scholarly journals Materials and Manufacturing Techniques for Polymeric and Ceramic Scaffolds Used in Implant Dentistry

2021 ◽  
Vol 5 (3) ◽  
pp. 78
Author(s):  
Mutlu Özcan ◽  
Dachamir Hotza ◽  
Márcio Celso Fredel ◽  
Ariadne Cruz ◽  
Claudia Angela Maziero Volpato

Preventive and regenerative techniques have been suggested to minimize the aesthetic and functional effects caused by intraoral bone defects, enabling the installation of dental implants. Among them, porous three-dimensional structures (scaffolds) composed mainly of bioabsorbable ceramics, such as hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) stand out for reducing the use of autogenous, homogeneous, and xenogenous bone grafts and their unwanted effects. In order to stimulate bone formation, biodegradable polymers such as cellulose, collagen, glycosaminoglycans, polylactic acid (PLA), polyvinyl alcohol (PVA), poly-ε-caprolactone (PCL), polyglycolic acid (PGA), polyhydroxylbutyrate (PHB), polypropylenofumarate (PPF), polylactic-co-glycolic acid (PLGA), and poly L-co-D, L lactic acid (PLDLA) have also been studied. More recently, hybrid scaffolds can combine the tunable macro/microporosity and osteoinductive properties of ceramic materials with the chemical/physical properties of biodegradable polymers. Various methods are suggested for the manufacture of scaffolds with adequate porosity, such as conventional and additive manufacturing techniques and, more recently, 3D and 4D printing. The purpose of this manuscript is to review features concerning biomaterials, scaffolds macro and microstructure, fabrication techniques, as well as the potential interaction of the scaffolds with the human body.

2019 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Galih Paramarta ◽  
Eny Inayati

Background: The low levels of patient satisfaction and confidence in the restoration of the gingival resorption results in impaired quality of life in both functional and psychosocial aspects. It is necessary to manufacture a dental restoration to restore the mastication, phonetic, and aesthetic functions associated with soft tissue repair. Manufacture of gingiva ceramic restorations which are believed to be an alternative to restore the aesthetic function and harmonization of the patient’s teeth. In terms of manufacturing techniques, this restoration has a level of difficulty in achieving a balance between “White aesthetic” and “aesthetic pink”. Objective: This study aims to provide knowledge to the reader of Manufacturing Technique of Metal Ceramic Restoration with Implant-Abutment at Gingival Resorption Case. Reviews: Gingiva ceramic restorations can be used to create esthetic implant-supported restorations when bone and gingival tissues are deficient and surgical replacement of such tissues is not possible. Dental technicians should be able to analyze the three-dimensional shapes of gingival anatomy, color, texture, smile components, the balance of the “pink aesthetic” and “white aesthetic”. Conclusion: Manufacturing Technique of Metal Ceramic Restoration with Implant-Abutment at Gingival Resorption Case including the manufacture of metal coping, oxidation, application of opaque coating, application of the first “white aesthetic” ceramics (Opaque Dentine, Dentine, Enamel and transpa on crown coping restorations), Application of opaque gingiva layer, gingival ceramics build-up "pink aesthetics”, first firing, followed by correction build-up, and second firing, and ends with the glazing process.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.


2014 ◽  
Vol 39 (17) ◽  
pp. 5162 ◽  
Author(s):  
Suk-Heung Song ◽  
Kibeom Kim ◽  
Sung-Eun Choi ◽  
Sangkwon Han ◽  
Ho-Suk Lee ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3149
Author(s):  
Angelika Zaszczyńska ◽  
Maryla Moczulska-Heljak ◽  
Arkadiusz Gradys ◽  
Paweł Sajkiewicz

Tissue engineering (TE) scaffolds have enormous significance for the possibility of regeneration of complex tissue structures or even whole organs. Three-dimensional (3D) printing techniques allow fabricating TE scaffolds, having an extremely complex structure, in a repeatable and precise manner. Moreover, they enable the easy application of computer-assisted methods to TE scaffold design. The latest additive manufacturing techniques open up opportunities not otherwise available. This study aimed to summarize the state-of-art field of 3D printing techniques in applications for tissue engineering with a focus on the latest advancements. The following topics are discussed: systematics of the available 3D printing techniques applied for TE scaffold fabrication; overview of 3D printable biomaterials and advancements in 3D-printing-assisted tissue engineering.


