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Additive manufacturing has developed rapidly in recent years and has many useful applications in the clinical field. In particular, cranio-maxillo-facial (CMF) surgery requires high precision, which can be obtained with 3D printed patient-specific surgical guides and anatomical models. Among the many different printing options, selective laser sintering (SLS) seems to be rarely used in point-of-care applications, considering its apparent characteristics.This article examines the advantages and disadvantages of SLS printers for CMF point-of-care (PoC) by reviewing the literature and comparing in-house printed SLS and stereolithography (SLA) prints.The investigation showed that the easily sterilizable and robust materials processed by SLS printing are well suited for CMF surgical guides and have clear advantages over SLA parts.Some barriers to the use of SLS printers in PoC are likely to be the slightly higher complexity and cost.However, these will decrease as 3D printing technology advances and surgeon acceptance increases, making SLS a practical PoC tool.

3D bioprinting is a tissue engineering approach using additive manufacturing to fabricate tissue equivalents for regenerative medicine or medical drug testing. For this purpose, biomaterials that provide the essential microenvironment to support the viability of cells integrated directly or seeded after printing are processed into three-dimensional (3D) structures. Compared to extrusion-based 3D printing, which is most commonly used in bioprinting, stereolithography (SLA) offers a higher printing resolution and faster processing speeds with a wide range of cell-friendly materials such as gelatin- or collagen-based hydrogels and SLA is, therefore, well suited to generate 3D tissue constructs.While there have been numerous publications of conversions and upgrades for extrusion-based printers, this is not the case for state-of-the-art SLA technology in bioprinting. The high cost of proprietary printers severely limits teaching and research in SLA bioprinting. With mSLAb, we present a low-cost and open-source high-resolution 3D bioprinter based on masked SLA (mSLA). mSLAb is based on an entry-level (€350) desktop mSLA printer (Phrozen Sonic Mini 4 K), equipped with temperature control and humidification of the printing chamber to enable the processing of cell-friendly hydrogels. Additionally, the build platform was redesigned for easy sample handling and microscopic analysis of the printed constructs. All modifications were done with off-the-shelf hardware and in-house designed 3D printed components, printed with the same printer that was being modified.We validated the system by printing macroscopic porous scaffolds as well as hollow channels from gelatin-based hydrogels as representative structures needed in tissue engineering.

Three-dimensional (3D) printing technology has advanced for applications in the field of reconstructive surgery. This study reports the application of a comprehensive methodology to obtain an anatomical model, using computed tomography and 3D printing, to treat a patient with cancer who designed a prototype oculopalpebral prosthesis for the reconstruction of the affected area of the face (left eye). A personalized prototype was obtained, which adapted to the face of the person, and improved the aesthetics and quality of life. The applied techniques helped to make definitive prostheses using materials that could be permanent. The training and tests carried out in this study favored the understanding and assimilation of the technology and the possibility of applying it to patients in need of facial prosthetic rehabilitation.

The control of tritium (3H) in liquid-based tritium breeding blankets (TBBs) is one of the key points to assure their correct performance to prove the 3H sufficiency. For that, electrochemical sensors are a good option for tritium quantification since they can perform in-situ and online measurements.One of the multiple challenges for hydrogen detection is to find suitable materials that can operate at high temperatures and in harsh environments. In this context, perovskite-type ceramics, such as BaCe0.6Zr0.3Y0.1O3-α (BCZY), have elevated proton conductivity and exceptional stability even in reducing atmospheres and at elevated temperatures, which make them strong contenders for high-temperature hydrogen sensing applications.In the present study, we describe the development of a dual-mode hydrogen sensors based on 3D-printed BCZY, which allows a high degree of design flexibility. Crucible geometries were tested and characterized using X-ray diffraction and scanning electron microscopy. Electrochemical sensors were constructed and characterized at 400, 450 and 500 °C in both, amperometric and potentiometric configuration. The results demonstrated the capability of 3D-printed BCZY sensors for hydrogen detection in fusion reactors, offering a breakthrough solution for monitoring fusion processes.

Actuators are largely used in biomedical applications in the presence of sensitive live cells or biomolecules, which makes actuators triggered by water uptake highly appealing. Dual-material printing and hydration driven expansion is a method of choice to produce such actuators, but mostly rely of non-degradable polymers or on the combination of polymers of different nature that may lead to interface incompatibilities. To overcome this challenge, we report here on two photocrosslinkable resins based on a single family of degradable hydrophilic or hydrophobic star-shaped poly(ethylene glycol)-poly(lactide) copolymers. The two materials are first printed individually and characterized to ensure that their properties enable the printing of dual material objects by stereolithographic digital-light processing. Dual-materials actuators are then printed by sequential switching of the hydrophobic and hydrophilic resin baths. Objects of simple and complex shapes are easily obtained and exhibit rapid actuation (

In this work, we developed and analyzed a biphasic calcium phosphate (BCP) bioceramic for bone regeneration using stereolithography (SLA). The SLA method is a promising additive manufacturing (AM) technique capable of creating BCp parts with high accuracy and efficiency. However, the ceramic suspension used in SLA exhibits significantly higher viscosity and is not environmentally friendly. Therefore, adequate preparation of a suspension with low viscosity and high solid loading is essential. In this paper, we optimized the effects of surfactant doses and solid loading on the BCp slurry, and initially examined the process parameters of photocuring, debinding, and sintering. The utilization of 9 wt % Disperbyk (BYK) with a 40 vol % loading of BCp bioceramics exhibited a reasonably low viscosity of 8.9 mPa·s at a shear level of 46.5 s−1. Functional and structural analyses confirmed that BCp was retained after photocuring and subsequent treatment, which were incorporated into the BYK dispersion. The 3D printed objects with different sintered temperatures, specifically at 1100 °C, 1200 °C, and 1300 °C, were further optimized. Additionally, the surface roughness, porosity, and mechanical properties of BCp green parts were systematically investigated. Most importantly, in vitro analysis of cell attachment, differentiation, and red alizarin analysis could support the application of bone regeneration.

The Hilbert curve fractal pattern was used to create a self-filling structure with designed porosity that would be ideal for applications such as biomedical components, circuit boards, and building materials. 3-Dimensional Hilbert curve structures were designed and analysed by Finite Element Analysis for various functions in fluid transport, heat transfer, and structural applications. A bespoke glass/zirconia composite paste was optimised for the fabrication of these structures by ceramic stereolithography, achieving a thixotropic photosensitive paste with a high solid loading of 69 %. Optimisation of process parameters and sintering schedule was carried out to allow accurate fabrication of the composite glass/zirconia structures. 3-Dimensional Hilbert curve structures were successfully fabricated by stereolithography and the designed structures have potential uses as highly efficient components in various industries.

