Digital Light Processing of Thermoresponsive Hydrogels from Polyproline-Based Star Polypeptides.

The first report of star poly(L-proline) crosslinkers is disclosed for digital light processing 3D printing of thermoresponsive hydrogels. Through chain end functionalization of star poly(L-proline)s with methacryloyl groups, access to high-resolution defined 3D hydrogel structures via digital light processing is achieved through photoinitiated free radical polymerization. Changing the poly(L-proline) molecular weight has a direct influence on both thermoresponsiveness and printability, while shape-morphing behavior can be induced thermally.

High-Precision Printing of Cermets by Collapsable Matrix Assisted Digital Light Processing.

Shaping hard and brittle materials, e.g. cermets, at micrometer resolution has long been known challenging for both mechanical machining and high energy beam based additive manufacturing. Digital light processing (DLP), which features great printing quality and decent precision, unfortunately lacks capability to deal with the popular slurry-typed cermet precursor due to the tremendous optical absorption by its particles. Here, an innovative protocol based on a versatile collapsable matrix is devised to allow high-precision printing of WC-Co cermets on DLP platform. By tuning the external environment, this matrix attenuates composite powders to facilitate photopolymerization at the printing stage, and shrinks to condense green parts prior to thermal sintering. The as-obtained samples by collapsable matrix assisted DLP can reach a relative density of ≈90%, a record-breaking resolution of ≈10 µm, and a microhardness of up to 14.5 GPa. Complex delicate structures, including school emblem, honeycomb, and micro-drill can be directly fabricated, which has never been achieved before. Impressively, the as-obtained micro-drill is able to be directly used in drilling tasks. The above strategy represents a great progress in DLP by enabling shaping strong light attenuating materials at high resolution. Such advantages are ideal for the next generation ceramic-metal composite additive manufacturing.

4D-Printable Photocrosslinkable Polyurethane-Based Inks for Tissue Scaffold and Actuator Applications.

4D printing recently emerges as an exciting evolution of conventional 3D printing, where a printed construct can quickly transform in response to a specific stimulus to switch between a temporary variable state and an original state. In this work, a photocrosslinkable polyethylene-glycol polyurethane ink is synthesized for light-assisted 4D printing of smart materials. The molecular weight distribution of the ink monomers is tunable by adjusting the copolymerization reaction time. Digital light processing (DLP) technique is used to program a differential swelling response in the printed constructs after humidity variation. Bioactive microparticles are embedded into the ink and the improvement of biocompatibility of the printed constructs is demonstrated for tissue engineering applications. Cell studies reveal above 90% viability in 1 week and ≈50% biodegradability after 4 weeks. Self-folding capillary scaffolds, dynamic grippers, and film actuators are made and activated in a humid environment. The approach offers a versatile platform for the fabrication of complex constructs. The ink can be used in tissue engineering and actuator applications, making the ink a promising avenue for future research.

Printing of In Situ Functionalized Mesoporous Silica with Digital Light Processing for Combinatorial Sensing.

Combinatorial sensing is especially important in the context of modern drug development to enable fast screening of large data sets. Mesoporous silica materials offer high surface area and a wide range of functionalization possibilities. By adding structural control, the combination of structural and functional control along all length scales opens a new pathway that permits larger amounts of analytes being tested simultaneously for complex sensing tasks. This study presents a fast and simple way to produce mesoporous silica in various shapes and sizes between 0.27-6 mm by using light-induced sol-gel chemistry and digital light processing (DLP). Shape-selective functionalization of mesoporous silica is successfully carried out either after printing using organosilanes or in situ while printing through the use of functional mesopore template for the in situ functionalization approach. Shape-selective adsorption of dyes is shown as a demonstrator toward shape selective screening of potential analytes.

Ultra-Fast Fabrication of Mechanical-Water-Responsive Color-Changing Photonic Crystals Elastomers and 3D Complex Devices.

