Three-dimensional Printing Research Articles

Fracture resistance of analog and CAD-CAM long-span fixed provisional restorations: An in vitro experimental study.

This study aimed to evaluate and compare the fracture resistance of long-span fixed provisional restorations fabricated using milling, three-dimensional (3D) printing, and conventional methods. Sixty specimens were prepared, divided into four groups of 15 each, corresponding to four fabrication methods: computer-aided design and computer-aided manufacturing (CAD-CAM) milled provisional resins, 3D-printed provisional resins, 3D-printed permanent resins, and conventional bis-acryl restorations reinforced with wire. The specimens underwent a three-point bending test using a universal testing machine to measure fracture resistance, quantified as maximum force (in Newtons). Statistical analysis was performed using one-way ANOVA and Tukey's HSD post-hoc tests to compare the fracture resistance across the four groups. Significant differences in fracture resistance were observed among the materials tested (p < 0.001). Both the CAD-CAM milled and 3D-printed resins exhibited significantly higher fracture resistance than the conventional bis-acryl method. The results highlight the mechanical advantages of digital fabrication methods for long-span provisional applications in prosthodontics. These techniques may provide improved durability and reliability, addressing the mechanical demands of complex restorations.

Self-healing behavior of metallopolymers in complex.

This current study focusses on the investigation of the self-healing abilities of metallopolymers containing different kinds of metal complexes, which were processed by direct digital light processing (DLP) based three-dimensional (3D) printing. For this purpose, 2‑phenoxyethyl acrylate is mixed with ligand-containing monomers either based on triphenylmethyl(trt)-histidine or terpyridine, respectively. Either zinc(II) or nickel(II) salts are successfully applied for a complexation of the ligand monomers in solution and, subsequently, photopolymerization is performed. The thermo-mechanical properties of the obtained metallopolymers were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) as well asdynamic mechanical thermal analysis (DMTA). Multiple damages with defined forces ranging from 20 to 1500 mN were introduced into the 3D-structures and successfully healed within 24h at 70°C or 120°C, respectively without losing the structural integrity of the overall 3D-structures. Herein, excellent healing efficiencies up to 97% were determined. Consequently, these hollow structures not only feature very good self-healing abilities but also excellent retention of the 3D-structure at and above the healing temperature.

Optimization of 3D Printing Nozzle Parameters and the Optimal Combination of 3D Printer Process Parameters for Engineering Plastics with High Melting Points and Large Thermal Expansion Coefficients

Three-dimensional printing is a transformative technology in the manufacturing industry which provides customization and cost-effectiveness for all walks of life due to its fast molding speed, high material utilization, and direct molding of arbitrary complex structural parts. This study aims to improve the molding accuracy of 3D printed polyether ether ketone (PEEK) samples by systematically studying key process parameters, including printing speed, layer thickness, nozzle temperature, and filling rate. The 3D printing nozzle has an important impact on the extrusion rate of the melt, and the fluid simulation of the nozzle was carried out to explore the variation characteristics of the melt flow rate in the nozzle and optimize the nozzle structure parameters. In order to effectively optimize the process, considering its inherent efficiency, robustness, and cost-effectiveness, the L9 orthogonal array experimental design scheme was used to analyze the effects of printing speed, layer thickness, nozzle temperature, and filling rate on the molding accuracy of the test sample, and the optimal combination of process parameters was optimized through the comprehensive weighted scoring method so as to improve the molding accuracy of the 3D printed PEEK sample; finally, the molding accuracy of the components printed using the Sermoon-M1 3D printer with the optimized nozzle structure was printed. The results show that the nozzle structure is optimal when the convergence angle is 120° and the aspect ratio is 2, and the outlet cross-section velocity is increased by 2.5% and 2.7%, respectively. The order of influence strength on the dimensional accuracy of the test sample is layer thickness &gt; filling rate &gt; nozzle temperature &gt; printing speed. The optimal combination of parameters is: a printing speed of 15 mm/s, a layer thickness of 0.1 mm, a nozzle temperature of 420 °C, and a filling rate of 50%. The insights derived from this study pave the way for predicting and implementing the selection of optimal process parameters in the production of 3D printed products, with important implications for the optimal molding accuracy of printed components.

