Objectives: The aim of the current study is to establish the reliability of linear cephalometric measurements made on mandibles and their respective 3D printed models created from different voxel resolutions from a cone beam CT machine. Materials and methods: Ten dry mandibles obtained from the Department of Oral Pathology, Radiology and Medicine at The University of Iowa College Of Dentistry were used for this study. All mandibles were scanned on the i-CAT FLX cone beam CT machine (Imaging Sciences International, LLC, Pennsylvania, USA) using voxel resolutions of .30mm, .25mm and .20 mm in a 16cm x 8cm field of view using 360° rotation. The 3D models were reconstructed and saved as .STL files using 3D Slicer software and send to a 3D printer for printing. Two observers measured the 10 mandibles and 30 3D printed models. The measurement were repeated on 50% of the samples after at least one week interval. Cronbach’s alpha and intraclass correlation coefficient were calculated to measure reliability. Results: Good to excellent interobserver and intraobserver reliability was achieved across most of the measurements. There was no difference in reliability across models made from different voxel sizes. Conclusion: The current study successfully showed that the reliability of measurements made on 3D printed models of dry skull mandibles created using fused deposition modeling technique using images of different voxel sizes from an i-CAT FLX CBCT machine are valid, reproducible, and reliable and can be used for diagnostic and clinical purposes.

Controlled drug delivery systems have been utilized to enhance the therapeutic effects of many current drugs by effectively delivering drugs in a time-dependent and repeatable manner. The ability to control the delivery of drugs, whether through sequential, instantaneous, sustained, delayed and/or enhanced release has the potential to provide effective dosing regimens with enhanced therapeutic effects for a plethora of diseases and injuries. For instance, such systems can enhance anti-tumoral responses or, alternatively, promoting tissue regeneration. The current need for organ and tissue replacement, repair and regeneration for patients is continually growing such that supply is not meeting the high demand primarily due to a paucity of donors as well as biocompatibility issues that lead to immune rejection of the transplant. To overcome this problem, scientists working in the field of tissue engineering and regenerative medicine have investigated the use of scaffolds as an alternative to transplantation. These scaffolds are designed to mimic the extracellular matrix (ECM) by providing structural support as well as promoting attachment, proliferation, and differentiation with the goal of yielding functional tissues or organs. Continued advancement and hybrid approaches using different material combinations and printing methodologies will further advance the progress of 3D printing technologies toward developing scaffolds, and other implantable drug delivery devices, capable of being utilized in the clinic. Such advancements will not only make inroads into improving structural integrity of implantable devices but will also provide platforms for controlled drug delivery from such devices. The primary focus of this thesis will be on controlled drug delivery as well as the integration of controlled drug delivery into 3D printed devices aimed at promoting tissue regeneration. We initially assessed the efficacy of a controlled drug delivery system for the treatment of cancer using on-demand, and sustained, release of an anticancer drug, doxorubicin (DOX), for the treatment of melanoma in a murine model. Using a melanoma model, we investigated the antitumor potential of combining ultrasound (US) with poly(lactic-co-glycolic acid) (PLGA) microspheres loaded with DOX. An in vitro release assay demonstrated an ability of US to affect the release kinetics of DOX from DOX-loaded PLGA microspheres by inducing a 12% increase in rate of release where this treatment resulted in synergistic tumor cell (B16-F10 melanoma cells) killing. Melanoma-bearing mice treated intratumorally with DOX (8 µg)-loaded microspheres and subjected to US treatment at the tumor site were shown to significantly extended survival compared to untreated mice or mice subjected to either treatment alone. The synergistic increase in survival of melanoma-challenged mice treated with the combination of US and DOX-loaded microspheres implicates a promising additional tool for combatting an otherwise currently incurable cancer. We then further investigated other novel control drug delivery systems which included a 3D printed device (tube) for the purposes of sequential drug delivery. 3D printed hollow alginate tubes were fabricated through co-axial bioprinting and then injected with PLGA to provide sequential release of distinct fluorescent dyes (model drugs), where fluorescein was initially released from alginate followed by the delayed release (up to 55 h) of rhodamine B in PLGA. With an alginate shell and a PLGA core, the fabricated tubes showed no cytotoxicity when incubated with the human embryonic kidney (HEK293) cell line or bone marrow stromal stem cells (BMSC). Microscale printing through two-photon polymerization (2PP) was then investigated for controlled drug delivery potential. Poly(ethylene glycol) dimethacrylate (PEGDMA) devices were fabricated using a Photonic Professional GT two-photon polymerization system while rhodamine B was homogenously entrapped inside the polymer matrix during photopolymerization. These devices were printed with varying porosity and morphology and using varying printing parameters such as slicing and hatching distance. Overall, tuning the hatching distance, slicing distance, and pore size of the fabricated devices provided control of rhodamine B release due to resulting changes in the motility of the small molecule and its access to structure edges. In general, increased spacing provided higher drug release while smaller spacing resulted in some occlusion, preventing media infiltration and thus resulting in reduced drug release. 2PP was further explored for its ability to tailor topographical cues in addition to controlled drug release. These physical cues, similar to those of the ECM, have been seen to promote differentiation. With 2PP, we explored microscale topographies with nanoscale precision, where different star size topographies were fabricated. It was observed that the smallest star size topographies differentiated human iPSCs towards the endoderm and mesoderm germ layer. Integrating the facility for controlled drug release into 3D printed devices provides a demand for constructs that not only need to fulfill their purpose of temporarily substituting for the missing tissue at the site of injury, but also providing the necessary cues to promote appropriate tissue regeneration. With 3D printing technology, novel drug delivery constructs were fabricated and tested to appraise functionality such as the ability to control drug delivery and the ability to function as a non-toxic medium for cellular attachment, proliferation, and forced differentiation.