The prime focus of regenerative periodontal therapy is to reconstruct or regenerate the lost periodontium, including both hard and soft tissues. Over the years, periodontics has witnessed different regenerative modalities, such as bone grafts, guided tissue membranes, growth factors, stem cell technology, 3D printing, etc. 3D printing is a newly emerging manufacturing technology that finds applications in diverse fields, including aerospace, defense, art and design, medical and dental field. Originally developed for non-biological applications, 3D printing has undergone modifications to print biocompatible materials and living cells to minimize any potential compromise on cell viability. Thus, the utilisation of 3D printing in the regeneration of lost periodontal tissues represents a novel approach that facilitates optimal cell interactions and promotes the successful regeneration of biological tissues.

In this work, the SiC ceramics were fabricated by stereolithography (SLA) combined with reactive melt infiltration (RMI), and the microstructure and mechanical properties of SiC ceramics were optimized by adjusting the solid content and impregnating phenolic resin. The bulk density and bending strength of SiC ceramics were positively correlated with the proportion of SiC content. The SiC phase content was increased from 48.10% to 61.42% with the solid content increased from 30 vol% to 45 vol%. When the solid content was 40 vol%, the bulk density and bending strength of SiC ceramics attained the highest value of 2.85 g/cm3 and 234.8 MPa. Meanwhile, the pyrolysis shrinkage of SiC ceramics along the non-additive direction and the additive direction was 4.83% and 1.21%, respectively. This research has successfully demonstrated the direct correlation of microstructure and content of SiC with the performance parameters of SiC ceramics fabricated by SLA.

Stereolithography additive manufacturing (SLAM) has exhibited great potential for fabricating advanced ceramic objects with geometrically complicated structures for use in diverse fields owing to its excellent feature resolution and high surface quality. However, it is difficult to fabricate advanced ceramic parts with desired performance for structural and functional applications using this technology, because numerous binders used in ceramic SLAM must be removed by thermal debinding (TD), resulting in various defects generation and long processing period. In this review, we first focus on the raw materials used to create photocurable ceramic suspensions that greatly affect the TD process. We then highlight three important issues related to the TD process: TD mechanism, characterization method, and TD procedure design. Besides, this review summarizes the basis and principles for designing reasonable TD profiles for various practical applications. Finally, this review presents the challenges and future perspective for TD of ceramic SLAM. This review provides an overview of the crucial TD process for advanced ceramic components fabricated using SLAM approach, thus providing valuable reference information and helping readers grasp the theoretical foundation for the targeted design of TD schemes to stimulate the development of advanced ceramic parts manufactured by SLAM in both academia and industry.

Additive manufacturing of bio-ceramics using LCD stereolithography allows the creation of ceramic parts with unprecedented resolution for various medical applications. However, the potential of this technology can only be fully harnessed if the manufacturability of critical geometries is accurately characterized. Thus, this contribution provides a guide with examples for the characterization and analysis of the printability of β-tricalcium phosphate-filled resins using LCD stereolithography. Characterized features include the minimum bore diameter, the minimum wall thickness of free-standing walls and cylindrical pins, the maximum unsupported bridging and overhang and the maximum abrupt thickness changes of cylindrical components. The analysis addresses limitations and factors affecting manufacturability of bio-ceramic-filled resins, and gives recommendations for design and processing parameters. In addition, TGA analysis is presented as a guide for the selection of suitable debinding and sintering schedules for an optimized microstructure and functionality.

Silicate bioceramics, including systems based on the simultaneous presence of wollastonite (CaSiO3) and diopside (CaMgSi2O6), are of great interest in bone tissue engineering applications, especially in form of variously shaped three-dimensional scaffolds, as determined by application of several additive manufacturing technologies. In this framework, silicone resins, properly modified with CaO- and MgO-based fillers and blended with photocurable acrylates, are attractive both as precursors and as feedstock for additive manufacturing technologies, including stereolithography. The use of powder fillers, however, may lead to issues with homogeneity or with printing resolution (owing to light scattering). The present paper aims at presenting the first results from a new concept of incorporation of CaO and MgO, relying on salts dispersed in emulsion within a photocurable silicone/acrylate blend. Direct firing at 1100 °C of printed scaffolds successfully produced wollastonite-diopside glass-ceramic scaffolds, with a very fine crystal distribution. The strength-to-density was tuned by operating either on the topology of scaffolds or on the firing atmosphere (passing from air to N2).

Three-dimensional (3D) printing or Additive Manufacturing (AM) technology is an innovative tool with great potential and diverse applications in various fields. As 3D printing has been burgeoning in recent times, a tremendous transformation can be envisaged in medical care, especially the manufacturing procedures leading to personalized medicine. Stereolithography (SLA), a vat-photopolymerization technique, that uses a laser beam, is known for its ability to fabricate complex 3D structures ranging from micron-size needles to life-size organs, because of its high resolution, precision, accuracy, and speed. This review presents a glimpse of varied 3D printing techniques, mainly expounding SLA in terms of the materials used, the orientation of printing, and the working mechanisms. The previous works that focused on developing pharmaceutical dosage forms, drug-eluting devices, and tissue scaffolds are presented in this paper, followed by the challenges associated with SLA from an industrial and regulatory perspective. Due to its excellent advantages, this technology could transform the conventional “one dose fits all” concept to bring digitalized patient-centric medication into reality.

The development of new nanocomposites with added functionalities for Additive Manufacturing (AM) requires of a deep understanding of the 3D distribution of the selected nano-additives within the polymeric matrix, in order to optimize their performance. For this, electron tomography (ET) is an outstanding analysis technique that requires the material to withstand the electron exposure needed for the acquisition of several tens of images, becoming challenging for beam-sensitive materials. In this work, we analyse the parameters involved in the successful analysis by low dose ET of nanocomposites based in acrylic resins for stereolithography (SLA). Needle-shape electron-transparent specimens have been fabricated by focused ion beam (FIB), minimizing surface damage due to the high energy Ga+ ions. Microscope settings for tuning the electron dose applied during the ET analysis of these nanoneedles are discussed. A phenomenological study of the effect of increasing the electron dose in the scanning transmission electron microscopy (STEM) analysis of the material has been carried out, showing that ET can be effectively performed at low electron doses. Two case studies are presented, to illustrate the relevance of these analyses in the development of nanocomposites with added functionalities. Our results have revealed the crucial role of the dose rate and of inaccuracies in the calculation of critical electron doses for the design of ET experiments.

In this work, a new indirect additive manufacturing technique to produce tungsten-copper composites (W-Cu) triply periodic minimal surface (TPMS) geometries by investment casting is proposed. The process consists in the combination of stereolithography (SLA) and molten copper casting to realize complex architectures (i.e., gyroids) and to control the volume fractions of W and Cu, tailoring the composite properties.SiO2-based tubular molds were produced by SLA to reproduce the negative of the object to be casted. The positive shape of the final object was obtained by filling the cavity of the SiO2 mold with a mixture of tungsten and corn starch (CS), which was used as space holder. After a pyrolysis stage at high temperature, the W porous structure was infiltrated by melted copper under vacuum. The leaching of the SiO2 mold using a basic solution allowed obtaining the final geometry. W-based particles of different diameter (i.e., d50 = 10, 22, and 150 µm) were used, and CS content was changed between 5 and 30 %vol. (with respect to W) to adjust the copper content in the composite. In all cases, produced samples retained the geometric properties of the CAD design.

