Compressive and flexural strength of provisional crown materials fabricated by conventional and 3D printing techniques: An in vitro study.

Evaluation of 3D printing and conventional manual techniques for crack sealing in asphalt pavements

Rapid antimicrobial-impregnated 3D-printed negative mould technique for PMMA cranioplasty in emergent management of syndrome of the trephined

Extrusion-based 3D printing of cross-scale porous bone scaffolds and their micro-topological structures for bone repair.

Microfluidic devices with ultra-fine features are critical for applications in biomedical diagnostics, chemical analysis, and lab-on-chip systems, but achieving high-resolution negative features with fast print times remains a significant challenge due to limitations in conventional 3D printing techniques. Motivated by the need for rapid fabrication of precise, compact microfluidic structures to enhance performance and miniaturization, we present an efficient multi-resolution 3D printing technique designed to fabricate microfluidic devices with exceptionally high-resolution negative features. For instance, we achieve fully enclosed channels with cross sections as small as 1.9 µm × 2.0 µm, a two-order-of-magnitude reduction in cross-sectional area compared to the 18 µm × 20 µm channels reported in our previous work (Gong et al., Lab Chip 17, 2899, 2017). Our method utilizes a dual-optical-engine approach comprising a Very High Resolution Optical Engine (VHROE) and a Main Optical Engine (MOE), each employing distinct pixel resolutions and LED wavelengths. The VHROE, with a pixel pitch of 0.75 µm and a 365 nm LED, delivers unparalleled resolution, while the MOE, with a pixel pitch of 15 µm and a 405 nm LED, ensures efficient coverage for larger areas up to 38.9 mm × 24.3 mm. Custom ultraviolet (UV) short-pass filters are used to tailor each LED spectrum, optimizing performance for each optical engine. Both engines are mounted on an XY stage to achieve multi-resolution imaging in the XY plane. Depth-wise (Z-axis) multi-resolution is achieved by formulating a photopolymerizable resin incorporating two UV absorbers possessing distinct absorption spectra such that the different light spectra from the VHROE and MOE encounter disparate levels of absorption, resulting in 1/e penetration depths of 2 µm and 20 µm, respectively. This enables true multi-resolution printing in all three dimensions. Our method balances speed and resolution by selectively deploying the VHROE for ultra-fine features and the MOE for bulk structures within a single 3D print. To demonstrate the versatility of this technique, we fabricated intricate microfluidic structures, including a triply-periodic minimal surface (TPMS) with 7 µm pores embedded within a 150 µm × 150 µm cross section enclosed channel, and an ultra-compact microfluidic mixer with a printed volume of only 0.017 mm³ (17 nL) and a print time of 21 minutes. These examples underscore the potential of our multi-resolution 3D printing method for advancing microfluidic device fabrication.

Sulphur, a major by-product of the oil and gas industry, has emerged as a promising construction material in both sulphur concrete (SC) and sulphur-extended asphalt (SEA) applications. This review examines the development, properties, and uses of these sulphur-based construction materials over a century by following PRISMA guidelines for systematic literature selection. A bibliometric analysis highlights a surge in research activity over the last two decades. The key advantages of sulphur concrete include rapid strength gain (achieving ~50 MPa within 1-2 days) and exceptional chemical durability in extreme environments. Sulphur-bound materials exhibit high corrosion resistance, low water permeability, and full recyclability upon reheating. Challenges such as thermal shrinkage-induced brittleness and temperature sensitivity have been mitigated by using polymer-modified sulphur and mix design optimisation. Sulphur-extended asphalts benefit from increased stiffness, stability, and cost savings compared to conventional mixtures. Enhanced performance has been observed at sulphur replacement levels of 20-40% in asphalt binders. The review also summarises mixed formulations, mechanical properties, durability metrics, and innovative applications ranging from acid-resistant industrial structures to sustainable pavement materials and even extraterrestrial construction. The environmental benefits, such as up to 40% GHG reduction and complete recyclability of sulphur-based concretes, align with circular economy goals. Future research directions include improving ductility, advancing 3D printing techniques, and field validation of long-term performance. Overall, sulphur by-products can be transformed into valuable construction materials that address waste management and infrastructure durability.