In this study, a previously designed passive dynamic walker (PDW) is built out of aluminum and plastic. The aim of the study was to produce an asymmetrical PDW and to compare the results to a computer simulation to validate the mathematical model. It also aimed at identifying the limitations of using additive manufacturing to create components for a PDW as well as gain insights on asymmetric systems. Beginning with a five mass kneed model, parameters were varied to produce up to a nine mass kneed model solution. The nine mass model allows more variability in added mass locations and separates the zeroth, first, and second moments of inertia. To validate asymmetric gait, step length and step time of the prototype were compared to the simulation. The walker, unable to produce a steady gait, failed to match the asymmetric simulation. More than four times the amount of symmetric data was found compared to asymmetric data. Successful runs of symmetric gaits were approximately double than for asymmetric gaits. The reason for unequal successes is thought to be due to greater instability of asymmetric systems. This instability is thought to be due to inertia from a constant state of hanging motion. 3D printing proved useful in simplifying components and reducing waste but the polymers used did not have enough strength when mass was added to the system. Joining differing materials on the legs was difficult to keep in place. A smaller more robust design could solve these problems. This study focused on understanding physically asymmetric PDWs. These simple robots separate the neurological and mechanical controls of walking and are advantageous for studying physical parameters of human gait. Once a reliable asymmetric walker is built, further research could alter the foot shape or knee location to reverse the process, thus having a PDW walk symmetric. Once a walker is successfully reverted from walking asymmetrical to symmetrical, these parameters could be then applied to human subjects. An example of this would be for prosthetic foot design.

Orientador: Gustavo Franco Barbosa / Resumo: Há décadas, a engenharia de tecidos passou a ser considerada em diversas aplicações, um tratamento médico adequado, devido suas excelentes vantagens, além da escassez de órgãos e disponibilidade de tecidos para serem transplantados. Conhecida como regeneração de novos tecidos, esse ramo da engenharia biomédica fundamentada nos conhecimentos de Biologia, Química e Física, torna-se uma grande alternativa quando tratamentos farmacêuticos convencionais não são mais aplicáveis, utilizando-se de três tipos básicos de ferramentas: célula, scaffolds e fator de crescimento. Dessa forma, esse trabalho tem como propósito principal a manufatura de scaffolds, utilizando a tecnologia de impressão 3D a partir de polímeros termoplásticos biodegradáveis e fosfatos de cálcio (em escala micrométrica), com o objetivo de se obter estruturas 3D complexas e porosas que apresentem propriedades mecânicas adequadas (em relação a ossos) e interconectividade estruturada entre os poros. Com os modelos 3D dos scaffolds projetados, e a seleção e preparação dos materiais envolvidos, foram realizados ajustes de parâmetros para o processamento dos scaffolds e posterior fabricação dos mesmos, mediante o uso da tecnologia de manufatura aditiva com bioimpressora de microextrusão que utiliza sistema de distribuição pneumático para extrusão contínua do material. Por fim os scaffolds foram caracterizados por técnica de análise de propriedade mecânica por ensaio de compressão e as amostras avaliadas pelo método de M... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: For decades, tissue engineering has come to be considered in several applications, an adequate medical treatment, due to its excellent advantages, in addition to the scarcity of organs and the availability of tissues to be transplanted. Known as regenerating of new tissues, this branch of biomedical engineering grounded in the knowledge of biology, chemistry and physics, becomes a great alternative when conventional pharmaceutical treatments are no longer applicable, using three basic types of tools: cell, scaffolds and growth factor. Thus, the main purpose of this work is the manufacture of scaffolds, using the technology of 3D printing from biodegradable thermoplastic polymers and calcium phosphates (in micrometric scale), with the objective of obtaining complex and porous 3D structures that present properties mechanical (in relation to bones) and structured interconnectivity between the pores. With the 3D models of the scaffolds designed, and the selection and preparation of the materials involved, adjustments were made to the processing parameters of the scaffolds and their subsequent manufacture, using the technology of additive manufacturing with microextrusion bioprinter that uses pneumatic distribution system for continuous extrusion of the material. Finally, the scaffolds were characterized by technique of mechanical property analysis by compression test and the samples evaluated by Scanning Electron Microscopy (SEM) method. / Mestre

The emergence of desktop ‘3D printing’ is not only a technological development, but equally a social and economic phenomenon that actively (and often contentiously) co-produces the material and ideological infrastructures it occupies. Reflecting wider momentum toward digital-material convergence, the current “revolution” in desktop digital fabrication is fundamentally attributable to the efforts of decentralized Maker and DIY communities who, connected through digital networks, practice citizen-led technological experimentation and occupy novel spaces for innovation and entrepreneurship. Employing hybrid qualitative methods that include Critical Making, this research explores the following themes: rhetoric versus reality, the divisive notion of ‘digital craft’, perceptions of authenticity, as well as cultural momentum manifested in decentralization, convergence, stratification, and iteration. An overarching theme emerges: 3D printing is a fluid phenomenon – in literal, metaphorical, technological and cultural ways.