The traditional fabrication of opal-structured photonic crystals is constrained by the rate of solvent evaporation, a process that is not only time-consuming but also labor-intensive. This study introduces a paradigm shift by incorporating silica nanoparticles (SiNPs) with high zeta potentials and hydrogen bonding capabilities into an elastomeric matrix, resulting in a novel non-close-packed structure. This innovation circumvents the limitations of conventional methods by enabling the rapid formation of photonic inks (PI) into vibrant and luminous photonic elastomers (PEs) within seconds. These PEs demonstrate remarkable mechanochromic properties, exhibiting dynamic color changes across the visible spectrum in response to tensile and compressive deformations. Furthermore, the presence of hydroxyl groups endows the PEs with superior water-responsiveness, which can be finely tuned through the ink formulation. The elimination of solvent evaporation dependency facilitates the fabrication of macroscopic photonic crystal devices with complex geometries using digital light processing (DLP)-based 3D printing. This approach ensures exceptional optical performance and high customization potential. The resulting PEs hold significant promise for applications in smart wearables, soft robotics, and advanced human-machine interface technologies.

Influence of Si3N4 fillers and pyrolysis profile on the microstructure of additively manufactured silicon carbonitride ceramics derived from polyvinylsilazane.

In this work, various methods were used to improve the printability of a photocurable polyvinylsilazane resin filled with silicon nitride particles for digital light processing. The developed resin was used as a preceramic polymer for polymer-to-ceramic conversion. The pyrolysis-induced structural changes of the additively manufactured objects were evaluated by comparing samples with different thicknesses, filler amounts and heating profiles. The printed green body retained its original geometry better and showed fewer cracks due to the addition of silicon nitride particles to the resin. Based on the thermally induced changes in a polyvinylsilazane resin system, a customized heating profile for the pyrolysis process was developed, which contributed to the reduction of pores and cracks while the average pyrolysis heating rate remained relatively high. This work provides insight into the pyrolysis of additively manufactured preceramic polymer green bodies and highlights various strategies for additive manufacturing of polymer-derived ceramics.

The presented work systematically demonstrates the microstructural optimization of additively manufactured polymer-derived ceramics through combination of high refractive index filler inclusion and pyrolysis procedure customization.

Highly Efficient All-3D-Printed Electrolyzer toward Ultrastable Water Electrolysis.

The practical application of electrochemical water splitting has been plagued by the sluggish kinetics of bubble generation and the slow escape of bubbles which block reaction surfaces at high current densities. Here, 3D-printed Ni (3DP Ni) electrodes with a rationally designed periodic structure and surface chemistry are reported, where the macroscopic ordered pores allow fast bubble evolution and emission, while the microporosity ensures a high electrochemically active surface area (ECSA). When they are further loaded with MoNi4 and NiFe layered double hydroxide active materials, the 3D electrodes deliver 500 mA cm-2 at an overpotential of 104 mV for the hydrogen evolution reaction (HER) and 310 mV for the oxygen evolution reaction (OER), respectively. An all-3D-printed alkaline electrolyzer (including electrodes, membrane, and cell) delivers 500 mA cm-2 at a remarkable voltage of 1.63 V with no noticeable performance decay after 1000 h. Such a tailored bubble trajectory demonstrates feasible solutions for future large-scale clean energy production.

Comparison of shock absorption capacities of three types of mouthguards: A comparative in vitro study.

