Solutions based on three-dimensional technologies for the practice and teaching of biomedical sciences

Introduction: Three-dimensional printing is one of the technologies that promote change at an economic and social level, and one of the fundamental elements of industry 4.0. It has enormous potential for the future of medicine, establishing itself as a new paradigm. Despite its advantages, its use in our environment is incipient. Objective: To design and develop solutions based on three-dimensional technologies for the teaching and practice of biomedical sciences. Materials and methods: A technological development investigation was carried out between the Center for Assisted and Sustainable Manufacturing of the University of Matanzas and Matanzas University of Medical Sciences, between September 2019 and July 2022. The designs and fabrications were made from the acquisition of computed tomography images, or from a surface scanner, which were then processed, converted into Standard Tessellation Language format, printed, and post-processed. Virtual designs were developed using computer-aided design software. Results: Various solutions were developed including prototypes: biomodels for craniosynostosis repair and anatomical figures, custom cranial prosthesis mold, hand prosthesis, O2 line splitters, tissue scaffolds, syringe gun, face shields, breast prosthesis; autologous restoration mold and tissue expander. Conclusions: In all areas of application of this technology in medicine―except the printing of medicines, in the current context―, it is feasible to obtain solutions in the territory of Matanzas. It is therefore imperative that managers and the medical community in general, begin to acquire awareness, knowledge, and experience to ensure the optimal use of this technology.

Introducción: La impresión tridimensional es una de las tecnologías que promueve el cambio a nivel económico y social, y uno de los elementos fundamentales de la industria 4.0. Asimismo, constituye un enorme potencial para el futuro de la medicina, estableciéndose como un nuevo paradigma. A pesar de sus ventajas, su explotación en nuestro medio es incipiente. Objetivos: Diseñar y desarrollar soluciones basadas en tecnologías tridimensionales para la enseñanza y la práctica de las ciencias biomédicas. Materiales y métodos: Se realizó una investigación colaborativa, de desarrollo tecnológico entre el Centro de Fabricación Asistida y Sostenible de la Universidad de Matanzas y la Universidad de Ciencias Médicas de Matanzas, entre septiembre de 2019 y julio de 2022. Los diseños y fabricaciones se realizaron a partir de la adquisición de imágenes de tomografía computarizada, o desde un escáner de superficie, las que luego se procesaron, se convirtieron en formato Standard Tessellation Language, se imprimieron y posprocesaron. Los diseños virtuales se desarrollaron empleando un software de diseño asistido por computadora. Resultados: Se desarrollaron varias soluciones que incluyen varios prototipos: biomodelos para reparación de craneosinostosis y figuras anatómicas, molde de prótesis craneal personalizada, prótesis de mano, divisores de líneas de O2, andamios tisulares, pistola portajeringas, protectores faciales, prótesis de mama, molde para restauración autóloga y expansor tisular. Conclusiones: En todas las áreas de aplicación de esta tecnología en medicina―salvo en la impresión de medicamentos, en el contexto actual―, es factible obtener soluciones en el territorio de Matanzas. Es un imperativo, pues, que directivos y la comunidad médica en general, comiencen a adquirir conciencia, conocimientos y experiencias para garantizar la utilización óptima de esta tecnología.

Research status and development of biodegradable zinc alloy as orthopedics implant / 生物医学工程学杂志

Znic (Zn) alloys with good cytocompatibility and suitable degradation rate have been a kind of biodegradable metal with great potential for clinical applications. This paper summarizes the biological role of degradable Zn alloy as bone implant materials, discusses the mechanical properties of different Zn alloys and their advantages and disadvantages as bone implant materials, and analyzes the influence of different processing strategies (such as alloying and additive manufacturing) on the mechanical properties of Zn alloys. This paper provides systematic design approaches for biodegradable Zn alloys as bone implant materials in terms of the material selection, product processing, structural topology optimization, and assesses their application prospects with a view to better serve the clinic.