Diabetic wound management represents a substantial clinical challenge owing to the deteriorative tissue microenvironment including the excessive reactive oxygen species (ROS), persistent inflammation, and potential bacterial infection. To address these issues, herein, a hybrid hydrogel scaffold (SF@NP-Cur) capable of sequentially reprogramming the wound microenvironment was developed through microfluidic 3D printing technique for infected chronic wound healing. Such scaffold incorporates curcumin-loaded copper/iron bimetallic nanoparticles (NP-Cur), which confers not only the oxidase- and peroxidase-like activities for efficient ROS scavenging, but also enables the multimodal antibacterial behavior via copper release and photothermal effects of NP-Cur. Simultaneously, the release NP-Cur contribute to the pro-migration effect on fibroblasts, accelerating wound healing by promoting collagen deposition and angiogenesis. Furthermore, the loaded curcumin within NP-Cur enables the polarization of M1 macrophages toward the pro-regenerative M2 phenotype. Benefitting from these properties, such hydrogel scaffold potently accelerates the reconstruction of infected diabetic wounds by reprogramming the wound microenvironment indicated by the reduced ROS, attenuated inflammation, plentiful M2-type macrophages, and enhanced neovascularization. Collectively, this immunomodulatory scaffold represents a promising dressing for reconstruction of impaired chronic tissue environments, offering a robust therapeutic strategy for chronic wound repair and regeneration.

Advances in additive manufacturing have enabled the fabrication of denture bases using three-dimensional (3D) printing technology; however, the mechanical properties of the resulting materials, particularly impact strength, are highly influenced by post-processing parameters such as curing time. This experimental laboratory study aimed to evaluate the effect of different curing time variations on the impact strength of 3D-printed denture base resin and to compare its performance with that of heat-polymerized acrylic resin (HPAR). A post-test only control group design was employed, in which specimens were divided into four groups consisting of 3D-printed resin with curing times of 4.5, 5.0, and 5.5 seconds, and a control group fabricated from HPAR. The results demonstrated that the 3D-printed resin cured for 5.0 seconds exhibited the highest mean impact strength (1.56 ± 0.14 kJ/m²), followed by the 4.5-second group (1.47 ± 0.09 kJ/m²), while the lowest value was observed in the 5.5-second curing group (1.28 ± 0.23 kJ/m²). In contrast, the HPAR group showed substantially higher impact strength than all 3D-printed resin groups, with a mean value of 2.99 ± 0.97 kJ/m². These findings indicate that curing time optimization significantly affects the impact strength of 3D-printed denture base resin; nevertheless, heat-polymerized acrylic resin remains superior in terms of mechanical toughness for denture base applications

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 proof-of-concept study investigates the marginal and internal fit of lithium disilicate overlays produced using traditional and digital workflows. It also evaluates the influence of variables such as tooth preparation design and 3D printer type on the accuracy of the final restoration. Two extracted maxillary third molars were prepared with two different self-centering preparations (C1 and C2). Impressions were obtained with both conventional polyvinylsiloxane and digital intraoral scanners. Two different 3D printers were employed in this study. Working models were fabricated using conventional plaster and resin-based 3D printing techniques. Lithium disilicate overlays were then produced using both lost-waxing and 3D-printing workflows. All overlays were seated on their corresponding prepared tooth and scanned using micro-CT to assess the marginal and internal fit. The findings of this study revealed that restorations produced via 3D printing demonstrated comparable accuracy in marginal and internal fit to those fabricated through traditional heat-pressing techniques. The flat preparation design (C1) resulted in a superior marginal accuracy of the restorations. Although some differences in marginal accuracy were observed between the two printers tested in this study, these differences consistently remained below 100µm. Within the limitations of this proof-of-concept design, both traditional and digital workflows are capable of producing lithium disilicate overlays with clinically acceptable accuracy. This study suggests that 3D printing represents a viable and efficient alternative to conventional techniques for fabricating indirect restorations in clinical practice.