The emergence of desktop ‘3D printing’ is not only a technological development, but equally a social and economic phenomenon that actively (and often contentiously) co-produces the material and ideological infrastructures it occupies. Reflecting wider momentum toward digital-material convergence, the current “revolution” in desktop digital fabrication is fundamentally attributable to the efforts of decentralized Maker and DIY communities who, connected through digital networks, practice citizen-led technological experimentation and occupy novel spaces for innovation and entrepreneurship. Employing hybrid qualitative methods that include Critical Making, this research explores the following themes: rhetoric versus reality, the divisive notion of ‘digital craft’, perceptions of authenticity, as well as cultural momentum manifested in decentralization, convergence, stratification, and iteration. An overarching theme emerges: 3D printing is a fluid phenomenon – in literal, metaphorical, technological and cultural ways.

This thesis provides investigation into the interaction between quartz lamp emitters and polyether ether ketone (PEEK) powder. Calculations and experiments concerning the conductivity and emissivity of the powder at various temperatures are performed. The thermal profile of the emitter on a flat powder bed is captured using thermal imaging. The effect of exposing a pile of powder to the emitter and the subsequent thermal gradient through the pile is measured and analyzed. Based on these results, ramifications for the application of these emitters to selective laser sintering (SLS) machines for processing high temperature polymers such as PEEK are discussed. / text

ABSTRACT Emerging 3D printing technologies bring with it the potential to transform everyday consumers into manufacturers of every product imaginable. However, this impending wave of newfound technological capability is bound to crash against our present conventional system of laws and regulations. In this paper, the strengths and weaknesses of our current intellectual property framework are examined, and its ability to tackle the future 3D printing market is assessed. Particular attention is paid to our modern formation of copyright and patent law, including an analysis of the Digital Millennium Copyright Act (DMCA), the Repair-Reconstruction Doctrine and other substantial legal protocol. The legal battle between the Napster file-sharing service and the larger music industry is also explored, as it provides key insight into similar intellectual property divergences that may soon drive a stake between 3D printing businesses and more traditional manufacturers of physical goods. Finally, this paper suggests modifications to be made towards traditional sales models, the Repair-Reconstruction Doctrine, the implementation of the DMCA protections, and our application of the Fair Use Doctrine.

No description available.

As cirurgias de reconstrução parcial ou total de orelha são um desafio na medicina, exigindo técnicas complexas e qualificadas, sendo as mais utilizadas àquelas que fazem uso de material autógeno (cartilagem da costela do próprio paciente). Trata-se de um processo artesanal em que o cirurgião deve esculpir manualmente a cartilagem para formar o modelo tridimensional da orelha, denominado framework, dessa forma, o resultado final depende, principalmente, da habilidade do cirurgião plástico. Tendo isso em vista, busca-se, neste trabalho, empregar as tecnologias computacionais utilizadas no Design Virtual para auxiliar o planejamento cirúrgico, utilizando digitalização tridimensional e fabricação digital para aprimorar o resultado da técnica de reconstrução auricular. A metodologia proposta sugere a digitalização tridimensional do paciente e, a partir disso, são projetados templates cirúrgicos para auxiliar a modelagem e o posicionamento do framework. A aplicação cirúrgica valida alguns pontos e possibilita o estudo de melhorias em determinados templates, utilizados então em outras duas reconstruções, obtendo-se resultados positivos. Assim, o uso do Design Virtual mostra-se confiável e útil na cirurgia de reconstrução auricular, levando à melhoria no planejamento e, assim, diminuição do tempo cirúrgico, sem riscos ou complicações ao paciente e com melhores resultados anatômicos. / The partial or total reconstruction of ear is a challenge in plastic surgery, requiring complex and skilled techniques. The most successful reconstructions use autogenous material (cartilage from the patient's own rib). It is a handmade process in which the surgeon must manually sculpt the cartilages to form the three-dimensional model of the ear, usually called as framework. Considering this, the final result depends mainly on the plastic surgeon's skill. In this scenario, the aim of this research is employ computer technologies used in Virtual Design to aid surgical planning, using three-dimensional scanning and digital manufacturing to improve the result of ear reconstruction technique. The proposed methodology suggests surgical templates, based on 3D patient scan, designed to assist the modeling and positioning of the framework. The surgical application validates some points and allows the study of improvements in certain templates, then used in other two surgeries, with positive results. Thus, the use of Virtual Design proves to be reliable and useful in ear reconstruction surgery, leading to improved planning and decreasing surgical time, without any risks or complications for the patient and with better anatomical results.