Evaluation of EDM inclusion into the conventional polishing of printed Co-Cr alloy by selective laser melting / Avaliação da inclusão de EDM no polimento convencional da liga de Co-Cr impressa por fusão seletiva a laser

Objective: The selective laser melting (SLM) technique used in manufacturing results in a rougher surface that requires more satisfying processing than conventional hand-finishing operations. The electro discharge machine (EDM) has various possibilities in the adjustment of surfaces. The present study assesses whether the participation of the EDM technique with the conventional finishing and polishing methods enables surface improvement for the Cobalt-Chromium alloy fabricated by SLM. Material and Methods: Twenty discs of cobalt chromium alloy were fabricated by SLM, divided equally into two groups: (TF) control group for finishing and polishing in the conventional method in accordance with the manufacturer's recommendations; and (EF) group for conducting polishing incorporating the EDM method. Results: The EF group recorded the lowest mean value of surface roughness and the highest mean value of micro hardness compared to the TF group. Furthermore, statistically significant differences (P < 0.05) were found for surface roughness as well as micro hardness. Conclusion: Reliance of the electric discharge machine proactively within finishing and polishing procedures promotes competence in the conventional polishing method and improves the surface properties of cobalt chromium alloy printed by SLM technology (AU)

Objetivo: A técnica de fusão a laser seletiva (SLM) usada na fabricação resulta em uma superfície mais rugosa a qual requer um processamento mais satisfatório do que o acabamento manual. A máquina de eletro descarga (EDM) possui várias possibilidades no ajuste de superfícies. O presente estudo avalia se a participação da técnica EDM associada aos métodos convencionais de acabamento e polimento possibilita a melhora da superfície da liga Cobalto-Cromo fabricada através da SLM. Material e Métodos: Vinte discos de liga de cromo-cobalto foram confeccionados por SLM, e divididos igualmente em dois grupos: (TF) grupo controle, realizado acabamento e polimento pelo método convencional de acordo com as recomendações do fabricante; e (EF) grupo do polimento associado ao método EDM. Resultados: O grupo EF registrou o menor valor médio de rugosidade superficial e o maior valor médio de microdureza em relação ao grupo TF. Além disso, diferenças estatisticamente significativas (P < 0,05) foram encontradas para rugosidade superficial, assim como para a microdureza. Conclusão: A confiança na máquina de descarga elétrica proativamente nos procedimentos de acabamento e polimento promove a competência no método de polimento convencional e melhora as propriedades de superfície da liga de cromo-cobalto impressa pela tecnologia SLM(AU)

Aplicações da manufatura aditiva em oftalmologia / Applications of additive manufacturing in ophthalmology

RESUMO A manufatura aditiva, mais popularmente conhecida como impressão tridimensional, baseia-se no desenvolvimento de um objeto com a ajuda de um software de desenho assistido por computador seguido de sua impressão por meio da deposição de uma matéria-prima, camada por camada, para a construção do produto desejado. Existem vários tipos de técnicas de impressão tridimensional, e o tipo de processo de impressão escolhido depende da aplicação específica do objeto a ser desenvolvido, dos materiais a serem utilizados e da resolução necessária à impressão do produto final. A impressão tridimensional abriu perspectivas na pesquisa e revolucionou o campo das ciências da saúde, com a possibilidade de criação e de desenvolvimento de produtos personalizados de maneira rápida, econômica e de forma mais centralizada do que no processo de manufatura tradicional. As tecnologias de manufatura aditiva remodelaram os diagnósticos médicos; as medidas preventivas e pré-operatórias; o tratamento e a reabilitação, assim como os processos de engenharia de tecidos nos últimos anos. Na oftalmologia, as aplicações da impressão tridimensional são extensas. Modelos anatômicos para aplicação na área da educação e planejamentos cirúrgicos, desenvolvimento de implantes, lentes, equipamentos para diagnósticos, novas aplicações terapêuticas e desenvolvimento de tecidos oculares já estão em desenvolvimento. Por possuir um campo amplo e ser alvo de pesquisa constante, a área oftalmológica permite que a manufatura aditiva ainda seja amplamente utilizada a favor dos médicos e dos pacientes.