Three-Dimensional (3D) Printing in Non-Industrial Spaces: A Summary of Emissions Evaluations in 11 School Settings.

Additive manufacturing or 3-dimensional (3D) printing is an emerging technology with increasing prevalence in non-industrial settings such as university and school settings. However, printers are often located in spaces not designed for this purpose. 3D-printer use in 11 university and K-12 schools was evaluated by identifying emissions using area air sampling for volatile organic compounds (VOCs) and particle counting instruments (PCIs) measuring ultrafine particulate (UFP) and evaluating controls to reduce potential exposure. Ventilation in printer locations was also characterized. VOCs and UFP were identified during 3D printing. Best-practice recommendations were provided to school health and safety staff to protect users, including workers and students. Recommendations included installing and implementing engineering controls, administrative controls, and personal protective equipment (PPE) to minimize exposure to 3D printer emissions. School health and safety staff can translate findings and recommendations for these 11 evaluations to identify 3D-printing areas on their campuses and use principles of industrial hygiene to protect workers and students and prevent the movement of emissions. VOCs and UFP were detected during 3D printing. There were opportunities to improve health and safety practices and reduce potential exposure when using 3D printing technologies.

A study on the compressive strength of three-dimensional direct printing aligner material for specific designing of clear aligners

BackgroundThe demand for orthodontic treatment using clear aligners has been gradually increasing because of their superior esthetics compared with conventional fixed orthodontic therapy. This study aimed to evaluate and compare the compressive strength of three-dimensional direct printing aligners (3DPA) with that of conventional thermo-forming aligners (TFA) to determine their clinical applicability. In the experimental group, the 3DPA material TC-85 (TC-85 full) was used to create angular protrusions called rectangular pressure areas (RPA). A protrusion akin to the power ridge typically employed in conventional TFAs was created using glycol-modified polyethylene terephthalate (PETG; Control 1). RPA was created using the same TC-85 without filling the protrusions (TC-85 blank; Control 2). Compression cycle tests were conducted on an LTM 3 h electrodynamic testing machine (Zwick Roell, Germany), with 500 cycles and compression depths of 100, 300, 500, and 700 µm. Twenty specimens were tested for PETG, 17 for the TC-85 blank, and 19 for the TC-85 full.ResultsChanges in the compressive force were assessed based on the material and thickness. The results indicated significantly higher and broader ranges of compressive strength for specimens fabricated with the 3DPA material TC-85 compared with those fabricated using PETG. Among the TC-85 specimens, TC-85 full demonstrated the highest statistically significant compressive strength .Conclusions3DPA technology enables precise modifications in the shape and inner thickness at specific dental sites, including the creation of ridges in targeted areas, of aligners. These alterations enhance the biomechanical capability of aligners to exert selective forces necessary for desired tooth movement while reducing the number of attachments, thereby demonstrating the clinical potential of 3D-printed aligners in orthodontic treatment.

Three-Dimensional (3D) Printing in Surgical Pathology: The Design of a Novel Grossing Tool to Aid Staple Removal in Pulmonary Pathology Excision Specimens

Three-Dimensional (3D) Printing in Surgical Pathology: The Design of a Novel Grossing Tool to Aid Staple Removal in Pulmonary Pathology Excision Specimens

Applications, Design Methods, and Challenges for Additive Manufacturing of Thermal Solutions for Heterogeneous Integration of Electronics

Abstract Heterogeneous integration of electronics is critical to the next wave of electronics applications ranging from extremely power dense energy conversion systems to advanced chiplet and co-packaged optics architectures for next-generation computing. Enhanced functionality and operation are essential goals in heterogeneous integration. In all applications, effective thermal management of both active and passive electronic devices is required to support these goals. Additive manufacturing opens new avenues for heterogeneous integration of electronics. This article thus provides a review of additive manufacturing methods and applications in the specific context of thermal solutions for heterogeneous integration of electronics. Three-dimensional printing methods, associated materials (e.g., metal, polymer, ceramic, and composite), and electronics package integration approaches, or conceptual fabrication workflows, are outlined for cold plates, heat sinks, fluid flow manifolds, and thermal interface materials plus composites for electronics. The current status of design optimization methods for additive manufacturing of thermal solutions for electronics is also covered. Future challenges and research directions are outlined to further stimulate the development of advanced manufacturing methods, novel design techniques, and unique electronics package integration capabilities for thermal solutions.

