ABSTRACT This study presents a comprehensive experimental–numerical investigation of the load‐bearing behaviour of octahedral and pillar‐reinforced octahedral lattice structures fabricated via stereolithography (SLA) using a bio‐based UV‐curable KS408B (PAR‐based) resin. Lattice specimens were produced with three nominal strut thicknesses (300, 400 and 500 μm), enabling systematic variation of infill density and architectural stiffness. Mechanical performance was evaluated under compression, shear and torsional loading to capture geometry‐dependent responses across multiple deformation modes. Experimental results reveal a pronounced nonlinear sensitivity of mechanical properties to slight variations in infill density at low porosity. At a strut thickness of 300 μm, a modest increase of 1.7 percentage points in infill density resulted in a 255% increase in elastic modulus and a 63% increase in compressive yield stress. Under shear loading, pillar‐reinforced lattices exhibited enhancements of up to 86% in shear modulus and 33% in yield stress compared to the pure octahedral topology. Torsional tests further demonstrated geometry‐dependent trade‐offs: pillar reinforcement generally improved torque capacity, whereas the octahedral architecture exhibited greater deformation tolerance and stress homogenization. Finite element analysis (FEA), incorporating experimentally measured bulk material properties, showed good agreement with experimental data, particularly for yield‐related parameters, with deviations of 3%–14%, while stiffness‐related deviations remained within 16%–26%. Stress distribution analyses highlighted increased rigidity and localized stress concentrations in pillar‐reinforced structures, in contrast to the more uniform stress fields observed in pure octahedral lattices. Overall, this work establishes a unified multi‐loading experimental–numerical framework for evaluating SLA‐fabricated porous lattices and provides new quantitative insights into the interplay between lattice geometry, infill density and mechanical efficiency. The findings offer practical design guidelines for tailoring architectured polymeric structures for load‐bearing biomedical scaffolds and lightweight structural applications, where balancing stiffness, strength and deformation capability is critical.

This study explores the passive separation of solid particles from liquid suspensions in spiral separators fabricated using fused filament fabrication (FFF) and stereolithography (SLA). Building on prior work, we investigate the effect of microchannel geometry, circular vs. square cross-sections of equal area, and printing method on separation performance. Devices were tested across a wider range of flow rates (150 mL min−1–350 mL min−1), extending into transitional regimes, to examine geometry-induced inertial effects. Separation performance was quantified using the normalized outlet mass difference (Δ) for talc, precipitated calcium carbonate, and quartz. Maximum separation was obtained for quartz sand in the SLA separator at 250 mL min−1 (Δ = 0.2175 g per 100 mL), while talc showed the highest mass difference in the square FFF separator at 300 mL min−1 (Δ = 0.1196 g per 100 mL). For calcium carbonate, the highest separation occurred in the SLA device at 250 mL min−1 (Δ = 0.1721 g per 100 mL), though performance was limited by agglomeration and clogging in FFF devices. Overall, separation was predominantly mass-based rather than strictly size-selective, with channel geometry, flow regime, and fabrication method jointly governing performance.

The development of an image processing model to estimate tooth width and space requirements.

Background/Objectives: The growing demand for personalised, patient-centric drug delivery systems has driven innovation in pharmaceutical manufacturing, particularly in multi-unit particulate systems (MUPS). Methods: In this study, inert cores with tailor-made geometry for multi-particulate formulations were fabricated with high-resolution stereolithography (SLA) 3D printing. By a printable photopolymer resin, dimensionally accurate and mechanically robust starter cores were produced. The additively manufactured inert subunits were drug-layered with ibuprofen sodium using a fluidised bed process. Then, a controlled-release film coating of Eudragit RS 30D was applied with varying coating thicknesses. The initial 3D-printed subunits, together with the drug-layered and finally film-coated microparticles, were characterised by image analysis, Raman microspectroscopic measurements, and official methods of the European Pharmacopoeia. Results: The combined approach of 3D printing and traditional pharmaceutical processing proved highly effective. The 3D-printed cores demonstrated both flexibility in design and consistency in performance. Conclusions: These findings highlight the feasibility of using 3D printing to produce patient-specific, functional cores in multi-particulate systems that can be easily modified according to the patient’s needs. The fabricated minitablets can be used as alternatives to widely used inert cores. Integrating additive manufacturing with conventional coating techniques offers promising new avenues for developing next-generation, personalised drug delivery solutions.