ABSTRACT Additive manufacturing, more popularly known as three-dimensional (3D) printing, is based on the development of an object with the help of computer-aided design software followed by its printing through the deposition of a material, layer by layer, to create the desired product. There are several types of 3D printing techniques and the type of printing process chosen depends on the specific application of the object to be developed, the materials to be used, and the resolution required to print the final product. 3D printing has brought new perspectives to research and revolutionized the field of health sciences, with the possibility of creating and developing customized products in a faster, more economical, and more centralized way than in the traditional manufacturing process. Additive manufacturing technologies have reformulated medical diagnostics, preventive, preoperative, treatment, and rehabilitation, as well as tissue engineering processes in recent years. In ophthalmology, the applications of 3D printing are extensive. Anatomical models for application in education and surgical planning, development of implants, lenses, diagnostic equipment, new therapeutic applications, and development of ocular tissues (3D bioprinting) are already under development. As it has a wide field and is the subject of constant research, the ophthalmic area allows additive manufacturing to still be widely used in favor of doctors and patients.

Application of microcarrier technology in cartilage repairing: a review / 生物工程学报

Cartilage has poor self-recovery because of its characteristics of no blood vessels and high extracellular matrix. In clinical treatment, physical therapy or drug therapy is usually used for mild cartilage defects, and surgical treatment is needed for severe ones. In recent years, cartilage tissue engineering technology provides a new way for the treatment of cartilage defects. Compared with the traditional surgical treatment, cartilage tissue engineering technology has the advantages of small wound and good recovery. The application of microcarrier technology in the design of tissue engineering scaffolds further expands the function of scaffolds and promotes cartilage regeneration. This review summarized the main preparation methods and development of microcarrier technology in recent years. Subsequently, the properties and specific application scenarios of microcarriers with different materials and functions were introduced according to the materials and functions of microcarriers used in cartilage repair. Based on our research on osteochondral integrated layered scaffolds, we proposed an idea of optimizing the performance of layered scaffolds through microcarriers, which is expected to prepare bionic scaffolds that are more suitable for the structural characteristics of natural cartilage.

Finite Element Analysis on Treatment Effect of Additive Manufacturing Scoliosis Orthosis / 医用生物力学

Objective To evaluate the efficacy of additive manufacturing scoliosis orthosis, by simulation on interaction of the bone, trunk and orthosis using finite element method. Methods Combined with CT data of the patients, three-dimensional (3D) scanning model of the trunk and full length X-ray of the spine, the bone-trunk-orthosis finite element model was established and proved to be effective. The change and development trend of Cobb angle of the main thoracic scoliosis was calculated under different boundary and load conditions. Results The treatment effect of the additive manufacturing scoliosis orthosis was good. With the increase of orthotic preload, the improvement of Cobb angle and pelvic tilt was more obvious. The Cobb angle was expected to decrease by 6.18° after application of 70 N preload to the orthosis for 6 months. In the case of increasing system stiffness, Cobb angle improvement was not obvious and became even worse. Conclusions Additive manufacturing scoliosis orthosis is effective for treating adolescents with immature bones, while for patients with mature or degenerative bones, its treatment effect is poor.

