the final parts that are used in several industrial areas, such as automotive, aeronautics, and health. The constant development of 3D-printing equipment allows for printing multi-material systems as sandwich specimens using, for example, double-nozzle configurations. The present study aimed to compare the mechanical behavior of multi-material specimens that were produced using a double-nozzle 3D printer. The materials that were included in this study were the copolymer acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), poly(methyl methacrylate) (PMMA), and thermoplastic polyurethane (TPU). The configuration of the sandwich structures consisted of a core of TPU and the outer skins made of one of the other three materials. The mechanical behavior was evaluated through three-point bending (3PB) and transverse impact tests and compared with mono-material printed specimens. The effect of aging in artificial saliva was evaluated for all the processed materials. The main conclusion of this study was that the aging process did not significantly alter the mechanical properties for mono-materials, except for PMMA, where the maximum flexural stress decreased. In the sandwich structures, the TPU core had a softening effect, inducing a significant increase in the resilience and resistance to transverse impact. The obtained results are quite promising for applications in biomedical devices, such as protective mouthguards or teeth aligners. In these specific applications, the changes in the mechanical properties with time and with the contact of saliva assume particular importance.

scholarly journals Tests of mechanical properties of semicrystalline and amorphous polymeric materials produced by 3D printing

2019 ◽  
Vol 254 ◽  
pp. 06003
Author(s):  
Piotr Sikora ◽  
Adam Gnatowski ◽  
Rafał Gołębski
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Ethylene Terephthalate ◽  
Visual Analysis ◽  
Thermoplastic Polyurethane ◽  
Polymeric Materials ◽  
Acrylonitrile Butadiene Styrene ◽  
Poly Lactic Acid ◽  
Pressing Method ◽  
Butadiene Styrene

The article presents the results of tests of physical properties of samples from semi-crystalline and amorphous polymeric materials produced using 3D printing. Samples were produced using 3D printing technology on the SIGNAL -ATMAT printer. The following polymeric materials were used to make the samples: TPU thermoplastic polyurethane elastomer, ABS acrylonitrile-butadiene-styrene copolymer, Laywood, PET ethylene terephthalate, PLA poly (lactic acid). The materials were tested for their mechanical properties. The hardness was determined by the Shore method and the ball-pressing method. The tensile strength also was determined. The research samples were subjected to visual analysis on a Keyence microscope to analyze the breakthrough site.

scholarly journals Association Between Pain in Knee Osteoarthritis and Mechanical Properties of Soft Tissue Around Knee Joint

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 14599-14607
Author(s):  
Jianan Wu ◽  
Zhihui Qian ◽  
Ruixia Xu ◽  
Jing Liu ◽  
Luquan Ren ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Soft Tissue ◽  
Knee Joint ◽  
Knee Osteoarthritis

scholarly journals Concomitant control of mechanical properties and degradation in resorbable elastomer-like materials using stereochemistry and stoichiometry for soft tissue engineering

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mary Beth Wandel ◽  
Craig A. Bell ◽  
Jiayi Yu ◽  
Maria C. Arno ◽  
Nathan Z. Dreger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Soft Tissue ◽  
Tissue Regeneration ◽  
Biological Tissues ◽  
Soft Tissue Regeneration ◽  
Soft Tissue Engineering ◽  
Degradation Properties ◽  
Enhance Cell Adhesion

AbstractComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical, and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.

scholarly journals True Kinematic Alignment Is Applicable in 44% of Patients Applying Restrictive Indication Criteria—A Retrospective Analysis of 111 TKA Using Robotic Assistance

2021 ◽  
Vol 11 (7) ◽  
pp. 662
Author(s):  
Kim Huber ◽  
Bernhard Christen ◽  
Sarah Calliess ◽  
Tilman Calliess
Keyword(s):  
Soft Tissue ◽  
Retrospective Analysis ◽  
Patient Specific ◽  
Kinematic Alignment ◽  
Postoperative Phase ◽  
Robotic Assistance ◽  
Component Position ◽  
Joint Stability ◽  
Robotic Assisted ◽  
Primary Tkas

Introduction: Image-based robotic assistance appears to be a promising tool for individualizing alignment in total knee arthroplasty (TKA). The patient-specific model of the knee enables a preoperative 3D planning of component position. Adjustments to the individual soft-tissue situation can be done intraoperatively. Based on this, we have established a standardized workflow to implement the idea of kinematic alignment (KA) for robotic-assisted TKA. In addition, we have defined limits for its use. If these limits are reached, we switch to a restricted KA (rKA). The aim of the study was to evaluate (1) in what percentage of patients a true KA or an rKA is applicable, (2) whether there were differences regarding knee phenotypes, and (3) what the differences of philosophies in terms of component position, joint stability, and early patient outcome were. Methods: The study included a retrospective analysis of 111 robotic-assisted primary TKAs. Based on preoperative long leg standing radiographs, the patients were categorized into a varus, valgus, or neutral subgroup. Initially, all patients were planned for KA TKA. When the defined safe zone had been exceeded, adjustments to an rKA were made. Intraoperatively, the alignment of the components and joint gaps were recorded by robotic software. Results and conclusion: With our indication for TKA and the defined boundaries, “only” 44% of the patients were suitable for a true KA with no adjustments or soft tissue releases. In the varus group, it was about 70%, whereas it was 0% in the valgus group and 25% in the neutral alignment group. Thus, significant differences with regard to knee morphotypes were evident. In the KA group, a more physiological knee balance reconstructing the trapezoidal flexion gap (+2 mm on average laterally) was seen as well as a closer reconstruction of the surface anatomy and joint line in all dimensions compared to rKA. This resulted in a higher improvement in the collected outcome scores in favor of KA in the very early postoperative phase.

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