ABSTRACT Vat polymerization (VP) 3D printing, a light‐based additive manufacturing technique, has emerged as a promising technique for fabricating complex drug delivery systems with high precision and spatial resolution. This layer‐by‐layer manufacturing process enables the creation of intricate geometries and customizable architectures, which are particularly advantageous for controlling drug release profiles to meet patient‐specific therapeutic needs. Its application in drug release systems is gaining traction in both research and clinical domains, especially for producing controlled‐release tablets, implants, and localized drug delivery devices. This review offers a comprehensive overview of the VP process and 3D printing technologies that utilize this process including stereolithography (SLA), digital light projection (DLP), Continuous liquid interface production (CLIP), two‐photon polymerization (2PP), and volumetric VP. Furthermore, common biocompatible and biodegradable materials used in the VP process, some process parameters, and clinically relevant drug delivery applications are discussed. The benefits, drawbacks, and challenges with utilizing VP 3D printing in the drug delivery space are also discussed. Addressing these challenges is essential in advancing the clinical translation of VP 3D printing in controlled drug delivery applications.

This paper investigates the feasibility of manufacturing hydraulic fittings using additive manufacturing (AM) technologies, specifically Fused Deposition Modeling (FDM) and Stereolithography (SLA). The study addresses the environmental challenge of material waste in conventional fitting production by exploring 3D printing as an alternative manufacturing method. Hydraulic fittings were designed using CAD software: SolidWorks 2022 and fabricated using FDM with PETG (Polyethene Terephthalate Glycol) material and SLA with UV-sensitive photopolymer resin. In present studies, on-destructive leak testing was conducted in accordance with PN-EN 1254-4 and PN-EN 1254, at pressures ranging from 0.1 to 1.0 bar. Dimensional accuracy analysis revealed shrinkage of approximately 1% for SLA-printed parts and 2% for FDM-printed parts. Microscopic examination at 50× and 80× magnification showed superior thread quality in SLA samples compared to FDM, which exhibited visible layer separation and material porosity. Leak testing demonstrated that while the brass reference fitting maintained complete seal integrity, both 3D-printed variants failed to achieve leak tightness under operational pressures, with structural failure occurring at 1.0 bar during tightening. The study showed that FDM with PETG material and SLA with UV-sensitive photopolymer resin, despite achieving acceptable dimensional tolerances (±1-2%), do not meet hydraulic leak tightness requirements at pressures exceeding 0.5 bar in their raw state after printing. The results suggest that alternative material formulations (e.g., carbon fiber-reinforced PEEK for FDM or epoxy engineering resins for SLA) warrant further investigation. Potential avenues for improvement include advanced surface treatment, optimization of printing parameters, and modifications to thread geometry to reduce interthread gaps.

To summarize and synthesize evidence-based conclusions on optimal three-dimensional (3D) printing technologies, materials, and clinical protocols for splints, crowns, and dentures. In resin vat printing, stereolithography (SLA) offers superior surface finish, while liquid crystal display (LCD) and digital light processing (DLP) excel in speed for larger prints, with LCD providing a cost advantage. Ceramic vat printing yields clinically acceptable strength but is equipment- and time-intensive. Optimal angulation varies by application: splints (0°), crowns (150°-210°), dentures (45°-90°). A 50 μm layer height is preferred for most restorations, with dentures tolerating 100 μm. Commonly used resins employ low-viscosity monomers (e.g., ethoxylated bisphenol A dimethacrylate [Bis-EMA]) that limit stiffness and fast photoinitiators (e.g., ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate [TPO]), requiring 385-405 nm curing. Flexible splints excel in fracture toughness and impact strength; firm splints match milled wear performance. Printed crowns, while weaker than milled options, offer toughness; wear rates remain a concern. Printed denture bases vary in strength but can match or exceed conventional options; printed teeth show favorable wear resistance. Postprocessing, polishing, and bonding protocols critically influence outcomes. Employing validated printing parameters, selecting the appropriate resin, and following evidence-based protocols allows clinicians to maximize restoration accuracy and mechanical performance while leveraging 3D printing's efficiency and cost benefits.