Three-dimensional digitalized and printed tongue models of the cow, dog, pig, and horse for undergraduate veterinary educationh / Modelos tridimensionales digitalizados e impresos de lengua de vaca, perro, cerdo y caballo para la educación veterinaria de pregrado

SUMMARY: This study aimed to construct three-dimensional (3D) anatomical models of the tongue of domestic mammals of veterinary interest. The tongues were obtained from the didactic collection of the Laboratory of Veterinary Macroscopic Anatomy in the Surgery Department of the School of Veterinary Medicine and Animal Science, University of Sao Paulo. Tongues from a cow, dog, horse, and pig were selected for scanning and creation of the 3D-printed models. The printer used a filamentous thermoplastic material, acrylonitrile-butadiene-styrene (ABS), which was deposited together with a support resin. In addition to the printing of models, an interactive 3D PDF was generated, creating a didactic collection for students. The anatomical characteristics and peculiarity of the tongues were easily identified in the scanned and printed images. The 3D scanning and printing offered an innovative method of visualizing different anatomical structures and, together with the existing methods, can optimize anatomy teaching in an educational context.

RESUMEN: Este estudio tuvo como objetivo construir modelos anatómicos tridimensionales (3D) de la lengua de mamíferos domésticos de interés veterinario. Las lenguas se obtuvieron de la colección didáctica del Laboratorio de Anatomía Macroscópica Veterinaria del Departamento de Cirugía de la Facultad de Medicina Veterinaria y Zootecnia de la Universidad de São Paulo. Se seleccionaron lenguas de vaca, perro, caballo y cerdo para escanear y crear los modelos impresos en 3D. La impresora utilizó un material termoplástico filamentoso, acrilonitrilo-butadieno-estireno (ABS), que se depositó junto con una resina de soporte. Además de la impresión de modelos, se generó un PDF 3D interactivo, creando una colección didáctica para los estudiantes. Las características anatómicas y la peculiaridad de las lenguas se identificaron fácilmente en las imágenes escaneadas e impresas. El escaneo e impresión 3D ofrecieron un método innovador para visualizar diferentes estructuras anatómicas y, junto con los métodos existentes, puede optimizar la enseñanza de la anatomía en un contexto educativo.

Current perspectives of 3d printing in dental applications / Perspectivas Atuais Da Impressão 3D Em Aplicações Odontológicas

Objective: To evaluate the applications of 3d printing /additive manufacturing (AM) in dental education & clinical dentistry and elaborate various 3d printing technologies, its benefits, limitations and future scope. Methods: Research papers on the application of 3d printing in dentistry were searched in Scopus and Pubmed and studied using bibliometric analysis. This review briefly describes various types of 3d printing technologies with their accuracy, use of different materials for 3d printing and their respective dental applications. It also discusses various steps used to create 3D printed dental model using this technology. Furthermore, the application of this technology in dental education and various clinical procedures are discussed. Results: 3d printing is an innovative technology making a paradigm shift towards treatment customization. It helps in customized production of dental implants, surgical guides, anatomic models etc. using computer-aided design (CAD) data. This technology coupled with state-of-the-art imaging techniques and CAD software has enabled, especially oral surgeons to precisely plan and execute complex surgeries with relative ease, high accuracy and lesser time. 3d printing is also being utilized in other disciplines of dentistry to prepare aligners, crown and bridge, endodontic guides, periodontal surgery guides, surgical models for treatment planning and patient education. Alongside its possibilities have also been explored in preclinical skills in operative, endodontics etc (AU)

Objetivo: Avaliar as aplicações da impressão 3D/manufatura aditiva (AM) na educação odontológica e odontologia clínica, e elaborar várias tecnologias de impressão 3D, seus benefícios, limitações e escopo futuro. Métodos: Artigos de pesquisa sobre a aplicação da impressão 3D em odontologia foram pesquisados no Scopus e no Pubmed e estudados por meio de análise bibliométrica. Esta revisão descreve resumidamente vários tipos de tecnologias de impressão 3D a partir da sua precisão, uso de diferentes materiais para impressão 3D e suas respectivas aplicações odontológicas. Ele também discute várias etapas usadas para criar um modelo dentário 3D impresso usando essa tecnologia. Além disso, a aplicação desta tecnologia na educação odontológica e vários procedimentos clínicos são discutidos. Resultados:a impressão 3D é uma tecnologia inovadora que está mudando o paradigma em direção à personalização do tratamento. Ele ajuda na produção personalizada de implantes dentários, guias cirúrgicos, modelos anatômicos etc. usando dados de design auxiliado por computador (CAD). Essa tecnologia, combinada com técnicas de imagem de última geração e software CAD, permitiu, especialmente aos cirurgiões orais, planejar e executar cirurgias complexas com relativa facilidade, alta precisão e menor tempo. A impressão 3D também está sendo utilizada em outras disciplinas da odontologia para preparar alinhadores, coroas e pontes, guias endodônticos, guias de cirurgia periodontal, modelos cirúrgicos para planejamento de tratamento e educação do paciente. Ao lado de suas possibilidades também foram exploradas em habilidades pré-clínicas em cirurgia, endodontia etc (AU)