Enhancing perioperative planning: three-dimensional printing templating in orthopaedic surgery

&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;Aim&amp;lt;/strong&amp;gt; 3D printing technology revolutionises orthopaedic surgery by creating accurate patient-specific models, surgical guides, and implants. The COVID-19 pandemic accelerated this trend, allowing localized solutions and biocompatible materials to replicate bone geometric complexity, enabling surgeons to plan and rehearse surgeries. This study aims to illustrate the use of 3D printing in the preoperative planning of a complex distal femur fracture.&amp;lt;br /&amp;gt;&amp;lt;strong&amp;gt;Methods&amp;lt;/strong&amp;gt; A 42-year-old woman with a complicated Gustilo-Anderson grade III-A fracture underwent 3D printing for implant planning, contouring, and screw trajectory visualization. The procedure took seven hours, and the surgery lasted only two hours, with no complications or complaints during a one-month follow-up.&amp;lt;br /&amp;gt;&amp;lt;strong&amp;gt;Results&amp;lt;/strong&amp;gt; 3D printing has revolutionized orthopaedic surgery by better visualizing complex fractures, reducing surgical time, and enhancing precision. Traditional 2D imaging techniques struggle to capture intricate details, requiring 3D printing for accurate preoperative planning and implant selection. However, challenges include high costs, time, and specialized training. Further research is needed to understand long-term outcomes.&amp;lt;br /&amp;gt;&amp;lt;strong&amp;gt;Conclusion&amp;lt;/strong&amp;gt; The benefits of 3D printing in orthopaedic surgery, including improved visualization, reduced time, and improved precision, highlight its potential for further advancement.&amp;lt;/p&amp;gt;

Perspectives of Additive Manufacturing in 5.0 Industry.

Additive manufacturing is a technology that creates objects by adding successive layers of material. The 3D method is an alternative to subtractive production, in which production involves removing material from the initial solid. 3D printing requires the initial design of the manufactured object using computer design, for example, one of the following programs: CAD, 3DCrafter, Wings 3D, Cinema 3, Blender, 3ds Max, Autodesk Inventor, and others. It is also possible to scan an existing object to be manufactured using 3D printing technology. An important element of Industry 5.0 is 3D printing technology, due to its favorable environmental orientation and production flexibility. Three-dimensional printing technology uses recycled materials such as powders. Therefore, it can be part of a circular economy, contributing to environmental protection. Additive manufacturing not only complements existing technologies by enabling rapid prototyping but also plays a fundamental role in sectors such as dentistry and medicine. This article consists of seven chapters relating to various aspects of 3D printing technology in the context of the assumptions and challenges of Industry 5.0. It examines the environmental impact and recycling potential of 3D printing technology, illustrates the economic integration of this technology within various industries, and discusses its future development prospects.

Clinical Efficacy of Three-Dimensional-Printed Pure Titanium Fracture Plates with Locking Screw Systems in Distal Tibia Fractures.