In this research paper, a detailed examination of the mechanical properties and morphologies of PLA and PBAT polymer blend materials which were produced through 3D printing techniques was conducted. The examination was completed using a PLA/PBAT/Joncryl blended material with a composition ratio of 77/20/3 wt% and manufactured through FDM techniques and an experimental design technique known as the Taguchi method to evaluate the effects of various manufacturing parameters on the mechanical characteristics of the material. This study investigates the mechanical and morphological performance of FDM-printed PLA/PBAT/Joncryl blend specimens using a Taguchi L9 design. A PLA/PBAT/Joncryl blend (77/20/3 wt%) was fabricated and printed by varying layer height (0.16–0.24 mm), printing temperature (190–210 °C), and infill density (50–100%). The optimal condition (0.16 mm, 210 °C, 100% infill) produced a maximum tensile strength of 41.20 N/mm² and elongation of 12.42%. ANOVA results confirmed infill density as the most significant parameter contributing 81.35% of the variance (P = 0.009). SEM revealed reduced voids and improved interlayer fusion at higher infill levels, while DMA showed higher storage modulus (~2200 MPa) for 100% infill specimens. The findings provide a process–structure–property relationship for optimizing biodegradable PLA/PBAT components for high-strength applications. This study illustrates that the infill % is the primary parameter that should be adjusted, while the layer height and printing temperature contribute but to a lesser extent to the improved performance of biodegradable PLA/PBAT/Joncryl blends.

Microneedles (MNs) are small devices that help to overcome the skin barrier and, thus, increase the effectiveness of transdermal drug delivery. This approach could be beneficial, especially for drugs characterised by low oral bioavailability, such as the antidepressant agomelatine (AGM), which is now only available on the market as an oral tablet. The aim of this study was to obtain agomelatine-loaded microneedle systems for potential use in the treatment of depression, using the 3D-printing methods. 3D-printing is an emerging technology enabling the manufacture of drug dosage forms or devices in a personalised, fast, and cost-efficient manner. Three 3D-printing techniques, different drug loading methods, and various shapes of microneedles were investigated along with the mechanical and physicochemical evaluation, release, stability, and toxicity studies of the obtained samples. Masked Stereolithography (MSLA) and PolyJet methods were successful in obtaining good-quality microneedle systems. Additionally, the MSLA method allowed for easy combining of the resin with the drug. The presence of the drug in the product was confirmed, and the drug release pattern depended on the loading method. Mechanical testing showed that Pyramid and Cone geometries were the most promising in puncture tests, and stability testing revealed the need for light- and moisture-resistant packaging. The formulations selected based on the obtained results will be further investigated on the way to create a transdermal alternative to agomelatine oral tablets and increase the effectiveness of depression treatment.

In response to the organ shortage and enhance surgical precision, 3D bioprinting has now become an innovative approach and technology that furnish practical challenges in the conventional medicine. Given the importance, the review is performed to understand clinical benefits and usage of this technology by using case studies on the 3D organ bioprinting implemented on the human live patients that implies about the various techniques of 3D organ printing. The study follows the standardized preferred reporting items for systematic review and meta-analysis structured (PRISMA-S) approach for the extraction of the relevant study from the databases by using the specific keywords such as “3D bioprint” and “Case study.” Only five pertinent case studies are selected which include pubic bone rebuilding, spinal defect repair, and liver transplantation in complex anatomical circumstances. It is noted from the studies that using 3D bioprint in complex cases reduced operative time by 30% and it enhanced anatomical visualization, surgical accuracy, and preoperative planning, but also emphasizes issues like expense, adaptability, and regulatory concerns, highlighting the necessity for further study and clinical use.