Opportunities and challenges of three-dimensional printing technology in pharmaceutical formulation development

Three-dimensional printing is a technology that prints the products layer-by-layer, in which materials are deposited according to the digital model designed by computer aided design (CAD) software. This technology has competitive advantages regarding product design complexity, product personalization, and on-demand manufacturing. The emergence of 3D technology provides innovative strategies and new ways to develop novel drug delivery systems. This review summarizes the application of 3D printing technologies in the pharmaceutical field, with an emphasis on the advantages of 3D printing technologies for achieving rapid drug delivery, personalized drug delivery, compound drug delivery and customized drug delivery. In addition, this article illustrates the limitations and challenges of 3D printing technologies in the field of pharmaceutical formulation development.

Discussion on Technical Review Guidance for Registration of Personalized Additive Manufacturing Medical Devices of Passive Implantable Bone, Joint and Oral Hard Tissues / 中国医疗器械杂志

OBJECTIVE@#This paper introduces the key content and background of Technical Review Guidance for the Registration of Personalized Additive Manufacturing Medical Devices of Passive Implantable Bone, Joint and Oral Hard Tissues.@*METHODS@#The core contents and importance of the construction of personalized design validation and verification and additive manufacturing system are described respectively.@*RESULTS@#The personalized design needs to be carried out under the control of interactive cooperation between healthcare professional and engineer. And the performance of personalized device must be validated and verified completely. At the same time, in view of the particularity of the quality management system of additive manufacturing, the technical focus is expounded.@*CONCLUSIONS@#New ideas and methods shall be used in evaluate and administrate personalized additive manufacturing medical device.

Design of Monitorable Wrist Orthosis Based on 3D Printing / 中国医疗器械杂志

A 3D printing based wrist orthosis device was developed. After collecting the contour information of the carpal and metacarpophalangeal joints of the patients with a 3D scanner, the wrist orthotics were designed to meet the individual needs of the patients according to the relevant requirements of biomechanics. Choose TPU (thermoplastic polyurethanes) materials for preparation of 3D printing. It can functionally assist the smart brace after stroke patients with hemiplegia early rehabilitation training, the use of orthoses carry MPU6050 inertial sensor, magnetometer, time module device such as a sensor and monitor its movements and record the training time, ensure safe efficient rehabilitation training, help patients return to a normal life as soon as possible.

Marginal and internal discrepancy of 3-unit fixed dental prostheses fabricated by subtractive and additive manufacturing / 대한치과보철학회지