This study explores the feasibility of bioactive glass scaffolds by using a stereolithographic technology (digital light processing-based vat photopolymerization) as fabrication method and the micro-tomographic reconstruction of an open-cell polymeric sponge as input virtual model to the printing system, in the attempt to replicate the trabecular architecture of cancellous bone. Additively-manufactured scaffolds were investigated from morphological (scanning electron microscopy), microstructural (X-ray diffraction), mechanical (compressive tests) and bioactive viewpoints (immersion studies in simulated body fluid (SBF)). Well-densified foam-like glass scaffolds were obtained after sintering, provided with suitable mechanical properties (compressive strength 21.9 ± 6.2 MPa, elastic modulus 4.8 ± 0.1 GPa, Weibull modulus 3.9) for bone-contact applications. The formation of a hydroxyapatite layer on scaffold struts after soaking in SBF also demonstrated the in vitro bioactivity of the printed structures.

The integration of multifunctional elements directly embedded in three-dimensional (3D) printed parts is the cutting-edge of additive manufacturing (AM) and it is crucial for enlarging as well as for strengthening AM role in industrial applications. Here, a straightforward and low-cost method that synergically combines stereolithography (SLA) and selective electroless metallization (EM) is presented for the fabrication of 3D parts characterized by complex shapes and end-use multifunctionalities (conductive, magnetic, mechanical properties). To this end, a novel photocurable composite based on acrylate resin loaded with nickel (Ni) particles is developed for high-resolution SLA-printing of features with self-catalytic properties for EM. Ni particles are loaded in the resin to trigger metal deposition avoiding time consuming and expensive laser-based surface activation. The effect of Ni content on SLA behavior as well as on the efficiency of EM process is studied. Metallized SLA cured samples show good electrical and magnetic properties as well as improved robustness with respect to their non-loaded counterparts. Then, selective metallization of 3D printed parts is successfully achieved by implementing a multi-material SLA-printing where loaded and non-loaded resins are properly interchanged with strong adhesion at the interface, thus offering a cost-effective approach for rapid prototyping of functional free-form features on 3D structures.

Mullite is a widely used refractory ceramic due to its good properties and high temperature stability. The necessity to obtain complex mullite architectures has encouraged the development of new AM techniques with improved resolution and surface finishing quality. In the present work, mullite-based scaffolds were obtained by stereolithography using a commercial silica resin and alumina nanoparticles following two routes: infiltration of printed porous silica parts with a colloidal alumina sol and printing of silica/alumina parts by developing a photocurable alumina resin that is mixed with the silica one. Post-processing of the obtained parts was carried out, including debinding and subsequent reaction sintering of the starting ceramic materials to give rise to mullite phase. All materials were characterised in terms of composition and microstructure, demonstrating that the second route results more effective to produce mullite structures in the final parts due to the higher alumina concentration and the larger reaction surface.

A new concept for the additive manufacturing of nickel-modified polymer-derived ceramics via vat-based photopolymerization is presented. A photoactive polysiloxane resin system modified by nickel nitrate via methacrylic acid complexation was developed and modified to facilitate vat-based photopolymerization. Through pyrolysis of the Ni-modified preceramic polymer at temperatures between 600 and 800 °C, amorphous SiOC components with well-dispersed Ni nanoparticles can be obtained. The modified polymer and the fabricated structures were characterized by photorheology, thermal analysis, scanning and transmission electron microscopy, optical coherence tomography, and powder X-ray diffraction. In addition, the effect of pyrolysis temperature on specific surface area, crystallinity, and shrinkage was investigated. The developed material systems enable additive manufacturing of porous SiOC structures containing crystalline, uniformly distributed, and bimodally sized Ni nanoparticles, exhibiting catalytic activity suitable for CO2 methanation. The developed printable SiOC/Ni materials represent a promising approach for combining metal-modified polymer-derived ceramic systems and additive manufacturing for prospective catalysis applications.

Mechanical metamaterials are generally two-dimensional periodic structures or three-dimensional cellular structures that exhibit mechanical properties beyond the ordinary. Due to size and boundary effects, three-dimensional mechanical metamaterials typically display anisotropic changes even if they are isotropic in construction and composition. However, in this study, the comprehensive design and fabrication of a three-dimensional axisymmetric auxetic structure that exhibits uniform and axisymmetric transverse deformation under longitudinal compression loading are proposed. Extending the concept of two-dimensional periodically perforated auxetic sheet structures to the third dimension, the design of the metamaterial was generated by revolving a two-dimensional parabolic curve along the axis of rotation and subsequently perforating the structure periodically with elliptical voids varying in size longitudinally along the curvature of the structure in order to promote the exhibition of isotropic negative Poisson's ratio. Furthermore, this study elucidates the significance of the perforations by comparing the metamaterial structure to a so-called plain structure.

This work presents W-band (75–110 GHz) dielectric characterization of commercially available photoresins in their neat state, as well as in polymer matrix composite (PMC) mixtures with various loading concentrations of the paraelectric barium strontium titanate (BST). Due to difficulties 3D printing the BST-loaded PMC resins detailed within, a custom curing and casting process was used to fabricate testable PMC samples, which were synthesized to demonstrate the dielectric functionalization of the underlying polymer matrix. Dielectric characterization of the PMCs confirmed the functionalization of our composites when compared to the commercial photoresins. For example, a volumetric loading concentration of 25 vol % BST increased the dielectric permittivity (εr) from 2.78 to 9.60 and the loss tangent (tanδ) from 0.022 to 0.114. These results indicate that the realization of UV-cured photoresins with “designer-dielectric” functionalization based on vol % of filler are strong candidates for use in stereolithography (SLA) 3D printing applications. To accomplish this, and with a special interest for radio/microwave/terahertz (RF/MW/THz) applications, we highlight the need for both (a) better photoresin matrix materials with lower intrinsic tanδ and (b) selection criteria related to the size/geometry and electronic properties of potential filler materials to maintain the printability of PMC photoresins in SLA systems.