3D-microcontact printing (3D-µCP) technique combines the advantages of microcontact printing and microthermoforming for the fabrication of functional biomaterials with complexity closer to real tissue. Despite its unmet advantages in terms of complexity and processability in a single step, this technique is limited to the front side of the substrate. Considering the advantage of inherent topography patterns on the reverse side of the substrate, an additional degree of patterning can be envisioned. However, selective patterning on the reverse side is challenging due to the fragility of the cell culture on the front side. Herein, a technically simple scraping technique is presented in combination with 3D-µCP to generate 3D cell patterns on both the front and the reverse side of a micro thermoformed substrate. The technical advancement of 3D-µCP with the scraping technique offers a complex, multi-layered co-culture system that can be used to study cell-to-cell crosstalk at the microlevel with topographies similar to real tissue. Direct seeding of the third cell type on the scaffold expands cell type complexity, resulting in a tri-culture model. As a proof of concept, a triculture of EA.Hy 926 endothelial cells, HepG2 hepatoblastoma cells, and NIH3T3 fibroblasts are generated, mimicking the tumor microenvironment in the liver.

3D-printed conductive hydrogel scaffolds for bone regeneration: Electromechanical coupling, neurovascular integration, and immunomodulatory strategies.

This study offers a systematic review of the methodology surrounding the use of thermoplastics in three-dimensional (3D) printing for medical applications. Despite 3D printing not being extensively adopted for the creation of clinical medical devices due to safety and legal concerns, recent developments in materials, printing technology, and professional skills have broadened its clinical uses. The use of thermoplastics in 3D printing allows for the creation of economical components with diverse properties and potential applications. For example, literature consistently reports that while PLA-based structures typically exhibit tensile strengths in the range of 50–65 MPa, PEEK-based printed components achieve substantially higher strengths of 90–100 MPa, alongside superior fatigue resistance and long-term biocompatibility, making PEEK more suitable for load-bearing orthopedic applications. By employing design tactics such as thermoplastic layering, it is possible to reconcile competing demands, such as the mechanical strength and biological compatibility required for tissue structures. Consequently, this review summarizes the research efforts aimed at identifying appropriate thermoplastics, including polylactic acid (PLA), polypropylene (PP), polycarbonate (PC), polyurethane (PU), Acrylonitrile Butadiene Styrene (ABS), polyetheretherketone (PEEK), and polyvinyl alcohol (PVA), for the production of biomedical parts through 3D printing. It covers a range of produced items, including bones, high-quality prosthetics, intervertebral discs, medical devices, heart valves, and tissues containing blood vessels. Additionally, this review examines various 3D printing techniques, the challenges faced, and the future prospects for thermoplastic biomedical components.

The advancement of microfluidics has enabled a wide range of biochemical and biological applications, such as high-throughput drug testing or point-of-care diagnostics, and has also enabled dielectrophoretic applications. Dielectrophoresis (DEP) is based on the movement of polarizable particles in a non-uniform electric field. Implementing insulator-based dielectrophoresis (iDEP) in microfluidic systems has provided a new dimension for the precise manipulation of biomolecules. However, iDEP has been hampered due to the often cumbersome and expensive microfabrication methods that are required, especially for sub-µm analytes, including biomolecules, since extremely large electric field gradients are needed to achieve successful iDEP manipulation. In recent years, 3D printing has drawn attention in microfluidics, alleviating several issues with cleanroom-based fabrication methods. Among the 3D printing repertoire, two-photon polymerization (2PP) is a novel 3D printing technique that offers unique capabilities with unprecedented resolution compared to standard stereolithography. Here, we report the first iDEP-based manipulation of biomolecules, namely, λ-DNA and Phycocyanin, within a completely 3D-printed microfluidic device realized with 2PP printing. iDEP microfluidic devices with different post geometries were 3D-printed and developed with a gap resolution down to 2µm using theIP-S photoresist. Furthermore, sub-micrometer spatial resolution was achieved down to 800nm using theIP-Dip photoresist. Additionally, a numerical model was developed to determine the electric field gradients, DEP trapping force, and infer the associated polarizability and DEP characteristics of the analytes. This 3D printing technology may offer impactful potential for rapid prototyping of novel iDEP microdevices and the opportunity to explore iDEP for various biomolecular applications in the future.