PURPOSE: This study was to evaluate marginal and internal discrepancy of 3-unit fixed dental prostheses (FDP) fabricated by subtractive manufacturing and additive manufacturing.MATERIALS AND METHODS: 3-unit bridge abutments without the maxillary left second premolar were prepared (reference model) and the reference model scan data was obtained using an intraoral scanner. 3-unit fixed dental prostheses were fabricated in the following three ways: Milled 3-unit FDP (MIL), digital light processing (DLP) 3D printed 3-unit FDP (D3P), stereolithography apparatus (SLA) 3D printed 3-unit FDP (S3P). To evaluate the marginal/internal discrepancy and precision of the prosthesis, scan data were superimposed by the triple-scan protocol and the combinations calculator, respectively. Quantitative and qualitative analysis was performed using root mean square (RMS) value and color difference map in 3D analysis program (Geomagic control X). Statistical analysis was performed using the Kruskal-Wallis test (α=.05), Mann-Whitney U test and Bonferroni correction (α=.05/3=.017).RESULTS: The marginal discrepancy of S3P group was superior to MIL and D3P groups, and MIL and D3P groups were similar. The D3P and S3P groups showed better internal discrepancy than the MIL group, and there was no significant difference between the D3P and S3P groups. The precision was excellent in the order of MIL, S3P, and D3P groups.CONCLUSION: Within the limitation of this study, the 3-unit fixed dental prostheses fabricated by additive manufacturing showed better marginal and internal discrepancy than the those of fabricated by subtractive manufacturing, but the precision was poor.

Application and progress of three-dimensional printing technology in hip arthroplasty / 中国组织工程研究

BACKGROUND: Three-dimensional (3D) printing technology is a new rapid prototyping technology, which has been initially applied in orthopedics, especially in the clinical application of hip replacement surgery. OBJECTIVE: To summarize the application status, existing problems and future development direction of 3D printing technology in hip arthroplasty. METHODS: The relevant articles published between January 2000 and March 2019 were retrieved from PubMed, CNKI and WanFang databases. The keywords were "3D printing, rapid prototyping, additive manufacturing, computer aided, computer-assisted, hip, hip replacement, hip arthroplasty, revision hip arthroplasty" in English and Chinese, respectively. Initially, 1 833 articles were retrieved, and finally 105 eligible articles were included for result analysis in accordance with the inclusion and exclusion criteria. RESULTS AND CONCLUSION: (1) In the clinical application of hip replacement surgery, 3D printing technology Is mainly used to make anatomical models for clinical teaching or preoperative plan, patient-specific surgical guides, customized implants or prostheses. (2) The advantages of 3D printing technology can make up for the deficiency of traditional treatment, and it can help to optimize the surgical plan, shorten the operation time, decrease the bleeding, reduce postoperative complications, improve the accuracy of surgery and clinical results. (3) Individualized treatment with 3D printing technology will become a new direction in hip arthroplasty.

Biomonitoring of Metal Exposure During Additive Manufacturing (3D Printing)

BACKGROUND: Additive manufacturing (AM) is a rapidly expanding new technology involving challenges to occupational health. Here, metal exposure in an AM facility with large-scale metallic component production was investigated during two consecutive years with preventive actions in between.METHODS: Gravimetric analyzes measured airborne particle concentrations, and filters were analyzed for metal content. In addition, concentrations of airborne particles <300 nm were investigated. Particles from recycled powder were characterized. Biomonitoring of urine and dermal contamination among AM operators, office personnel, and welders was performed.RESULTS: Total and inhalable dust levels were almost all below occupational exposure limits, but inductively coupled plasma mass spectrometry showed that AM operators had a significant increase in cobalt exposure compared with welders. Airborne particle concentrations (<300 nm) showed transient peaks in the AM facility but were lower than those of the welding facility. Particle characterization of recycled powder showed fragmentation and condensates enriched in volatile metals. Biomonitoring showed a nonsignificant increase in the level of metals in urine in AM operators. Dermal cobalt and a trend for increasing urine metals during Workweek Year 1, but not in Year 2, indicated reduced exposure after preventive actions.CONCLUSION: Gravimetric analyses showed low total and inhalable dust exposure in AM operators. However, transient emission of smaller particles constitutes exposure risks. Preventive actions implemented by the company reduced the workers' metal exposure despite unchanged emissions of particles, indicating a need for careful design and regulation of the AM environments. It also emphasizes the need for relevant exposure markers and biomonitoring of health risks.