A series of nanocomposites containing gold nanoparticles (AuNPs) are prepared by stereolithography (SL) by simply adding a precursor (KAuCl4) to a photoresist. A thermal treatment is performed after manufacturing the nanocomposites, triggering the reduction of KAuCl4 into AuNPs in solid state. In this approach, the photopolymerization of the resin and the formation of the AuNPs occur independently, allowing the optimization of these two processes separately. Advanced electron microscopy analyses reveal the distribution, size and morphology of the AuNPs synthesized within the resin, showing the influence of the gold precursor concentration and different thermal treatments. The localized surface plasmon resonance (LSPR) of the AuNPs modifies the optical properties of the 3D-printed nanocomposites, yielding transparent yet colored materials even for concentrations as low as 0.1 wt% KAuCl4. This behavior can be modelled by the Mie theory, correlating the macroscopic properties of the nanocomposites with the individual AuNPs embedded in the resin. The possibility of tuning the LSPR of the AuNPs together with the ability of manufacturing 3D-structures with sub-millimeter precision by SL, paves the way for the design of advanced platforms for plasmonics, such as sensors for surface enhanced Raman spectroscopy (SERS).

A Voronoi method is a feasible approach for developing biomimetic trabecular scaffolds. This study used algorithms based on scaling factors to design Voronoi scaffolds (pore sizes 600–1200 μm). Scaffolds were prepared from β-tricalcium phosphate slurry and 3D printed using stereolithography. Characterization analysis revealed that the microporous structures were correctly processed. Computational fluid dynamics indicated that scaffold permeability increased and the specific surface area decreased with increasing pore size, and the wall shear stress was highest in P800 scaffolds (pore size-800 μm). In addition, MC3T3 cells were dynamically seeded and were more evenly distributed and showed higher proliferation and differentiation on the P800 scaffold than the other three scaffolds in vitro. For in vivo experiment, scaffolds were implanted into rabbit femur to analyze the degradation and osteogenesis. Histological and imaging examinations revealed that new bone formation was more abundant on the surface and inside of the P800 scaffold than the other three scaffolds, which was explained by the hydrodynamic response. This study optimized a controllable method for designing Voronoi scaffolds and indicated that the pore size distribution of the P800 scaffold (458.8–989.1 μm) is an optimal choice for trabecular scaffolds.

We propose a novel additive manufacturing (AM) method that combines both powder-based and resin-based printing processes. Both resin-based and powder-based processes have unique advantages ranging from strength and variety of materials for powder processes, to resolution and surface finish for resin printing. Previously, we proposed a novel powder-based printing process that directs a laser beam upwards to fuse powders through glass to a substrate. However, this setup can also be used to solidify resin as a secondary material in the same print. We demonstrate this hybrid process by fabricating samples containing both resins and powders. We also examine the potential for resin to be used to reduce powder bed fusion part porosity as well as adjust part surface finish. We discuss the impacts of these results and propose future uses.

Objectives: This study aimed to develop and validate a robotic system capable of performing accurate and minimally invasive jawbone milling procedures in oral and maxillofacial surgery., Methods: The robotic hardware system mainly includes a UR5E arm (Universal Robots, Denmark) and the binocular positioning system (FusionTrack 250, Atracsys LLC, Switzerland). The robotic software (Dental Navi 3.0.0, Yakebot Technology Ltd., China) is capable of generating cutting tool paths based on three-dimensional shape description files, typically in the stereolithography format, and selected cutting tool parameters, as well as designing surgical accessories. Fully impacted supernumerary tooth models in the maxilla were fabricated using software and three-dimensional printing. Following the planning of a customized cavity to fully expose the tooth, maxillary bone milling was performed on both the robot and static guide groups (n = 8). After milling, all models underwent scanning for assessment., Results: In the experiment with fully buried supernumerary tooth models in the maxilla, the root mean square, translation error, over-removal rate, and maximum distance were significantly smaller in the robot group compared to the static guide group. Moreover, the overlap ratio and Dice coefficient were significantly greater in the robot group. No statistically significant differences were observed between the two groups in terms of the rotation error (P = 0.80) or under-removal rate (P = 0.92)., Conclusions: This study has developed a robotic system for milling individualized jawbone cavities in oral and maxillofacial surgery, and its accuracy has been preliminarily verified to meet clinical requirements., Clinical Significance: The robotic system can achieve precise, minimally invasive, individualized jawbone milling in a variety of oral and maxillofacial surgeries, including tooth autotransplantation, surgical reshaping for zygomatic fibrous dysplasia, removal of fully impacted supernumerary or impacted teeth, and endodontic microsurgery, among other relevant clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: We describe the development of 3D-printed stents using our digital workflow and their effects on patients enrolled in the lead-in phase of a multi-center, randomized Phase-II trial., Materials and Methods: Digital dental models were created for patients using intraoral scanning. Digital processes were implemented to develop the mouth-opening, tongue-depressing, and tongue-lateralizing stents using stereolithography. Time spent and material 3D-printing costs were measured. Physicians assessed mucositis using the Oral Mucositis Assessment Scale (OMAS) and collected MD Anderson Symptom Inventory (MDASI) reports and adverse events (AEs) from patients at various time points (TPs). OMAS and MDASI results were evaluated using paired t-test analysis., Results: 18 patients enrolled into the lead-in phase across 6 independent clinical sites in the USA. 15 patients received stents (average design and fabrication time, 8 h; average material 3D-printing cost, 11 USD). 10 eligible patients with complete OMAS and MDASI reports across all TPs were assessed. OMAS increased significantly from baseline to week 3 of treatment (mean difference = 0.34; 95 % CI, 0.09-0.60; p = 0.01). MDASI increased significantly from baseline to week 3 of treatment (mean difference = 1.02; 95 % CI, 0.40-1.70; p = 0.005), and week 3 of treatment to end of treatment (mean difference = 1.90; 95 % CI, 0.90-2.92; p = 0.002). AEs (grades 1-3) were reported by patients across TPs. Mucositis and radiation dermatitis were primarily attributed to chemoradiation., Conclusions: 3D-printed stents were successfully fabricated and well tolerated by patients. As patients enroll in the randomized phase of this trial, data herein will establish a baseline for comparative analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Objectives: To evaluate the fabrication trueness of additively manufactured maxillary definitive casts with various tooth preparations fabricated with different 3-dimensional (3D) printers and print orientations., Methods: A maxillary typodont with tooth preparations for a posterior 3-unit fixed partial denture, lateral incisor crown, central incisor and canine veneers, first premolar and second molar inlays, and a first molar crown was digitized with an industrial scanner. This scan file was used to fabricate definitive casts with a digital light processing (DLP) or stereolithography (SLA) 3D printer in different orientations (0-degree, 30-degree, 45-degree, and 90-degree) (n = 7). All casts were digitized with the same scanner, and the deviations within each preparation site were evaluated. Generalized linear model analysis was used for statistical analysis (α = 0.05)., Results: The interaction between the 3D printer and the print orientation affected measured deviations within all preparations (P ≤ 0.001) except for the lateral incisor crown and canine veneer (P ≥ 0.094), which were affected only by the main factors (P < 0.001). DLP-90 mostly led to the highest and DLP-0 mostly resulted in the lowest deviations within posterior tooth preparations (P ≤ 0.014). DLP-30 led to the lowest deviations within the first premolar inlay and DLP-45 led to the lowest deviations within the central incisor veneer preparation (P ≤ 0.045)., Conclusions: Posterior preparations of tested casts had the highest trueness with DLP-0 or DLP-30, while central incisor veneer preparations had the highest trueness with DLP-45. DLP-90 led to the lowest trueness for most of the tooth preparations., Clinical Significance: Definitive casts with tooth preparations fabricated with the tested DLP 3D printer and the print orientation adjusted on tooth preparation may enable well-fitting restorations. However, 90-degree print orientation should be avoided with this 3D printer, as it led to the lowest fabrication trueness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: The aim of this study was to assess the accuracy of surgical guides manufactured with four different 3D printers.., Methods: Forty-eight surgical guides (BlueSky Plan, BlueSky Bio) were produced using four different 3D printers, with strict adherence to each manufacturer's instructions. The printers used were three digital light processing (DLP) printers (SolFlex170, VC; Nextdent5100, ND, and D30+Rapidshape, RS) and one stereolithographic (SLA) printer (Formlabs3B+, FL). The study evaluated the trueness and precision of the overall surface, the region of interest (RoI) (occlusal and guide zone), the repeatability in several batches, and the guide hole's diameter and xyz axes. The printed guides were digitized and compared with the CAD design control specimen (Control X, Geomagic). Descriptive statistics and Kruskal-Wallis tests with post-hoc Mann-Whitney tests were performed (α=0.05)., Results: Differences in trueness and precision were found between groups in the overall zone and RoI (p = 0.00). The ND group demonstrated the highest repeatability. Only the RS group exhibited a comparable guide hole diameter to the master specimen (5.27±2.12 mm; p = 0.104). No statistical differences were observed between groups in the x and z axes. However, in the y-axis, the VC group displayed statistically significant differences (p = 0.01)., Conclusions: The results showed that the DLP groups had better overall accuracy, while the SLA group had the best results in the RoI. The manufacturer's workflows demonstrated a high reproducibility between batches in the RoI. The RS group had values most similar values to the guide hole diameter of the master specimen, with minimal deviations in guide hole orientation., Clinical Significance: Implant position can be affected by the accuracy of the 3D printed surgical guide. Therefore, it is critical to analyze the final dimensions and the direction of the guide hole using available printing technologies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Additive manufacturing (AM) has created a new era of digital manufacturing, where engineering practices, computer-aided design platforms, and part sourcing pipelines are dramatically changing. AM techniques are capable of producing plastic, metal, and ceramic components for both prototyping and end-use purposes. In this review, the fabrication of dense, structural advanced ceramic components using the seven families of additive manufacturing is discussed through a historical perspective. Initial studies on additive manufacturing of ceramic materials were reported just a few years after those of metal and plastic materials. However, industrial application of ceramic additive manufacturing is more than a decade behind metallic and plastic materials. Many of the challenges of ceramic AM can be traced back to the intrinsic difficulties of processing structural ceramic materials, including high processing temperatures, defect-sensitive mechanical properties, and poor machining characteristics. To mature the field of ceramic AM, future research and development should focus on expanding material selection, improving printing and post-processing control, realizing single-step processing, and unique capabilities such as multi-material and hybrid processing.