3D printing has emerged as a practical method for fabricating customisable, accurate and affordable dental training models. Numerous 3D printing technologies exist, though there is no standardised comparison to inform their implementation in dental education. This study aimed to evaluate and compare the qualities of various 3D printed dental models against the current standard model used in tertiary dental education. Five maxillary molar tooth models were fabricated using selective laser sintering (SLS), fused filament fabrication (FFF), material jetting (MJ), stereolithography (SLA) and digital light processing (DLP). A standard Ivorine tooth model (One Dental, Australia) was also evaluated. Eighteen participants performed cavity preparations and assessed each model based on haptic feedback, visual appearance, anatomical accuracy and overall suitability using a 5-point Likert scale. FFF was the most economical per unit ($0.06), followed by DLP ($0.30). MJ was the most expensive ($1.87), though it offers high resolution and complexity. In terms of enamel haptics and dentine haptics, MJ (3.11, 3.28), SLA (3.00, 3.33) and DLP (3.11, 3.44) were assessed as comparable to Ivorine (3.67, 3.44). Similarly, overall suitability of MJ (3.33), SLA (3.33) and DLP (3.44) was comparable to Ivorine (4.17). FFF and SLS were rated significantly inferior to Ivorine in all domains. Current 3D printed models do not fully simulate dental tissue and should be used to supplement the limitations of standard models and improve self-learning. Future research is warranted to develop models with improved haptic feedback and realistic surface anatomy.

Interstitial fluid (ISF) is the extracellular fluid within the dermis that transports biomolecules diffusing from blood vessels to lymphatic vessels. Owing to its blood-like composition and accessibility only a few millimeters beneath the skin surface, ISF has recently attracted considerable attention as a minimally invasive reservoir for biomarker analysis. Conventional ISF collection relies on invasive sampling methods. Microneedle (MN) technology has emerged as a promising approach for developing minimally invasive ISF sampling and analysis systems. We present a design and one-step stereolithography (SLA)-based 3D printing fabrication of a wearable hollow MN device: μHolloSense. The device is capable of negative pressure-assisted ISF collection via its syringe port and is compatible with lateral flow assay (LFA) testing through a dedicated test port. The overall cost was ∼$1 per single-use device, including all components, and $1.50 per SARS-CoV-2 antigen test, used here as a proof-of-concept LFA system. Additionally, a 3D-printed, agarose-based skin-mimicking platform was developed to provide a standardized tool for evaluating MN sampling performance. Beyond this model system, ex vivo skin experiments were conducted to validate the applicability of μHolloSense for ISF collection in biologically relevant tissues. Our results demonstrate that μHolloSense, featuring a refined tip diameter (44.19 ± 2.4 μm) and height (1207.93 ± 11.25 μm), is capable of drawing liquids at a rate sufficient to reach the dermis, exhibiting robust mechanical properties (>0.17 N compressive force per needle) in IgG LFA tests across antigen concentrations of 1, 10, 100, and 250 pg mL-1. Ex vivo experiments on mice skin confirmed ISF extraction of up to 6 μL per sampling, with protein concentrations consistent with physiological levels. Collectively, this work presents a unified strategy for the design, fabrication, and evaluation of 3D-printed hollow MN systems with an integrated negative-pressure approach for ISF-based biomolecule analysis. In the future, further optimization and clinical validation of this platform would enable continuous, minimally invasive monitoring of a wide range of biomarkers, paving the way for point-of-care diagnostic and personalized health applications.

Accuracy of implant-supported crowns fabricated by additive and subtractive manufacturing technologies using ceramic-filled resins: An in vitro study.

Influence of three chemical disinfection protocols on the mechanical, physical, and cytotoxic properties of additively manufactured complete denture bases with and without soft reline resin: An in vitro study.