Author(s):  
Matthew N. Rush ◽  
Christina Salas ◽  
Lorraine Mottishaw ◽  
Damian Fountain ◽  
Deana Mercer

Abstract Background Ligament reconstruction, as a surgical method used to stabilize joints, requires significant strength and tissue anchoring to restore function. Historically, reconstructive materials have been fraught with problems from an inability to withstand normal physiological loads to difficulties in fabricating the complex organization structure of native tissue at the ligament-to-bone interface. In combination, these factors have prevented the successful realization of nonautograft reconstruction. Methods A review of recent improvements in additive manufacturing techniques and biomaterials highlight possible options for ligament replacement. Description of Technique In combination, three dimensional-printing and electrospinning have begun to provide for nonautograft options that can meet the physiological load and architectures of native tissues; however, a combination of manufacturing methods is needed to allow for bone-ligament enthesis. Hybrid biofabrication of bone-ligament tissue scaffolds, through the simultaneous deposition of disparate materials, offer significant advantages over fused manufacturing methods which lack efficient integration between bone and ligament materials. Results In this review, we discuss the important chemical and biological properties of ligament enthesis and describe recent advancements in additive manufacturing to meet mechanical and biological requirements for a successful bone–ligament–bone interface. Conclusions With continued advancement of additive manufacturing technologies and improved biomaterial properties, tissue engineered bone-ligament scaffolds may soon enter the clinical realm.


Author(s):  
Akira Yamada ◽  
Fuminori Niikura ◽  
Koji Ikuta

Biodegradable polymers are employed in medicine and its further application is expected with eagerness. But the lack of an appropriate processing method retards the progress. To overcome this problem, we have developped a novel three-dimensional microfabrication system. The system design allows us the processing of the free three-dimensional micro-level forms by stacking up melted polymers from the nozzle. Different from the conventional method, we adopted a batch process to supply materials in order to eliminate the prior process that required toxic solvents. In addition, it is possible to handle almost all biodegradable thermoplastic resins by adopting this system. A single layer from the piled-up layers of extruded lines was observed to evaluate the resolution. The lateral and depth resolutions attained are 40 μm and 45 μm, respectively. Biodegradable polymers enable three-dimensional microstructures such as micro-pipes, micro-bends, and micro-coil springs to be manufactured in less than 15 min. The biocompatibility of the newly fabricated structure was evaluated using a cell line (PC12). For this purpose, a small vessel, with a transparent base, was fabricated using PLA and cells were cultivated in it. The results were then compared with the results obtained using the standard method. The mechanical strength of our microstructures was evaluated using a tensile strength test. The tensile strength of the microstructure was lower than the one obtained from the conventional method, but has enough strength for fabrication of medical devices. Our system renders it possible to produce toxic-free, as well as transparent and leakage-free devices. Our system is expected to have potential applications in optimum design and fabrication of implantable devices, especially in tissue engineering.


Author(s):  
Monika Maria Stumpp ◽  
Claudio Calovi Pereira

The development of design activity uses technical suports that allow the architect to record the evolution of your idea or communication with it. Historically, the support that has been used is the graphical representation, which, as a intelligence technology, joins with the creative and cognitive processes of the individual, allowing communication with their imagination and also to all individuals involved in projecting. The representations graphically materialized, calls drawing,  are important in the practice of architecture because they represent the evolution of the design process. The drawing means the way in which design is conducted, tested, controlled and ultimately appears performed. In this context the drawings of the Renaissance architect Andrea Palladio play a special role in the history of architecture, because it makes clear how he understood and thought the architecture. At that time, the graphical representation of the space acquired an importance that had not previously, incorporating a greater number of alternative representation, highlighting the aesthetic concerns and the current building techniques. A lot of drawings produced by Palladio, shows how he was deeply convinced of eloquence and priority of images to understand the architecture, more than any other form of discursive explanation. In this sense, this work investigates the drawings of Palladio as a tool at the process of design solutions translation. The reading of the project through the design has been used to study designs and architectural objects or certain styles or specific authorship of an architect. Here the method is used for reading the project of Villa Pisani in Bagnolo (1542). Using two and three dimensional drawings, represented by plan, section and volumetry, it is intended to make explicit certain aspects underlying the architectural work, as questions of proportion and symmetry. It is expected that, at the work of Palladio, this method allows to compare and understand drawings, in order to analyze mutations and replications and  search of new meanings, readings and interpretations.