Presurgical planning forms an important aspect of craniofacial surgery which involves repositioning and reconstruction of facial and skull bones. Digital technology is being increasingly used for planning surgical procedures. Virtual surgical planning, Computer-aided design and Computer-aided modeling greatly improve the speed, scope and accuracy of surgery thereby providing better patient outcomes and satisfaction. In cases of craniofacial anomalies, cutting and positioning guides can be fabricated. For orthognathic surgery, realistic predictions of outcomes can be provided, in addition to improved presurgical planning. In maxillofacial trauma, facial height, width and projection can be better restored. TMJ/Skull base resection and reconstruction can be performed as single-stage operation. Intraoperative and graft ischemic time is reduced during oncologic resection and reconstruction. Potential limitation is added cost but this is offset by benefits like significantly reduced operating time, better dental alignment and improved esthetic outcome. In this review we attempt to briefly describe the historical developments, detail the application and assess the impact of technology for surgical planning and outcome.

The challenges associated with stereolithography-based ceramic additive manufacturing using high solid loading pastes are related to the printability of ultrathin layers and complex green bodies without auxiliary support structures directly underneath. In order to develop the strategy of conformal contactless support during additive manufacturing, the printability of alumina ceramic paste with a variety of solid loading, along with mechanical properties of the sintered parts fabricated by stereolithography process was investigated. A combination of scanning electron microscopy, micro-computed tomography scans and three-point bending tests were practiced systematically. The rheological behavior of ceramic paste was regulated distinctly by solid loading. As the solid loading increased, the degree of shrinkage decreased and the relative density increased for the sintered part. The sintered sample from 52 vol% ceramic paste presented the highest flexural strength with well densified microstructure. The research results promote property optimization of ceramic components fabricated by stereolithography method through material compositions and printability of ceramic paste, which simultaneously contributes to perfect support strategy for ceramic additive manufacturing.

Filigree lattice structures are sensible to geometrical imperfections and the scatter of material parameters which all depend on the stability of the manufacturing process. The aim of this study is to analyze these effects for polymer lattice structures and incorporate them in a finite element model for robust design. Micrographs of lattice structure slices show a smaller diameter for vertical struts. Basic mechanical tests on bulk material exhibit a tension–compression asymmetry which is captured with a Drucker-Prager material model in simulations. Digital image correlation measurements allow to determine true material properties. Plateau stress and failure strain are a result of the biggest flaw in the specimen. Hence, a new model to determine their probability distribution is proposed. This model outperforms standard approaches deriving the probability distribution from the central moments. A spatial correlation of geometric deviations and scatter of the material is investigated with variography subsequently allowing to model the varying properties with random fields. Simulations of dog-bone specimens show that the probability distributions of material properties are captured well. Also simulations of lattice structures are able to represent the probability distributions of their homogenized mechanical properties. The whole stress–strain response and the failure progression agree well with experimental results.

Macroporous calcium pyrophosphate ceramics with a pore size of 900 μm and a pore fraction of up to 65% demonstrating compressive strength of 5 ± 1 MPa were formed by DLP stereolithography 3D printing. Mixed sodium-calcium pyrophosphate CaNa2P2O7 was used as an eutectic additive in liquid phase sintering of the ceramics at 600–800 °C. Initial powder charge was selected from a mixture of Ca10(PO4)6(OH)2, Ca(H2PO4)2·H2O and NaH2PO4. The pH of the aqueous solution contacting with the manufactured pyrophosphate ceramics in the range (6–7.2) turns out to be acceptable for further biomedical tests as a bone grafting material.