BACKGROUND/AIM: 3D printing processes can be used to manufacture custom-made mouthguards for sports activities. Few studies have compared the impact performance of industrial-created mouthguards with that of custom-made mouthguards manufactured by thermoforming or 3D printing. The objective of this in vitro study was to compare the shock absorption capacities of custom-made mouthguards manufactured by 3D printing with industrial mouthguards and thermoformed ethylene vinyl acetate (EVA) mouthguards. MATERIALS AND METHODS: For each type of mouthguard, eight samples were produced. 3D-printed mouthguards were manufactured using digital light processing technology. Each mouthguard was subjected to an impact performance test defined by the standard AFNOR XP S72-427, which evaluate maximum deceleration and force transmitted during impact. The thickness of each mouthguard before and after a series of five impacts was measured at the impacted inter-incisal area. RESULTS: The mean maximum decelerations during impact ranged from 129 to 189 g for industrial mouthguards, 287 to 425 g for thermoformed EVA mouthguards, and 277 to 302 g for 3D-printed mouthguards. The mean reduction in mouthguard thickness at the impact zone after five tests was 1.2 mm for industrial mouthguards, 0.6 mm for 3D-printed mouthguards, and 2.2 mm for thermoformed EVA mouthguards. CONCLUSIONS: Custom-made 3D printed mouthguards showed slightly better shock absorption ability than thermoformed mouthguards with respect to the indicator proposed in XP S72-427. They seemed to combine the practical advantages of thermoformed mouthguards in sports with better shock absorption capacity and lower cost. Furthermore, they had the least thickness variation during the test, and their shock absorption capacity was the least affected by repeated mechanical tests. Other types of 3D-printing resin materials that will become available must continue to be tested for shock absorption to provide the best protection to users at low cost.

Pharmaceutical applications and requirements of resins for printing by digital light processing (DLP).

The digital light processing (DLP) printer has proven to be effective in biomedical and pharmaceutical applications, as its printing method does not induce shear and a strong temperature on the resin. In addition, the DLP printer has good resolution and print quality, which makes it possible to print complex structures with a customized shape, being used for various purposes ranging from jewelry application to biomedical and pharmaceutical areas. The big disadvantage of DLP is the lack of a biocompatible and non-toxic resin on the market. To overcome this limitation, an ideal resin for biomedical and pharmaceutical use is needed. The resin must have appropriate properties, so that the desired format is printed when with a determined wavelength is applied. Thus, the aim of this work is to bring the basic characteristics of the resins used by this printing method and the minimum requirements to start printing by DLP for pharmaceutical and biomedical applications. The DLP method has proven to be effective in obtaining pharmaceutical devices such as drug delivery systems. Furthermore, this technology allows the printing of devices of ideal size, shape and dosage, providing the patient with personalized treatment.

Depth of reading within the gingival sulcus of seven intraoral scanners: an in vitro study.

AIM: The present in vitro study aimed to evaluate the depth of reading of intraoral scanners (IOSs) within the gingival sulcus. MATERIALS AND METHODS: A knife-edge preparation for a full crown was performed on a Frasaco model. The gingival sulcus of the scanned model was modified using a dedicated software program (Model Creator, exocad DentalCAD 2.4 Plovdiv) by setting the apical width (AW), coronal width (CW), and gingival sulcus depth (D). Two dental models with different gingival sulcus depths (1 or 2 mm) were printed using the digital light processing (DLP) technique. Each model was scanned 10 times. Seven different IOSs were used: Emerald, Trios 3, Carestream 3600, Dental Wings DWIO, CondorScan, True Definition Scanner (TDS), and Cerec Omnicam. Measurements of D values were performed using 3Shape 3D viewer software. The normality of the data distribution was evaluated using the Shapiro-Wilk test (P < 0.05). The nonparametric Levene's test was used to check for homoscedasticity. The data were statistically analyzed using the Kruskal-Wallis test (α = 0.05) and the Nemenyi test. RESULTS: All IOSs were able to read within the 1-mm-deep gingival sulcus, albeit with some statistically significant differences (P < 0.001). TDS and Trios 3 were able to read within the 2-mm-deep gingival sulcus (P < 0.001). CONCLUSIONS: The depth of reading of different IOSs can vary significantly. In the model with a 2-mm gingival sulcus, even in the absence of oral fluids, the depth of reading was incomplete, suggesting that deep preparations into the gingival sulcus are difficult to detect with IOSs.