In vitro evaluation of the wear resistance of provisional resin materials fabricated by different methods / 대한치과보철학회지

PURPOSE: This study was to evaluate the wear resistance of 3D printed, milled, and conventionally cured provisional resin materials. MATERIALS AND METHODS: Four types of resin materials made with different methods were examined: Stereolithography apparatus (SLA) 3D printed resin (S3P), digital light processing (DLP) 3D printed resin (D3P), milled resin (MIL), conventionally self-cured resin (CON). In the 3D printed resin specimens, the build orientation and layer thickness were set to 0° and 100 µm, respectively. The specimens were tested in a 2-axis chewing simulator with the steatite as the antagonist under thermocycling condition (5 kg, 30,000 cycles, 0.8 Hz, 5℃/55℃). Wear losses of the specimens were calculated using CAD software and scanning electron microscope (SEM) was used to investigate wear surface of the specimens. Statistical significance was determined using One-way ANOVA and Dunnett T3 analysis (α = .05). RESULTS: Wear losses of the S3P, D3P, and MIL groups significantly smaller than those of the CON group (P .05). In the SEM observations, in the S3P and D3P groups, vertical cracks were observed in the sliding direction of the antagonist. In the MIL group, there was an overall uniform wear surface, whereas in the CON group, a distinct wear track and numerous bubbles were observed. CONCLUSION: Within the limits of this study, provisional resin materials made with 3D printing show adequate wear resistance for applications in dentistry.

Additive manufacturing to veterinary practice: recovery of bony defects after the osteosarcoma resection in canines

The paper outlines the achievements and challenges in the additive manufacturing (AM) application to veterinary practice. The state-of-the-art in AM application to the veterinary surgery is presented, with the focus of AM for patient-specifi c implants manufacturing. It also provides critical discussion on some of the potential issues design and technology should overcome for wider and more eff ective implementation of additively manufactured parts in veterinary practices. Most of the discussions in present paper are related to the metallic implants, manufactured in this case using so-called powder bed additive manufacturing (PB-AM) in titanium alloy Ti–6AL–4V, and to the corresponding process of their design, manufacturing and implementation in veterinary surgery. Procedures of the implant design and individualization for veterinary surgery are illustrated basing on the four performed surgery cases with dog patients. Results of the replacement surgery in dogs indicate that individualized additively manufactured metallic implants signifi cantly increase chances for successful recovery process, and AM techniques present a viable alternative to amputation in a large number of veterinary cases. The same time overcoming challenges of implant individualization in veterinary practice signifi cantly contributes to the knowledge directly relevant to the modern medical practice. An experience from veterinary cases where organ-preserving surgery with 3D-printed patient-specifi c implants is performed provides a unique opportunity for future development of better human implants.

Fabrication of additive manufacturing interim denture and comparison with conventional interim denture: A case report / 대한치과보철학회지

With development of digital dentistry, the 3-dimensional (3D) manufacturing industry using computer-aided design and computer-aided manufacturing (CAD/CAM) has grown dramatically in recent years. Denture fabrication using digital method is also increasing due to the recent development of digital technology in dentistry. The 3D manufacturing process can be categorized into 2 types: subtractive manufacturing (SM) and additive manufacturing (AM). SM, such as milling is based on cutting away from a solid block of materal. AM, such as 3D printing, is based on adding the material layer by layer. AM enables the fabrication of complex structures that are difficult to mill. In this case, additive manufacturing method was applied to the fabrication of the resin-based complete denture to a 80 year-old patient. During the follow-up periods, the denture using digital method has provided satisfactory results esthetically and functionally.