Digital light processing (DLP) stereolithography was used to prepare layers and samples for dimensional calibration from commercial alumina slurries. Single-layer squares were studied to understand the penetration depth and curing behavior, and samples with varying curing time and intensity were printed and sintered. Fourier-transform infrared spectroscopy (FTIR) of the squares was performed to measure the relative amount of curing based on the change of the bond transparency of the polymer during various printing conditions. X-ray computed tomography (XCT) scans were performed after printing of squares and parts as well as after sintering parts. The morphologies and structures of the squares and parts were studied after printing and after sintering. The dimensions were measured, and the differences before and after sintering are reported for the various printing conditions. The study shows how FTIR can monitor curing of printed parts, and dimensional accuracy of 0.20 mm can be achieved.

Background: Three-dimensional (3D) printing technologies have become popular in orthodontics. The aim of this study is to determine the effect of printing technology, orientation, and layer height on the accuracy of 3D-printed dental models., Methods: The maxillary arch of a post-treatment patient was scanned and printed at different orientations (0°, 90°) and layer thicknesses (25 µm, 50 µm, 100 µm, and 175 µm) using two different printing technologies (digital light processing and stereolithography). The 120 models were digitally scanned, and their average deviation from the initial model was analyzed using 3D algorithm. A multivariable linear regression analysis was used to estimate the effect of all variables on the average deviation from the initial model for the common layer thicknesses (50/100 µm). Finally, one-way ANOVA and Tukey posthoc test was used to compare the stereolithography (SLA) 25 µm and digital light processing (DLP) 175 µm groups with the groups that showed the least average deviation in the former analysis., Results: The multivariable linear regression analysis showed that the DLP 50 µm (mean ± SD: -0.022 ± 0.012 mm) and 100 µm (mean ± SD: -0.02 ± 0.009 mm) horizontally printed models showed the least average deviation from the initial model. Finally, the DLP 175 µm horizontally printed models (mean ± SD: 0.015 ± 0.005 mm) and the SLA 25 µm horizontally (mean ± SD: 0.011 ± 0.005 mm) printed models were more accurate., Conclusions: All the models showed dimensional accuracy within the reported clinically acceptable limits. The highest accuracy was observed with DLP printer, 175 µm layer thickness, and horizontal orientation followed by SLA printer, 25 µm layer thickness, and horizontal orientation., (Copyright © 2024 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: To report the clinical results obtained with fixed short-span (single crowns [SCs] and fixed partial prostheses [FPPs]) implant-supported hybrid composite restorations fabricated through tilting stereolithography (TSLA)., Methods: This retrospective clinical study included 85 patients who had been restored with 95 fixed short-span implant-supported hybrid composite (Irix Max®, DWS Systems) restorations (70 SCs and 25 FPPs up to three units) fabricated with TSLA. The full-digital model-free workflow was based on intraoral implant scanning, computer-assisted design (CAD) and 3D printing using TSLA (Dfab®, DWS Systems). The primary outcomes were the marginal adaptation, the quality of the occlusal and interproximal contact points, and the chromatic integration of the restorations, assessed independently by two experienced operators (a prosthodontist and a periodontist). A score from 1 to 5 (with 5 as the highest value, 4 for satisfactory quality, 3 for acceptable quality, and 2 and 1 as the lowest values, expressing unsatisfactory quality) was assigned by each operator to each restoration at delivery. The secondary outcomes were the survival and success of the restorations at the 1-year follow-up. The restoration was defined as successful in the absence of any complications throughout the follow-up period. A statistical analysis was conducted., Results: For the quality of the marginal closure and occlusal and interproximal contact points, the 3D-printed hybrid composite restorations scored highly; the aesthetic integration was satisfactory. One year after placement, all restorations survived, with a low incidence (4.2 % overall, 5.7 % SCs) of complications (two abutment screw loosenings, two decementation of the restorations, and one upper portion of the hybrid abutment decemented from the titanium base), for a success rate of 95.8 %., Conclusions: Within the limits of this study (retrospective design, follow-up limited to 1 year from the delivery, and only cemented restorations included) fixed short-span implant-supported hybrid composite crowns and bridges fabricated through TSLA were clinically precise, presenting a low incidence of complications at 1 year., Statement of Clinical Relevance: The use of TSLA printing technology can open new perspectives for the treatment of small edentulous gaps with definitive implant-supported prosthetic restorations., Competing Interests: Declaration of competing interest The authors report no conflict of interest related to the present clinical study. The materials presented in the study belong to the authors, who have not received any grant or financial support for the preparation of the present research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Recently, the replication of biological microstructures has garnered significant attention due to their superior flexural strength and toughness, coupled with lightweight structures. Among the most intriguing biological microstructures renowned for their flexural strength are those found in the Euplectella Aspergillum (EA) marine sponges. The remarkable strength of this sponge is attributed to its complex microstructure, which consists of concentric cylindrical layers known as spicules with organic interlayers. These features effectively impede large crack propagation, imparting extraordinary mechanical properties. However, there have been limited studies aimed at mimicking the spicule microstructure. In this study, structures inspired by spicules were designed and fabricated using the stereolithography (SLA) 3D printing technique. The mechanical properties of concentric cylindrical structures (CCSs) inspired by the spicule microstructure were evaluated, considering factors such as the wall thickness of the cylinders, the number of layers, and core diameter, all of which significantly affect the mechanical response. These results were compared with those obtained from solid rods used as solid samples. The findings indicated that CCSs with five layers or fewer exhibited a flexural strength close to or higher than that of solid rods. Particularly, samples with 4 and 5 cylindrical layers displayed architecture similar to natural spicules. Moreover, in all CCSs, the absorbed energy was at least 3-4 times higher than solid rods. Conversely, CCSs with a cylinder wall thickness of 0.65 mm exhibited a more brittle behavior under the 3-point bending test than those with 0.35 mm and 0.5 mm wall thicknesses. CCSs demonstrated greater resistance to failure, displaying different crack propagation patterns and shear stress distributions under the bending test compared to solid rods. These results underscore that replicating the structure of spicules and producing structures with concentric cylindrical layers can transform a brittle structure into a more flexible one, particularly in load-bearing applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: This in vitro study aimed to compare the accuracy of dental implant placement in partially edentulous maxillary models using a mixed reality-based dynamic navigation (MR-DN) system to conventional static computer-assisted implant surgery (s-CAIS) and a freehand (FH) method., Methods: Forty-five partially edentulous models (with teeth missing in positions #15, #16 and #25) were assigned to three groups (15 per group). The same experienced operator performed the model surgeries using an MR-DN system (group 1), s-CAIS (group 2) and FH (group 3). In total, 135 dental implants were placed (45 per group). The primary outcomes were the linear coronal deviation (entry error; En), apical deviation (apex error; Ap), XY and Z deviations, and angular deviation (An) between the planned and actual (post-surgery) position of the implants in the models. These deviations were computed as the distances between the stereolithographic (STL) files for the planned implants and placed implants captured with an intraoral scanner., Results: Across the three implant sites, the MR-DN system was significantly more accurate than the FH method (in XY, Z, En, Ap and An) and s-CAIS (in Z, Ap and An), respectively. However, S-CAIS was more accurate than MR-DN in XY, and no difference was found between MR-DN and s-CAIS in En., Conclusions: Within the limits of this study (in vitro design, only partially edentulous models), implant placement accuracy with MR-DN was superior to that of FH and similar to that of s-CAIS., Statement of Clinical Relevance: In vitro, MR-DN showed greater accuracy in implant positioning than FH, and similar accuracy to s-CAIS: it could, therefore, represent a new option for the surgeon. However, clinical studies are needed to determine the feasibility of MR-DN., Competing Interests: Declaration of competing interest The authors report no conflict of interest related to the present in vitro study. Dr. Ariel Shusterman is an employee of MARS, but the materials presented in the study belong to all the authors, who have not received any grant or financial support for the preparation of the present research., (Copyright © 2024. Published by Elsevier Ltd.)