Background and Objectives: Distal tibia fractures are high-energy injuries characterized by a mismatch between standard plate designs and the patient's specific anatomical bone structure, which can lead to severe soft tissue damage. Recent advancements have focused on the development of customized metal plates using three-dimensional (3D) printing technology. However, 3D-printed metal plates using titanium alloys have not incorporated a locking system due to the brittleness of these alloys. Therefore, this study aimed to determine whether a locking mechanism can be effectively implemented using 3D-printed pure titanium and further evaluate the clinical outcomes of such implants in patients with distal tibia fractures. Materials and Methods: Between March 2021 and June 2022, nine patients who underwent open reduction and internal fixation for distal tibia fractures using 3D-printed pure titanium plates were enrolled. Pure titanium powder (Ti Gr.2, Type A, 3D Systems, USA) was spread to a thickness of 30 μm and partially sintered using a 500 W laser to produce the 3D-printed metal plates. The locking screws were fabricated using a milling process. Open reduction and internal fixation were performed on the nine patients using 10 customized plates. The clinical efficacy was analyzed using the union rate, and complications, such as infection and skin irritation, were evaluated to ensure a comprehensive outcome assessment. Results: Surgical treatment was successfully performed on nine patients, with nine of ten plates remaining stable and undamaged. However, one patient with neurofibromatosis experienced a fractured metal plate, which necessitated revision surgery using a metal rod. No screw loosening or surgical wound complications occurred. Conclusions: This study showed that 3D-printed pure titanium plates with integrated locking screw systems provide a viable and effective solution for managing distal tibia fractures. Three-dimensional printing and pure titanium show promise for orthopedic advancements.

The present status of research and related applications of three-dimensional printing in the field of healthcare.

As a new manufacturing technology, 3D printing technology has shown great potential in healthcare. The current study attempts to provide a comprehensive review of the current research landscape regarding the utilization of 3D printing technology in the healthcare sector. Nowadays, three-dimensional printing is applied in tissue engineering to manufacture complex and functionalized tissue scaffolds, hence providing strong support for regenerative medicine and enabling more precise tissue replacement in vivo. In the context of the manufacturing of medical models, the technology can reproduce with great accuracy the diseased organs or structures in question by the patient; in this respect, even bones are included. That gives intuitive physical models for surgical planning, simulation training, thereby improving the success rate of surgery and reducing complications. In the context of bespoke medical devices, 3D printing facilitates personalization of medical devices, such as prosthetics and implants, to a greater degree of fit for individual patient requirements. In the pharmaceutical sector, 3D printing technology is being employed to develop personalised medicines, with the objective of optimising drug release profiles in innovative ways. However, the application of 3D printing in healthcare also encounters obstacles, including the necessity to enhance the biocompatibility of the materials, achieve greater precision in printing, and establish more comprehensive standards and regulations. Nevertheless, the rapid development and wide spread of the use of 3D printing in health cannot be ruled out; more so, it is likely to change the face of healthcare in times to come

Narrative Review and Guide: State of the Art and Emerging Opportunities of Bioprinting in Tissue Regeneration and Medical Instrumentation.

Three-dimensional printing was introduced in the 1980s, though bioprinting started developing a few years later. Today, 3D bioprinting is making inroads in medical fields, including the production of biomedical supplies intended for internal use, such as biodegradable staples. Medical bioprinting enables versatility and flexibility on demand and is able to modify and individualize production using several established printing methods. A great selection of biomaterials and bioinks is available, including natural, synthetic, and mixed options; they are biocompatible and non-toxic. Many bioinks are biodegradable and they accommodate cells so upon implantation, they integrate within the new environment. Bioprinting is suitable for printing tissues using living or viable components, such as collagen scaffolding, cartilage components, and cells, and also for printing parts of structures, such as teeth, using artificial man-made materials that will become embedded in vivo. Bioprinting is an integral part of tissue engineering and regenerative medicine. The addition of newly developed smart biomaterials capable of incorporating dynamic changes in shape depending on the nature of stimuli led to the addition of the fourth dimension of time in the form of changing shape to the three static dimensions. Four-dimensional bioprinting is already making significant inroads in tissue engineering and regenerative medicine, including new ways to create dynamic tissues. Its future lies in constructing partial or whole organ generation.