Low-Temperature Resistant Stretchable Micro-Supercapacitor Based on 3D Printed Octet-Truss Design.

Recently, stretchable micro-supercapacitors (MSCs) that can be easily integrated into electronic devices have attracted research and industrial attentions. In this work, three-dimensional (3D) stretchable MSCs with an octet-truss electrode (OTE) design have been demonstrated by a rapid digital light processing (DLP) process. The 3D-printed electrode structure is beneficial for electrode-electrolyte interface formation and consequently increases the number of ions adsorbed on the electrode surface. The designed MSCs can achieve a high capacitance as ≈74.76 mF cm-3 under 1 mA cm-3 at room temperature even under a high mechanical deformation, and can achieve 19.53 mF cm-3 under 0.1 mA cm-3 at a low temperature (-30 °C). Moreover, finite element analysis (FEA) reveals the OTE structure provides 8 times more contact area per unit volume at the electrode-electrolyte interface compared to the traditional interdigital electrode (IDE). This work combines structural design and 3D printing techniques, which provides new insights into highly stretchable MSCs for next-generation electronic devices.

A Data-Driven Approach to Complex Voxel Predictions in Grayscale Digital Light Processing Additive Manufacturing Using U-Nets and Generative Adversarial Networks.

Data-driven U-net machine learning (ML) models, including the pix2pix conditional generative adversarial network (cGAN), are shown to predict 3D printed voxel geometry in digital light processing (DLP) additive manufacturing. A confocal microscopy-based workflow allows for the high-throughput acquisition of data on thousands of voxel interactions arising from randomly gray-scaled digital photomasks. Validation between prints and predictions shows accurate predictions with sub-pixel scale resolution. The trained cGAN performs virtual DLP experiments such as feature size-dependent cure depth, anti-aliasing, and sub-pixel geometry control. The pix2pix model is also applicable to larger masks than it is trained on. To this end, the model can qualitatively inform layer-scale and voxel-scale print failures in real 3D-printed parts. Overall, machine learning models and the data-driven methodology, exemplified by U-nets and cGANs, show considerable promise for predicting and correcting photomasks to achieve increased precision in DLP additive manufacturing.

Digital Light Processing-3D Printing of Thermoset Materials with High Biodegradability from Amino Acid-Derived Acrylamide Monomers.

Six acrylamide resins, derived from l-phenylalanine and l-leucine, are designed for application in digital light processing (DLP) printers to obtain biodegradable thermoset polymers. The acrylamide copolymers are prepared under light irradiation at 405 nm and thermal post-curing processes. Low molecular weight poly(ethylene glycol)diacrylate (PEGDA) and N,N-dimethylacrylamide (DMAM), both liquid resins, are used as co-monomers and diluents for the amino acid-derived acrylamide solubilization. The presence of two phenylalanine units and two ester groups in the acrylamide monomer accuses a fast degradation rate in hydrolytic medium in 90 days. The residual products leached in the aqueous media prove to be non-cytotoxic, when 3D-printed samples are cultured with osteoblast cells (MG63), which represents an advantage for the safe disposal of printer waste materials. The scaled-up pieces derived from l-phenylalanine and diethylene glycol, as amino acid-derived acrylamide (named compound C), PEGDA and DMAM, present high dimensional stability after DLP printing of complex structures used as testing samples. Layers of 50 µm of thickness are well cohesive having isotropic behavior, as demonstrated with tensile-strain measurements performed in X-Y-Z (plane) directions. The compound C, which contains phenylalanine amino acid, reveals a promising potential to replace non-biodegradable acrylate polymers used in prototyping systems.

Solid-State Crosslinkable, Shape-Memory Polyesters Serving Tissue Engineering.