The printed features on an additive manufactured part will often deviate from the nominal values of the 3D model's features due to the factors such as printer resolution, printing parameters, printing technology, and the measurement method. The National Institute of Standards and Technology (NIST) standard test artifact contains a collection of various features that can be used to characterize a 3D printer's performance and has been used to benchmark metal printers. There is limited documentation on how well different additive manufacturing processes can fabricate the NIST artifact. This dataset records the dimensional uncertainty of selective printed features of the NIST artifact manufactured with polymer and resin printing processes. It contains the post-processing dimensional measurements of geometric features on the printed test artifacts. In order to generate the data, a total of 16 samples of the test artifact were printed with fused deposition modelling (FDM) and stereolithography (SLA) additive manufacturing methods. The percentage error between the measurement of features in the printed samples and their nominal computer aided design (CAD) values are calculated. For future reusability of this data, the same NIST test artifact CAD model can be printed, and the features’ measurements can be compared with the dataset presented in this article.

Propellants are the main energy source in the internal ballistic process. The use of 3D printing has promised to produce propellants with complex geometries. However, due to the degraded energy properties of propellants using an inert binder, there is a critical need to develop a printable energetic resin. In this paper, a novel energetic acrylate-terminated poly–3–nitratomethyl–3–methyloxetane (APNIMMO) oligomer was prepared and characterized. The performance of a new composite propellant composed of APNIMMO and CL-20 (Hexanitrohexaazaisowurtzitane Dodecane) was also demonstrated. The new energetic printable resin and its composites are suitable for stereolithography (SLA) 3D printing, offering not only an improved thermodynamic energy, but also a substantially improved burn rate. Compared with the inert binder, the energetic binder offers the possibility to improve the thermodynamic energy by 15% and the burn rate at 100 MPa by 480% for 3D printed propellants.

With the median age of the population steadily rising, the rate of bone disorders increases as well, making the need of bone implants more and more urgent in our society. However, manufacturing of synthetic bioimplants requires high flexibility of the process and materials with sufficient mechanical strength and biocompatible properties. This paper is devoted to the printing of β-tricalcium phosphate (β-TCP) by stereolithography. The suspensions or pastes containing the photosensitive-resin mixed with β-TCP powder were assessed for the following parameters: rheological behaviour, thermal degradation of photo-cured samples, quality of green and sintered parts. It appeared that the composition of the photo-sensitive resin influences the viscosity of the paste. However, no direct correlation could be drawn between the viscosity of the photo-sensitive resins and the viscosity of the whole paste. A hypothesis is that the chemical structure of the monomers composing the photo-sensitive resin also impacts the viscosity of the paste. A thermal debinding cycle was built from the thermogravimetric analysis of the photo-cured samples. The structure of the post printed (green) parts and final parts (parts after debinding and sintering) was evaluated. It appeared that the pastes with the lowest viscosity were the easiest to process, and that the green parts made with these pastes were the easiest to clean, reducing the number of defects in the sintered parts. Process optimisation was also assessed. Different light parameters were evaluated, and it appeared that reducing the light power during the printing improved the resolution as well as the quality of the sintered parts.

In this study, poplar wood flour at various concentrations (1–10 wt%) is incorporated into a methacrylate-based resin via solution blending to fabricate wood-reinforced composites using stereolithography apparatus (SLA) 3D printing. Differential scanning calorimetry (DSC) along with Fourier transform infrared spectroscopy (FTIR) analysis shows the presence of a small amount of residual monomer in the printed samples. For the printed composites, the glass transition temperature (Tg) from dynamic mechanical analysis (DMA) decreases as more wood flour is incorporated, which indicates an increase in free volume occupied by polymer chains. The tensile strength is improved up to 17.3% from 21.1 MPa (no wood flour) to 24.7 MPa (1.0 wt% wood flour). The highest Young’s modulus reaches 323.8 MPa (2.0 wt% wood flour), which is 1.9-fold of that of the sample without wood flour. Moreover, the composites show “stress whitening” with the addition of wood flour during the uniaxial drawing. Morphology analysis of the tested samples show that the formation of microcraze and microvoids likely causing the stress whitening. This is the first study that demonstrates wood flour can be utilized in SLA 3D printed wood plastic composites (WPC) which can reinforce the printed products with a modest loading amount.

In this work, biocomposites based on hydrogels filled with calcium phosphates were fabricated using DLP method of 3D printing for the treatment of bone defects. The possibility to tune the functional properties of hydrogels such as degradation, swelling, and mechanical behavior by using a mixture of monomers with different functionality and different calcium phosphates was shown. Mechanical properties, photopolymerization, swelling behavior, and microstructure of hydrogels based on a mixture of poly(ethylene glycol) methacrylate/poly(ethylene glycol) diacrylate (PEGMA/PEGDA) monomers with different composition were studied. It was found that the usage of α-tricalcium phosphate (α-TCP) powder as a filler for hydrogels allowed to increase the filler fraction up to 60 ​wt% in comparison with octacalcium phosphate (OCP) and brushite (10 ​wt%) without significant thickening of photosuspension for DLP printing. Finally, the main parameters of DLP printing for biocomposites based on PEGMA/PEGDA hydrogels were found, and the macroporous biocomposite filled with 60 ​wt% α-TCP with gyroid structure was obtained.

The manufacturing of ceramic green parts using the stereolithography process requires several steps, which can each influence the mechanical properties of the printed parts: dimensional precision, surface roughness and mechanical strength. The part orientation with respect to the working plan and adapted supports are key points to avoid the failure of the green part during its construction. Indeed, mechanical forces generated during the spreading of thin layers of ceramic suspension generate significant loads on the green part being printed and may displace it or lead to its rupture. It is then crucial to choose a part orientation that minimize these effects and to create adapted supports that can hold the scraping loads. In this respect, a finite element simulation of scraping is performed to analyze the best green part orientation and adapted supports during the stereolithography process. A specific and original experiment is developed to identify the scrapings loads, essential as input data for the simulation. Modellings confirms that the orientation of the support greatly influences the deformations of the green part and highlights the importance of the support stiffness that absorb the scraping forces.