Over time, the methods for creating dental models have expanded significantly. Nowadays, digital technology and computers in medicine offer more options beyond plaster casts made using the traditional method. The advancement of computer-aided design and computer-aided manufacturing (CAD/CAM) systems provides a broad array of technologies, including both subtractive and additive techniques.The main purpose of this paper is to present the various modern three-dimensional printing systems concerning the fabrication of dental models and subsequently compare them both with each other and with the traditional technique of plaster model fabrication. A description of the main methods of additive manufacturing (AM; also referred to as 3D printing) for dental models is provided, along with bibliographic data regarding their accuracy and effectiveness, as well as comparisons with traditional manufacturing methods. The results of this paper indicate that stereolithography (SLA), digital light processing (DLP), and PolyJet technologies are the most precise choices for producing full arch dental models for prosthodontic use, offering high levels of trueness.Using digital tools and software, AM creates desired casts layer by layer, streamlining the production of complex, customized dental models with high speed, accuracy, and lower costs. The clinical significance of 3D-printed dental models is multifaceted, offering improvements in accuracy, efficiency, communication, education, cost-effectiveness, and innovation in dental practice. These technological advancements contribute to providing higher-quality care and better outcomes for patients.

This study aimed to optimize additive manufacturing parameters with a specific focus on improving the mechanical performance of materials used for sports mouthguards. The objective was to evaluate impact resistance and fracture behavior as the primary criteria for optimization. Two additive manufacturing techniques, Fused Deposition Modeling (FDM) and Stereolithography (SLA), were evaluated using four materials: TPU, EVA, DIMA resin, and IBT resin. Specimens were produced under varying layer thicknesses, printing orientations, and raster/angle configurations. Mechanical performance was assessed through Izod impact testing, and fracture morphology was analyzed using scanning electron microscopy (SEM). Printing parameters significantly influenced impact resistance across all materials. Under optimized SLA conditions (25 μm, vertical, 90°), DIMA exhibited an impact resistance of 25.6 ± 0.14 kJ/m2, while IBT reached 8.64 ± 1.16 kJ/m2. For FDM materials, TPU achieved the highest performance at 31.2 ± 1.29 kJ/m2, followed by EVA with 21.8 ± 0.35 kJ/m2, both printed at 0.08 mm layer height, 60 mm/s, and 90° raster orientation. SEM analysis confirmed that optimized parameters reduced interlayer defects and improved fracture resistance in both technologies. Additive manufacturing demonstrated for producing mechanically efficient mouthguard materials when printing parameters are appropriately optimized. TPU and EVA printed via FDM showed impact resistance comparable to commercial EVA, while optimized SLA parameters enhanced resin performance despite inherent brittleness. These findings reinforce AM as a viable alternative for customizable, mechanically optimized mouthguard fabrication.

Comparison of stereolithography (STL) and polygon file format (PLY) for intraoral scans: From chairside to archive.

Casting of PDMS microfluidics into 3D printed moulds and their application in capillary electrophoresis.

Intraoral appliances are widely used in dentistry. Their surface roughness may influence patient comfort, biofilm formation and durability. The aim of the study was to evaluate and compare the effect of thermocycling on the surface roughness (Ra) of different materials used for the fabrication of intraoral appliances. Seventy-two standardized specimens (40 mm × 10 mm × 2 mm) were fabricated from 3 materials: a self-curing poly(methyl methacrylate) (PMMA) resin (PMMA group); a light-cured urethane dimethacrylate (UDMA)-based resin (UDMA group); and a stereolithography (SLA) 3D-printed resin (SLA group). Surface roughness was measured before and after thermocycling (5,000 and 10,000 cycles between 5°C and 55°C) using a contact profilometer. Values were reported as mean (M) ±standard deviation (SD). The data was analyzed using repeated-measures or ordinary one-way analysis of variance (ANOVA), followed by Bonferroni-corrected post hoc tests (α = 0.0167). The UDMA group exhibited the lowest mean initial Ra values (0.078 ±0.020 μm). Thermocycling induced changes in surface roughness. In the PMMA group, a significant increase in mean Ra was observed after 5,000 cycles (0.103 ±0.028 μm before vs. 0.167 ±0.059 μm after; p = 0.0001) and after 10,000 cycles (0.107 ±0.024 μm before vs. 0.205 ±0.060 μm after; p < 0.0001). The increase in mean Ra following thermocycling was significantly greater in the PMMA group compared to the other groups (mean ΔRa after 5,000 cycles: 0.064 ±0.035 μm; after 10,000 cycles: 0.098 ±0.046 μm; all p < 0.0001). Materials used for the fabrication of intraoral appliances exhibit material-specific responses to thermal aging. The light-cured UDMA-based resin demonstrated superior surface integrity after aging, whereas conventional PMMA and the 3D-printed resin were more susceptible to surface alterations.