Comparison analysis of fracture load and flexural strength of provisional restorative resins fabricated by different methods / 대한치과보철학회지

PURPOSE: This study was undertaken to compare fracture and flexural strength of provisional restorative resins fabricated by additive manufacturing, subtractive manufacturing, and conventional direct technique. MATERIALS AND METHODS: Five types of provisional restorative resin made with different methods were investigated: Stereolithography apparatus (SLA) 3D printer (S3Z), two digital light processing (DLP) 3D printer (D3Z, D3P), milling method (MIL), conventional method (CON). For fracture strength test, premolar shaped specimens were prepared by each method and stored in distilled water at 37℃ for 24 hours. Compressive load was measured using a universal testing machine (UTM). For flexural strength test, rectangular bar specimens (25 × 2 × 2 mm) were prepared by each method according to ISO 10477 and flexural strength was measured by UTM. RESULTS: Fracture strengths of the S3Z, D3Z, and D3P groups fabricated by additive manufacturing were not significantly different from those of MIL and CON groups (P>.05/10=.005). On the other hand, the flexural strengths of S3Z, D3P, and MIL groups were significantly higher than that of CON group (P<.05), but the flexural strength of D3Z group was significantly lower than that of CON group (P<.05). CONCLUSION: Within the limitation of our study, provisional restorative resins made from additive manufacturing showed clinically comparable fracture and flexural strength as those made by subtractive manufacturing and conventional method.

Insights Into Emissions and Exposures From Use of Industrial-Scale Additive Manufacturing Machines

BACKGROUND: Emerging reports suggest the potential for adverse health effects from exposure to emissions from some additive manufacturing (AM) processes. There is a paucity of real-world data on emissions from AM machines in industrial workplaces and personal exposures among AM operators. METHODS: Airborne particle and organic chemical emissions and personal exposures were characterized using real-time and time-integrated sampling techniques in four manufacturing facilities using industrial-scale material extrusion and material jetting AM processes. RESULTS: Using a condensation nuclei counter, number-based particle emission rates (ERs) (number/min) from material extrusion AM machines ranged from 4.1×1010 (Ultem filament) to 2.2×1011 [acrylonitrile butadiene styrene and polycarbonate filaments). For these same machines, total volatile organic compound ERs (mg/min) ranged from 1.9×104 (acrylonitrile butadiene styrene and polycarbonate) to 9.4×104 (Ultem). For the material jetting machines, the number-based particle ER was higher when the lid was open (2.3×1010 number/min) than when the lid was closed (1.5–5.5×109 number/min); total volatile organic compound ERs were similar regardless of the lid position. Low levels of acetone, benzene, toluene, and m,p-xylene were common to both AM processes. Carbonyl compounds were detected; however, none were specifically attributed to the AM processes. Personal exposures to metals (aluminum and iron) and eight volatile organic compounds were all below National Institute for Occupational Safety and Health (NIOSH)-recommended exposure levels. CONCLUSION: Industrial-scale AM machines using thermoplastics and resins released particles and organic vapors into workplace air. More research is needed to understand factors influencing real-world industrial-scale AM process emissions and exposures.

Analysis On The Effect Of Personalised Insole For Prolonged Standing Industrial Workers

@#Working in prolonged standing position among industrial workers has been shown to be associated with different potentially serious health outcomes, namely lower back pain, leg pain, fatigue, discomfort, and other health issues. Personalisation of insole offers a solution that will provide a perfect fit and comfort to the shoes wearer based on the ergonomic considerations. It works in a way that it alters the pressure away from painful areas by increasing the surface area that supports the weight of the body and evenly distributes it to the whole plantar area. Survey was conducted among workers at a manufacturing industry company to study on the level of pain experienced by them together with their foot anthropometry. Then, the foot pressure of each of the workers was collected by using pressure measurement device (F-scan). Combination of these data was used to design the customized insole that is fit for the worker. The personalised insoles were fabricated by using Additive Manufacturing technology. After that, the insoles were validated by using the F-scan and Electromyogram (EMG) to ensure their effectiveness in reducing pressures on the foot and muscle activity hence improving the comfort of the shoe wearer. At the end of the experiment, it was found that the insole is able to reduce the peak pressure of four out of five areas of the worker’s foot with the reduction of pressure percentage ranging from 6% to 28%.