Acrylate-endcapped urethane-based precursors constituting a poly(D,L-lactide)/poly(ε-caprolactone) (PDLLA/PCL) random copolymer backbone are synthesized with linear and star-shaped architectures and various molar masses. It is shown that the glass transition and thus the actuation temperature could be tuned by varying the monomer content (0-8 wt% ε-caprolactone, Tg,crosslinked = 10-42 °C) in the polymers. The resulting polymers are analyzed for their physico-chemical properties and viscoelastic behavior (G'max = 9.6-750 kPa). The obtained polymers are subsequently crosslinked and their shape-memory properties are found to be excellent (Rr = 88-100%, Rf = 78-99.5%). Moreover, their potential toward processing via various additive manufacturing techniques (digital light processing, two-photon polymerization and direct powder extrusion) is evidenced with retention of their shape-memory effect. Additionally, all polymers are found to be biocompatible in direct contact in vitro cell assays using primary human foreskin fibroblasts (HFFs) through MTS assay (up to ≈100% metabolic activity relative to TCP) and live/dead staining (>70% viability).

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil.

Adulterations of olive oil are performed by adding seed oils to this high-quality product, which are cheaper than olive oils. Food safety controls have been established by the European Union to avoid these episodes. Most of these methodologies require expensive equipment, time-consuming procedures, and expert personnel to execute. Near-infrared spectroscopy (NIRS) technology has many applications in the food processing industry. It analyzes food safety and quality parameters along the food chain. Using principal component analysis (PCA), the differences and similarities between olive oil and seed oils (sesame, sunflower, and flax oil) have been evaluated. To quantify the percentage of adulterated seed oil in olive oils, partial least squares (PLS) have been employed. A total of 96 samples of olive oil adulterated with seed oils were prepared. These samples were used to build a spectra library covering various mixtures containing seed oils and olive oil contents. Eighteen chemometric models were developed by combining the first and second derivatives with Standard Normal Variable (SNV) for scatter correction to classify and quantify seed oil adulteration and percentage. The results obtained for all seed oils show excellent coefficients of determination for calibration higher than 0.80. Because the instrumental aspects are not generally sufficiently addressed in the articles, we include a specific section on some key aspects of developing a high-performance and cost-effective NIR spectroscopy solution for fraud detection in olive oil. First, spectroscopy architectures are introduced, especially the Texas Instruments Digital Light Processing (DLP) technology for spectroscopy that has been used in this work. These results demonstrate that the portable prototype can be used as an effective tool to detect food fraud in liquid samples.

Color stability, surface roughness and flexural strength of additively manufactured and milled interim restorative materials after aging.

To evaluate the effect of two different additive manufacturing technologies on the color stability, surface roughness and biaxial flexural strength of interim restorative materials after thermal aging. Disk-shaped specimens were manufactured via two types of vat polymerization methods [Stereo-lithography (SLA) and digital light processing (DLP)] and milling technology (n = 16). CIELab color coordinates and surface roughness were measured before and after thermal cycling. Then biaxial flexural strength tests were performed using a universal testing machine. The data were analyzed by Kruskal-Wallis, one-way ANOVA, and Tamhane and Tukey HSD tests (α < 0.05). There was no significant difference among ΔE values of all study groups (p = 0.191). The milled group showed a higher initial surface roughness value (p < 0.05), while there was no significant difference among the other groups after aging (p = 0.213). DLP had significantly lower flexural strength values than SLA and Milled (p = 0.000). After aging, SLA and DLP were similar to milling method, in terms of color stability and surface roughness. However, milling had an adverse effect on the initial surface roughness. The SLA and milled groups had better mechanical properties than the DLP group.

Generation of a Perfusable 3D Lung Cancer Model by Digital Light Processing.