ABSTRACTAdditive manufacturing is transforming how microfluidic devices are prototyped and fabricated. Among various 3D printing methods, stereolithography (SLA) has become a dominant technique for microfluidics due to its high resolution and design flexibility, with widespread use in lab‐on‐a‐chip applications. However, intrinsic limitations of SLA printing, such as challenges related to multi‐material integration and microstructure fabrication in enclosed channels, continue to hinder the development of more complex microsystems, especially for analytical separation and tissue engineering applications. In this paper, we present a multiphase flow‐assisted in situ 3D printing method to address these challenges, developed based on our previously reported in situ 3D polymerization (IS‐3DP) concept. Our method utilizes an aqueous two‐phase system (ATPS) to generate sequential printing layers through controlled fluidic confinement and integrates an image‐guided alignment system to enable precise projection of printing patterns in microchannels. We demonstrate that viscosity tuning of the ATPS printing and blocking phases enables dynamic control of layer thickness, allowing customized and adaptive design of the 3D structure slicing. The image‐guided alignment system employs a homography transformation mechanism to map the projection and printing planes via image feedback, providing real‐time mask alignment with microchannel geometries. We characterize the mapping accuracy and projection fidelity and demonstrate the capability of this method by direct in‐channel fabrication of complex 3D microstructures such as pyramids, cuboids, bridge‐like void structures, as well as multi‐material patterns. We envision the multiphase flow‐assisted in situ 3D printing to offer a versatile tool for spatially controlled, high‐fidelity, and multi‐material microfabrication within confined microchannels in novel lab‐on‐a‐chip applications.

MR-guided radiotherapy enables real-time imaging and adaptive treatment but may introduce magnetic field effects that alter dose deposition. Accurate dose calculation in such settings requires detailed Monte Carlo (MC) modeling. To develop and validate a detailed MC model of the 0.5 T bi-planar Linac-MR with an integrated, custom-designed multileaf collimator (MLC) module in TOPAS. A MC Model of the 0.5T bi-planar Linac-MR with a 6MV FFF beam, commercialized as the Aurora-RT (MagnetTx Oncology Solutions, Canada), is developed in TOPAS. A custom 3D magnetic field vector map, tracking with gantry angle, is incorporated into this TOPAS model. An electron source is used for X-ray generation, and all components of the linac head from the target downward are modeled in detail. The MLCs are modeled from stereolithography (STL) design files and controlled via an empirically driven mechanism developed in this work. Water tank measured percent depth dose (PDD) curves and profiles (3 3 to 25 25 ) are compared to MC simulated data to optimize the electron source energy and radial distribution. Additionally, output factors are simulated and compared to measurements. MLC transmission at 10cm depth in solid water is simulated and measured using GAFChromic EBT3 film. MLC positioning accuracy is evaluated by comparing off-axis MLC-defined field profiles measured at 10cm depth in water. The MC model's dose calculation accuracy is further evaluated by comparing measured and simulated surface doses using EBT3 film, and PDDs in slab phantoms using parallel plate chambers. Surface dose is measured by placing films at the surface and 5cm depth in a solid water phantom. PDDs are measured and simulated in the following slab phantom configurations: polystyrene and polystyrene-bone-lung-polystyrene. A 5.5MeV electron source energy and a 1.3mm radial distribution (FWHM) provides the best match between measurement and MC. Simulated PDDs pass 1% 1mm gamma criteria at 100% compared to measurements for all fields investigated. Simulated profiles at various depths for all fields (3 3 to 25 25 ) score 96.7% in 2% 2mm compared to measurement. Evaluated output factors are in good agreement with measurement (within 1%) for all fields except 3 3 (within 1.5%). The 2% 2mm gamma pass-rates for MLC defined off-axis fields are 98%. The maximum mean Distance-To-Agreement (DTA) in the penumbra region (1% criteria) and mean dose difference in central region for inline and crossline profiles, are 1mm and 1%, respectively. MC simulated MLC transmission at central axis (0.28% - 0.29%) is in good agreement with measurement (0.28% - 0.44%). Film surface dose relative to Dmax is 74.4% in measurement and 73.6% in simulation. Lastly heterogeneous phantom PDDs passed 1% 1mm gamma criteria at % compared to measurement. The developed TOPAS MC model of the 0.5T Linac-MR demonstrates high accuracy for dose verification in magnetic fields. The MLC module, including its coordinate positioning mechanism, is fully validated for open aperture applications. This MC model provides a reliable framework for dose simulations in a magneticfield.