1998 ◽  
Vol 120 (2) ◽  
pp. 205-214 ◽  
Author(s):  
C. M. Rhie ◽  
A. J. Gleixner ◽  
D. A. Spear ◽  
C. J. Fischberg ◽  
R. M. Zacharias

A multistage compressor performance analysis method based on the three-dimensional Reynolds-averaged Navier-Stokes equations is presented in this paper. This method is an average passage approach where deterministic stresses are used to ensure continuous physical properties across interface planes. The average unsteady effects due to neighboring blades and/or vanes are approximated using deterministic stresses along with the application of bodyforces. Bodyforces are used to account for the “potential” interaction between closely coupled (staged) rows. Deterministic stresses account for the “average” wake blockage and mixing effects both axially and radially. The attempt here is to implement an approximate technique for incorporating periodic unsteady flow physics that provides for a robust multistage design procedure incorporating reasonable computational efficiency. The present paper gives the theoretical development of the stress/bodyforce models incorporated in the code, and demonstrates the usefulness of these models in practical compressor applications. Compressor performance prediction capability is then established through a rigorous code/model validation effort using the power of networked workstations. The numerical results are compared with experimental data in terms of one-dimensional performance parameters such as total pressure ratio and circumferentially averaged radial profiles deemed critical to compressor design. This methodology allows the designer to design from hub to tip with a high level of confidence in the procedure.


2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000159-000165
Author(s):  
M. Wilson ◽  
H. Anderson ◽  
J. Fellows ◽  
C. Lewinsohn

Heat dissipation has become a major hurdle for the electronics industry, especially as higher performance integrated circuits are being developed for the power industry. Two of the primary hurdles in dissipating this heat are:The thermal contact resistance between the IC and the cooling device.The ability to effectively spread the heat, such that traditional cooling technologies can be effective.By selecting ceramic materials that are thermo-mechanically matched (CTE) to IC materials, the proposed heat plate can be directly bonded by typical solder or braze techniques to the back-side of the IC. This eliminates thermal resistances due to contact and thermal interface materials. Within these heat plates, a three dimensional network of gas channels and fluid wicks spread the high-flux heat loads from localized hot spots to the surrounding regions via phase change fluids and mass transport. Like traditional heat pipes, these heat plates operate at nearly uniform temperature due to the phase change. The internal networks provide for multidimensional heat and mass flow, increasing their dissipating capability. By using matched ceramic materials, and the inclusion of a heat plate, these primary hurdles for heat dissipation can be mitigated. The performance of prototypical planar heat plates will be presented.


2017 ◽  
Vol 10 ◽  
pp. 93-106 ◽  
Author(s):  
M.K. Teixeira de Brito ◽  
D.B. Teixeira de Almeida ◽  
A.G. Barbosa de Lima ◽  
L. Almeida Rocha ◽  
E. Santana de Lima ◽  
...  

This work aims to study heat and mass transfer in solids with parallelepiped shape with particular reference to drying process. A transient three-dimensional mathematical model based on the Fick ́s and Fourier ́s Laws was developed to predict heat and mass transport in solids considering constant physical properties and convective boundary conditions at the surface of the solid. The analytical solution of the governing equations was obtained using the method of separation of variables. The study was applied in the drying of common ceramic bricks. Predicted results of the heating and drying kinetics and the moisture and temperature distributions inside the material during the process, are compared with experimental data and good agreement was obtained. It has been found that the vertices of the solid dry and heat first. This provokes thermal and hydric stresses inside the material, which may compromise the quality of the product after drying.


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