Lung cancer still has one of the highest morbidity and mortality rates among all types of cancer. Its incidence continues to increase, especially in developing countries. Although the medical field has witnessed the development of targeted therapies, new treatment options need to be developed urgently. For the discovery of new drugs, human cancer models are required to study drug efficiency in a relevant setting. Here, we report the generation of a non-small cell lung cancer model with a perfusion system. The bioprinted model was produced by digital light processing (DLP). This technique has the advantage of including simulated human blood vessels, and its simple assembly and maintenance allow for easy testing of drug candidates. In a proof-of-concept study, we applied gemcitabine and determined the IC50 values in the 3D models and 2D monolayer cultures and compared the response of the model under static and dynamic cultivation by perfusion. As the drug must penetrate the hydrogel to reach the cells, the IC50 value was three orders of magnitude higher for bioprinted constructs than for 2D cell cultures. Compared to static cultivation, the viability of cells in the bioprinted 3D model was significantly increased by approximately 60% in the perfusion system. Dynamic cultivation also enhanced the cytotoxicity of the tested drug, and the drug-mediated apoptosis was increased with a fourfold higher fraction of cells with a signal for the apoptosis marker caspase-3 and a sixfold higher fraction of cells positive for PARP-1. Altogether, this easily reproducible cancer model can be used for initial testing of the cytotoxicity of new anticancer substances. For subsequent in-depth characterization of candidate drugs, further improvements will be necessary, such as the generation of a multi-cell type lung cancer model and the lining of vascular structures with endothelial cells.

Wear behaviour of lithography ceramic manufactured dental zirconia.

OBJECTIVE: The study aims to evaluate the wear surface using 3D surface roughness and other material characterization of zirconia fabricated using photopolymerization based Lithography-based Ceramic Manufacturing (LCM). METHOD: LCM technology was used to fabricate zirconia specimens of size 10 × 10 × 2mm3. Scanning Electron Microscope, 3D-profilometer, X-ray Diffraction, and hardness test characterized the samples before and after wear and Coefficient of friction (COF) was monitored. RESULT: The COF was around 0.7 and did not differ much between the horizontally and vertically printed specimens. However, the surface roughness after wear for horizontally printed specimen was 0.567 ± 0.139 µm, while that for vertically printed specimen was 0.379 ± 0.080 µm. The reduced valley depth and the dale void volume were low for the vertically printed zirconia specimen, indicating lesser voids and low fluid retention. In addition, it was observed that the hardness value of the vertically printed sample was better. The scanning electron microscopic images and 3D surface profiles of the zirconia specimens depicted the surface topography and revealed the wear track. CONCLUSION: The study shows that zirconia fabricated using LCM technology possesses surface roughness of about 0.5 µm with no machining scars that are usually associated with CAD/CAM dentistry and also indicating agreement with clinically acceptable values for minimal surface roughness of dental restorations. Dental restorations using LCM fabricated zirconia redues the requirement of post-processing work flow that is part of CAD/CAM dentistry.

Comparison of denture base adaptation between additive and conventional fabrication techniques.

PURPOSE: This in vitro study compared the adaptation of denture bases fabricated by injection molding (IM), compression molding (CM), liquid crystal display (LCD), and digital light processing (DLP) techniques. MATERIAL AND METHODS: A definitive maxillary cast was duplicated using a silicone mold to create 40 gypsum casts that were laser scanned before any fabrication procedures were initiated. For the DLP and LCD groups, 20 denture bases (10 in each group) were virtually designed and manufactured referring to the digitalized data. For the CM and IM groups, 20 denture bases (10 in each group) were molded using gypsum models. A total of 40 gypsum models and their corresponding denture bases were scanned. The scanned intaglio surface of each denture base was superimposed on the scanned reference cast to compare the degree of tissue surface adaptation. The three-dimensional surface deviations of the total intaglio surface, denture border apex, palatal vault, and crest of the ridge were evaluated on the basis of the best fit algorithm technique using inspection software. The data were statistically analyzed using one-way ANOVA and Tukey's multiple comparison test (α = 0.05). RESULTS: According to the superimposing results, for the total intaglio surface, the lowest deviation was present on the injection-molded group and the highest deviation occurred on the LCD group. For the palatal vault, the lowest deviation was present on the DLP group and the highest deviation occurred in the compression molded group. For the crest of the ridge, the lowest deviation was present in the injection-molded group and the highest deviation occurred in the LCD group. For the denture border apex, the lowest deviation was present in the DLP group and the highest deviation occurred in the LCD group. CONCLUSIONS: Maxillary denture bases fabricated using DLP and IM techniques showed higher surface adaptation than the bases fabricated using LCD and CM techniques. Among the conventional techniques, higher compatible dentures can be produced with IM; among the additive techniques, higher compatible dentures can be produced with DLP.