The integration of shape memory materials into additive manufacturing has added a new dimension of time to conventional 3D printing and enabled innovative product designs with high tailorability and adaptability. To date, most studies on shape memory effects mainly adopt experimental approaches to characterize the material responsiveness to various stimulation conditions considering a single thermomechanical loading cycle. The information regarding the cyclic shape memory behaviors as well as the potential additive manufacturing-induced impacts on the achieved shape memory performance is limited. In this paper, the shape memory behaviors of the stereolithography printed thermo-responsive structures are theoretically modeled by jointly considering the influences from both the printing process and the shape memory process. The cyclic shape memory effects are analytically characterized and experimentally validated using methacrylate copolymers under iterative thermomechanical loadings. Meanwhile, case studies are presented to provide insights into shape memory behaviors upon the impacts of various levels of critical process parameters. The results indicate an exceptional prediction accuracy of 96.24% and 95.73% for the established shape fixity and recovery models, respectively. It is also observed that the printing process parameters, including layer thickness and scan speed, have considerable impacts on the shape memory performance of the printed parts.

The key to any presence in space being sustainable is the ability to manufacture the necessary structures and spares in situ and on-demand, in order to avoid the cost, volume, and up-mass constraints that would prohibit a successful launch with everything needed for long-duration and long-distance missions from Earth. In terms of meeting the demand for parts with highly complex geometries and high accuracy, ceramic stereolithography is a revolutionary manufacturing technology, with oxide ceramics being widely studied due to their low levels of light absorption and scattering. This article investigates the feasibility of producing parts from lunar regolith simulant using a vat polymerization (VP) technique called lithography-based ceramic manufacturing (LCM). The conducted analyses include determining the rheological behavior of the suspension and the thermogravimetric characterization of printed green parts, as well as examining the mechanical, structural and microstructural properties through compression tests, computed tomography and SEM of sintered regolith samples.

This paper reports on a novel solution to 3D print bulk components by stereolithography with photosensitive ceramic-based slurries. We designed, realized and tested a novel apparatus, characterized by a UV transparent platform and a silicone flexible film under tension, which cures layers of ceramic slurries exploiting the “top-down” approach. This new device guarantees a precise slice thickness between the transparent wall and the mating slice, allowing the precise building of bulk green ceramic components. The device can 3D print viscous photosensitive ceramic slurries (i.e. viscosity up to 10 ​Pa ​s at 10 s−1 shear rate). Moreover, the apparatus allows for the production of complex bulk components where the adhesion forces are high. This permits to widen the range of geometrical features of 3D printed objects printable by common stereolithography.

Background: There is a quest of novel functional and reliable platforms for enhancing the efficiency of microextraction approaches in troublesome matrices, such as industrial wastewaters. 3D printing has been proven superb in the analytical field to act as the springboard of microscale extraction approaches., Results: In this work, low-force stereolithography (SL) was exploited for 3D printing and prototyping bespoke fluidic devices for accommodating nonsupported microelectromembrane extraction (μEME). The analytical performance of 3D-printed μEME devices with distinct cross-sections, including square, circle, and obround, and various channel dimensions was explored against that of commonly used circular polytetrafluoroethylene (PTFE) tubing in flow injection systems. A computer-controlled millifluidic system was harnessed for the (i) automatic liquid-handling of minute volumes of donor, acceptor, and organic phases at the low μL level that spanned from 3 to 44 μL in this work, (ii) formation of three-phase μEME, (iii) in-line extraction, (iv) flow-through optical detection of the acceptor phase, and (v) solvent removal and regeneration of the μEME device and fluidic lines. Using methylene blue (MB) as a model analyte, experimental results evinced that the 3D-printed channels with an obround cross-section (2.5 mm × 2.5 mm) were the most efficient in terms of absolute extraction recovery (59%), as compared to PTFE tubing of 2.5 mm inner diameter (27%). This is attributed to the distinctive convex interface of the organic phase (1-octanol), with a more pronounced laminar pattern, in 3D-printed SL methacrylate-based fluidic channels against that of PTFE tubing on account of the enhanced 1-octanol wettability and lower contact angles for the 3D-printed devices. The devices with obround channels were leveraged for the automatic μEME and in-line clean-up of MB in high matrix textile dyeing wastewater samples with relative recoveries ≥81%, RSD% ≤ 17.1% and LOD of 1.3 mg L - 1 . The 3D-printed nonsupported μEME device was proven superb for the analysis of wastewater samples with an elevated ionic strength (0.7 mol L -1 NaCl, 5000 mg L -1 Na 2 CO 3 , and 0.013 mol L -1 NaOH) with recorded electric currents below 12 μA., Novelty: The coupling of 3D printing with nonsupported μEME in automatic flow-based systems is herein proposed for the first time and demonstrated for the clean-up of troublesome samples, such as wastewaters., Competing Interests: Declaration of competing interest The authors declare that there are no known conflicts of interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Different printing technologies can be used for prosthetically oriented implant placement, however the influence of different printing orientations and steam sterilization remains unclear. In particular, no data is available for the novel technology Continuous Liquid Interface Production. The objective was to evaluate the dimensional accuracy of surgical guides manufactured with different printing techniques in vertical and horizontal printing orientation before and after steam sterilization. A total of 80 surgical guides were manufactured by means of continuous liquid interface production (CLIP; material: Keyguide, Keyprint), digital light processing (DLP; material: Luxaprint Ortho, DMG), stereolithography (SLA; Surgical guide, Formlabs), and fused filament fabrication (FFF; material: Clear Base Support, Arfona) in vertical and horizontal printing orientation (n = 10 per subgroup). Spheres were included in the design to determine the coordinates of 17 reference points. Each specimen was digitized with a laboratory scanner after additive manufacturing (AM) and after steam sterilization (134 °C). To determine the accuracy, root mean square values (RMS) were calculated and coordinates of the reference points were recorded. Based on the measured coordinates, deviations of the reference points and relevant distances were calculated. Paired t-tests and one-way ANOVA were applied for statistical analysis (significance p < 0.05). After AM, all printing technologies showed comparable high accuracy, with an increased deviation in z-axis when printed horizontally. After sterilization, FFF printed surgical guides showed distinct warpage. The other subgroups showed no significant differences regarding the RMS of the corpus after steam sterilization (p > 0.05). Regarding reference points and distances, CLIP showed larger deviations compared to SLA in both printing orientations after steam sterilization, while DLP manufactured guides were the most dimensionally stable. In conclusion, the different printing technologies and orientations had little effect on the manufacturing accuracy of the surgical guides before sterilization. However, after sterilization, FFF surgical guides exhibited significant deformation making their clinical use impossible. CLIP showed larger deformations due to steam sterilization than the other photopolymerizing techniques, however, discrepancies may be considered within the range of clinical acceptance. The influence on the implant position remains to be evaluated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)