ABSTRACT The incorporation of lignocellulosic fillers into photopolymer matrices offers a promising route toward more sustainable additive manufacturing materials. However, their influence on stereolithography (SLA) processing and mechanical performance remains insufficiently understood. This study investigated the printability limits and mechanical behavior of beech wood (Fagus orientalis L.) particle – reinforced photopolymer composites produced via SLA. Beech wood particles were incorporated into an acrylate-based resin at 0%, 5%, 10%, and 15% by weight. Increasing wood content altered resin optical and rheological characteristics, resulting in UV light attenuation, reduced cure depth, and impaired interlayer adhesion. To compensate for these effects, bottom exposure times were increased from 40 s for the neat resin to 60 s and 70 s for the 5% and 10% formulations, respectively. Although specimens containing 15% wood particles could be fabricated, defects such as incomplete curing and delamination prevented mechanical testing. Tensile and compressive properties decreased systematically with increasing wood content due to weak interfacial bonding between hydrophilic wood particles and the hydrophobic photopolymer matrix, as well as microstructural heterogeneities. Among the investigated formulations, the composite containing 5% beech wood particles exhibited the most favorable balance between printability and mechanical performance. These results define filler-content thresholds for wood-filled SLA composites.

Background and Objectives: Academic point-of-care (POC) manufacturing enables the in-hospital design and production of patient-specific medical devices within certified environments, integrating clinical practice, engineering, and translational research. This model represents a new academic ecosystem that accelerates innovation while maintaining compliance with medical device regulations. Gregorio Marañón University Hospital has established one of the first ISO 13485-certified academic manufacturing facilities in Spain, providing on-site production of anatomical models, surgical guides, and custom implants for oral and maxillofacial surgery. This study presents a retrospective review of all devices produced between April 2017 and September 2025, analyzing their typology, materials, production parameters, and clinical applications. Materials and Methods: A descriptive, retrospective study was conducted on 442 3D-printed medical devices fabricated for oral and maxillofacial surgical cases. Recorded variables included device classification, indication, printing technology, material type, sterilization method, working and printing times, and clinical utility. Image segmentation and design were performed using 3D Slicer and Meshmixer. Manufacturing used fused deposition modeling (FDM) and stereolithography (SLA) technologies with PLA and biocompatible resin (Biomed Clear V1). Data were analyzed descriptively. Results: During the eight-year period, 442 devices were manufactured. Biomodels constituted the majority (approximately 68%), followed by surgical guides (20%) and patient-specific implants (7%). Trauma and oncology were the leading clinical indications, representing 45% and 33% of all devices, respectively. The orbital region was the most frequent anatomical site. FDM accounted for 63% of the printing technologies used, and PLA was the predominant material. The mean working time per device was 3.4 h and mean printing time 12.6 h. Most devices were applied to preoperative planning (59%) or intraoperative use (35%). Conclusions: Academic POC manufacturing offers a sustainable, clinically integrated model for translating digital workflows and additive manufacturing into daily surgical practice. The eight-year experience of Gregorio Marañón University Hospital demonstrates how academic production units can enhance surgical precision, accelerate innovation, and ensure regulatory compliance while promoting education and translational research in healthcare.