The effects of additive manufacturing technologies and finish line designs on the trueness and dimensional stability of 3D-printed dies.

PURPOSE: To evaluate the effects of 5 manufacturing technologies and 2 finish line designs on the trueness and dimensional stability of 3D-printed definitive dies at finish line regions under different storage conditions and time. MATERIAL AND METHODS: Preparation of light chamfer and round shoulder finish lines were adopted individually on two mandibular first molar typodont teeth and digitalized as standard tessellation language (STL) files. A total of 240 samples (192 AM definitive dies and 48 definitive conventional stone dies) in 20 groups (n = 12) were manufactured based on 2 finishing line designs (chamfer and shoulder), 5 manufacturing technologies (4 additively manufactured technologies and conventional stone die), and 2 storage conditions (light exposure and dark). The 4 additively manufactured (AM) technologies include a DLP 3D-printer, an economic LED 3D-printer, a CLIP 3D-printer, and an SLA 3D-printer. All the study samples were distributed into two storage conditions. Subsequently, samples were digitalized to STL files at 3 different time points (within 36 hours, 1-month, and 3-months). A surface matching software was used to superimpose the sample STL files onto the corresponding original STL files with the best-fit alignment function. The trueness of each printed and stone definitive dies and their dimensional stabilities were measured by the root mean square (RMS, in mm). A linear mixed-effects model was used to test the effects of the finish line design, manufacturing technology, storage condition, and storage time on RMS values (α = 0.05). RESULTS: While finish line designs had no significant effects [F(1, 220) = 0.85, p < 0.358], the manufacturing technologies [F(3, 220) = 33.02, p < 0.001], storage condition [F(1, 220) = 4.11, p = 0.044], and storage time F(2, 440) = 10.37, p < 0.001] affected the trueness and dimensional stability of 3D-printed dies at finish line regions. No significant interactions were found among the 4 factors. For the manufacturing technologies, Type IV stone groups and LCD 3D-printer groups had significantly higher RMS values than the other 3 printers (p < 0.001) with no significant differences between Type IV stone and LCD 3D-printer groups (p = 0.577). DLP 3D-printer groups had higher RMS values than both SLA 3D-printer groups and CLIP 3D-printer groups (p < 0.001). There were no significant differences between SLA 3D-printer groups and CLIP 3D-printer groups, p = 0.671. For the effects of storage conditions, RMS values were significantly higher in the groups stored with the direct light exposure than the ones stored in the dark, p = 0.044. In terms of the effects of storage time, the RMS values were significantly higher after 1-month storage, p = 0.002; and 3-month storage, p < 0.001, than the ones at the immediate postmanufacturing stage. However, the RMS values after 1-month and 3-month storage were not significantly different from each other (p = 0.169). CONCLUSIONS: Manufacturing technologies, storage conditions, and storage time significantly affected the trueness and dimensional stability of 3D-printed dies at finish line regions, while finish line designs had no significant effects. Among the AM technologies tested, all have produced either comparable or truer 3D-printed dies than the Type IV dental stone dies, and the CLIP and SLA 3D-printers produced the best outcomes. 3D-printed dies showed significant distortion after 1-month and 3-months storage, especially under light exposure storage conditions. These findings may negate the clinical need to preserve 3D-printed dies, and digital data should be preserved instead.