Validation of mixed reality in planning orbital reconstruction with patient-specific implants

This study aims to evaluate and compare the usability and performance of mixed reality (MR) technology versus conventional methods for preoperative planning of patient-specific reconstruction plates for orbital fractures. A crossover study design was used to compare MR technology with conventional three-dimensional (3D) printing approaches in the planning of maxillofacial traumatology treatments. The primary focus was on user-friendliness and the accuracy of patient-specific reconstruction planning. Secondary outcomes included investigating time differences between the two approaches and evaluating the potential effects on the learning curve. Participants were asked to complete questionnaires assessing various aspects, such as visualization, interaction, segmentation, treatment planning, and evaluation. Objective endpoints were evaluated blindly, while subjective endpoints were analyzed through a double-blind process. The total workflow time for MR technology was significantly shorter compared to the conventional method. Moreover, treatment planning using MR was significantly more accurate (p = .028), with participants reporting a higher mean global satisfaction score compared to the conventional group (80.6% vs. 72.5%). This study sheds light on the potential benefits of employing MR technology in maxillofacial orbital reconstruction. This preoperative method allows for faster and more precise design of patient-specific implants for orbital reconstruction, potentially leading to improved long-term cost-effectiveness.

Current Concepts and Clinical Applications in Cartilage Tissue Engineering.

Cartilage injuries are extremely common in the general population, and conventional interventions have failed to produce optimal results. Tissue engineering (TE) technology has been developed to produce neocartilage for use in a variety of cartilage-related conditions. However, progress in the field of cartilage TE has historically been difficult due to the high functional demand and avascular nature of the tissue. Recent advancements in cell sourcing, biostimulation, and scaffold technology have revolutionized the field and made the clinical application of this technology a reality. Cartilage engineering technology will continue to expand its horizons to fully integrate three-dimensional printing, gene editing, and optimal cell sourcing in the future. This review focuses on the recent advancements in the field of cartilage TE and the landscape of clinical treatments for a variety of cartilage-related conditions.

Method for calculating the effective dielectric constant of a material with periodically distributed inhomogeneities

The article proposes a method for calculating the effective permittivity of a material with periodically distributed inhomogeneities. The method is based on the calculation of the equivalent electrical circuit of a unit cell of the material. To conduct experimental studies using three-dimensional DLP printing, samples of material with cylindrical air cavities of various diameters were manufactured. Comparison of the results of calculation and measurement of the effective dielectric constant showed a small divergence (up to 5%).

Reversible Thixotropic Rheological Properties of Graphene-Incorporated Epoxy Inks for Self-Standing 3D Printing.

As three-dimensional (3D) printing has emerged as a new manufacturing technology, the demand for high-performance 3D printable materials has increased to ensure broad applicability in various load-bearing structures. In particular, the thixotropic properties of materials, which allow them to flow under applied external forces but resist flowing otherwise, have been reported to enable rapid and high-resolution printing owing to their self-standing and easily processable characteristics. In this context, graphene nanosheets exhibit unique π-π stacking interactions between neighboring sheets, likely imparting self-standing capability to low-viscosity inks. Herein, we develop a thermally curable graphene-incorporated epoxy ink system that exhibits shear-thinning characteristics and upright standing capability owing to its high static yield stress (∼1,680 Pa). The reversible liquid-to-solid phase transition of the composite ink, absent in the pristine epoxy ink, is clearly identified by its viscoelastic properties and dynamic yield stress. This thixotropic composite ink enables the continuous filament printing of 10 stacked layers without the spreading of injected filaments. Significantly, the 3D-printed composite structure, post-thermal curing, exhibits robust structural integrity and is free from weld lines or voids at the stacked interfaces. Combined with the clearly elucidated processing-structure-property relationships of the ink system, our results highlight its potential for a wide spectrum of applications.

Three-Dimensional Printing of Polymer Composites: Manufacturing and Mechanics

Polymers have been heavily used in manufacturing for decades, and with their use, improvements in the desired materials via composite materials utilizing a polymer matrix have been commonplace. Naturally, the increase in polymer additive manufacturing has come with an increase in interest in additively manufacturing polymer composites. This paper primarily covers the fused deposition modeling (FDM) method, ultraviolet (UV)-cured resin methods, multiple resin printing, and embedded sensors associated with additive manufacturing. In particular, the manufacturing and subsequent effect on material properties compared to unreinforced and unmodified 3D-printed polymers, the tradeoffs required in doing so, and the mechanisms behind these effects are discussed. The manufacturing methodology used or developed and the mechanisms behind these selections are discussed along with insights that could be gathered from material property effects seen across different studies. The mechanisms discussed also focus on the mechanisms between the different materials comprising the composite produced.