3D printing, also known as additive manufacturing, has transformed drug delivery by enabling the development of complex, patient-specific dosage forms and implantable systems tailored to individual therapeutic needs. This review explores the convergence of 3D printing technologies with nanomaterials in the fabrication of advanced drug delivery systems and biomedical implants. Key 3D printing techniques, including Fused Deposition Modeling (FDM), Stereolithography (SLA), Direct Energy Deposition (DED), and electrospinning, are discussed alongside their material compatibilities, such as polymers, metals, ceramics, and composites. Nanomaterials-like dendrimers, liposomes, polymeric nanoparticles, carbon nanotubes, and exosomes-are critically examined for their roles in enhancing drug stability, targeted delivery, and controlled release. The paper highlights innovative drug delivery strategies, including polypills, gastro-floating tablets, and compartmentalized dosage systems, enabled by precise 3D printing. Additionally, recent advancements in 3D-printed drugeluting implants for localized therapy in cancer and infectious diseases are presented. These systems demonstrate prolonged release profiles, biocompatibility, and mechanical properties resembling those of human tissue. Despite scaling and regulatory challenges, the future of this technology lies in the integration of smart materials, surface-modified nanoparticles, and AI-assisted design, paving the way for decentralized, personalized, and sustainable medical solutions.

ABSTRACT Screw-based material extrusion is a prominent 3D printing technology that finds applications across various industrial sectors, including aerospace, architecture, and medicine. However, using high-viscosity and high-solid materials often leads to flow restrictions and nozzle blockages during the extrusion process. This results in suboptimal moulding quality or even complete failure, which has emerged as a significant bottleneck hindering the advancement of extrusion-based 3D printing. To solve this problem, this paper combines the traditional screw extrusion with ultrasonic vibration and proposes a novel ultrasonic assisted 3D Printing technique. Firstly, a 3D printing device equipped with a screw ultrasonic vibration unit was designed and built. Then, computational fluid dynamics (CFD) simulations and experiments were carried out with high solid content clay to investigate the effectiveness of this technology. The results reveal that ultrasonic vibration enhances the performance of traditional screw-based 3D printing significantly, including higher flow rate, fewer surface defects, and better printability with smaller nozzle sizes.

Bone and cartilage defects resulting from trauma, degenerative diseases, or congenital malformations remain a major clinical challenge due to the limited intrinsic healing capacity of these tissues often leads to unsatisfactory outcomes. Piezoelectric biomaterials, which are capable of generating localized electrical signals under mechanical stimulation, have attracted considerable attention as they could mimic the electromechanical microenvironment of native tissues and modulate key cellular processes. However, conventional fabrication strategies were usually failed to meet the personalized requirements of bone and cartilage regeneration. Three-dimensional (3D) printing offers powerful tools for producing patient-specific scaffolds with complex architectures and controlled functionality. In this review, we firstly introduced the piezoelectric properties of the natural bone and cartilage tissue, and then discussed the characteristics of piezoelectric materials in regenerative medicine, with particular emphasis on the advantages and limitations of usage of 3D printing techniques in the fabrication of the piezoelectric biomaterials. Finally, we summarized the recent advances in 3D-printed piezoelectric scaffolds for bone and cartilage regeneration. Consequently, this review highlights the significant potential and practical value of 3D-printed piezoelectric scaffolds as the next generation of osteochondral implants.