AN OVERVIEW OF 3D PRINTING TECHNOLOGIES FOCUSING MULTIDRUG-LOADED 3D PRINTED DOSAGE FORMS

Objective: This review focuses on multidrug-loaded dosage forms produced with three-dimensional printing (3DP) technologies since the confirmation of Spritam®, the first 3D printed dosage form, in 2015. Result and Discussion: The integration of multiple drugs within a single dosage form through 3DP offers substantial flexibility in design, allowing for the customization of dosage, drug release profiles, and geometric structures. These formulations offer significant design flexibility by combining different drugs in a single unit, and have the potential to optimize treatment strategies, especially for diseases requiring multiple drug use. The wide literature search reveals that the most commonly used method is Fused Deposition Modeling (FDM) to obtain 3D printed dosage forms with various geometries, such as multi-compartment capsules or tablets, bi-layered or multi-layered tablets exhibiting different release kinetics, and core/shell structured tablets. Multidrug-loaded 3D-printed dosage forms have significant potential for individualizing fixed-dose combinations and have become a promising tool for advancing personalized medicine and improving therapeutic outcomes for polypharmacy. This innovative approach can optimize therapeutic efficacy, reduce side effects, and improve patient compliance. As research continues to expand, these formulations represent a promising direction for the future of drug development and treatment strategies.

Three-Dimensional Planning for Vascularized Bone Grafts: Implementation and Surgical Application for Complex Bone Reconstruction in the Hand and Forearm.

Background/Objectives: Vascularized bone grafts have been successfully established for complex bone defects. The integration of three-dimensional (3D) simulation and printing technology may aid in more precise surgical planning and intraoperative bone shaping. The purpose of the present study was to describe the implementation and surgical application of this innovative technology for bone reconstruction. Methods: This prospective pilot study was conducted between June 2019 and June 2024. For this evaluation, patients who received vascularized bone reconstruction assisted with 3D technology were included. For reconstruction, the free medial femoral condyle (MFC) flap was used as the vascularized bone graft. Patient-specific 3D-printed templates, based on individual 3D simulations according to defect characteristics, were used for surgical planning, including flap elevation, shaping and inset. Results: A total of six patients (five male) with an average age of 39 years (range 19-62 years) and a mean follow-up time of 15 months (range 5-24 months) were analysed. The indications were as follows: avascular necrosis of the carpal bones, a metacarpal defect after tumor resection and pseudoarthrosis after a fractured ulna. Three patients received an osteochondral and three patients received a cortico-cancellous MFC flap. Conclusions: Our evaluation of clinical application revealed enhanced preoperative planning as well as intraoperative performance. Although the implementation for this technology is challenging, the new insights gained in planning and surgical guidance have led us to incorporate this technology into our standard routine.

'Ship-in-a-Bottle' Integration of pH-Sensitive 3D Proteinaceous Meshes into Microfluidic Channels.

Microfluidic sensors incorporated onto chips allow sensor miniaturization and high-throughput analyses for point-of-care or non-clinical analytical tools. Three-dimensional (3D) printing based on femtosecond laser direct writing (fs-LDW) is useful for creating 3D microstructures with high spatial resolution because the structures are printed in 3D space along a designated laser light path. High-performance biochips can be fabricated using the 'ship-in-a-bottle' integration technique, in which functional microcomponents or biomimetic structures are embedded inside closed microchannels using fs-LDW. Solutions containing protein biomacromolecules as a precursor can be used to fabricate microstructures that retain their native protein functions. Here, we demonstrate the ship-in-a-bottle integration of pure 3D proteinaceous microstructures that exhibit pH sensitivity. We fabricated proteinaceous mesh structures with gap sizes of 10 and 5 μm. The sizes of these gaps changed when exposed to physiological buffers ranging from pH of 4 to 10. The size of the gaps in the mesh can be shrunk and expanded repeatedly by changing the pH of the surrounding buffer. Fs-LDW enables the construction of microscopic proteinaceous meshes that exhibit dynamic functions such as pH sensing and might find applications for filtering particles in microfluidic channels.