Search Results (53)

Nickel-titanium (NiTi) alloys are attractive for functional and biomedical applications due to their shape memory effect, superelasticity, and favorable corrosion resistance and biocompatibility. In this work, the influence of strut size on the compressive response of laser-based powder bed fusion (PBF-LB/M) fabricated NiTi ortho-octahedral porous scaffolds was systematically investigated using combined experiments and finite element simulations. Four scaffold designs with identical unit-cell size (2 mm) but different strut sizes (280, 320, 360, and 400 μm) were fabricated, and their forming quality and deformation behaviors were examined. The as-built scaffolds exhibited high geometric fidelity to the CAD models and stable manufacturability across the investigated parameter range. Quasi-static compression tests revealed a typical three-stage response (linear-elastic regime, plateau/collapse regime, and densification), with both elastic modulus and compressive strength increasing markedly with strut size. Specifically, the modulus increased from 1.17 to 4.28 GPa and the compressive strength increased from 155 to 564 MPa as the strut size increased from 280 to 400 μm. A pronounced oscillatory plateau was observed for the 280 μm scaffolds, indicating progressive layer-by-layer collapse, whereas larger struts promoted a shear-band-dominated failure mode characterized by an approximately 45° fracture zone. Explicit quasi-static simulations reproduced the experimentally observed collapse sequence and demonstrated that stress preferentially concentrates at nodal junctions, with load transfer dominated by struts aligned with the loading direction. The agreement between experiments and simulations confirms the predictive capability of the proposed modeling framework and provides mechanistic insights into geometry-controlled failure. These findings establish a structure-property-failure relationship for PBF-LB/M-fabricated NiTi octahedral scaffolds and offer practical guidance for tailoring stiffness, strength, and collapse mode through strut-size design. Full article

Although blood–brain barrier (BBB) models are of great value in investigating neurological diseases, the structural complexity and intricate function based on cell–cell interactions of the BBB bring various limitations to the applications of existing models. In this study, a novel BBB micro-organoid model was established by culturing neurovascular unit (NVU) cells on a decellularized squid mantle scaffold (DSMS) film to reconstitute a more authentic and reliable NVU microenvironment for in vitro research. The DSMS applied was obtained from squid mantle scaffolds via decellularization, followed by defatting, and showed good biocompatibility with no cytotoxicity. The DSMS film was finally prepared by lyophilization. The lyophilized film exhibited a void ratio and pore size suitable for the adhesion and growth of endothelial cells (hCMEC/D3) and astrocytes (hACs), which led to the formation of a BBB-like spatial structure. The BBB micro-organoid model exhibited functional barrier properties, including an effective transendothelial electrical resistance (TEER) of approximately 230 Ω/cm², restricted permeability to macromolecules—with apparent permeability coefficients (Papp) of 6.3 × 10⁻⁷ cm/s for 10 kDa and 2.7 × 10⁻⁷ cm/s for 70 kDa FITC–dextran—and expression of tight junctional complex (TJC) proteins such as vascular endothelial cadherin (VE-cad) and Zonula Occludens-1 (ZO-1). Furthermore, low-density lipoprotein receptor-related protein 1 (LRP1), a key receptor stably expressed in these two NVU cell types, was utilized as a critical indicator to assess the integrity of the BBB micro-organ model and its responsiveness to pathophysiological stimuli, particularly under thrombotic conditions. This study not only validates the feasibility of constructing a functionally competent BBB micro-organ model using DSMS films integrated with NVU cells but also provides a promising in vitro platform for subsequent studies on the BBB-related pathological mechanisms and the evaluation of drug permeability across the BBB. Full article

Background: The aim of this experimental pilot study was to evaluate the effect of pore volume and material composition on bone ingrowth into a resorbable poly-L-lactide-CaCO₃/CaP scaffold. Methods: Cylindric scaffolds of 7 mm diameter and 5 mm height and two different degrees of porosity were produced using selective laser sintering of poly-L-lactide-powder containing 24% CaCO₃ spherulites with and without surface modification with 4% CaP. Six minipigs received the four types of macroporous cylindrical scaffolds, inserted press fit into trephine defects of the tibial metaphyses, and left to heal for 4 and 13 weeks in three animals each. The specimens were evaluated using µCT for pore volume fill, and histomorphometry for bone formation and immunohistochemistry for expression of osteocalcin. Results: After 4 weeks, newly formed bone ranged from 2.73 mm² to 5.28 mm² mean total area. Mean pore volume fill varied between 12.25% and 20.35% and the average level of osteocalcin expression ranged from 2.49 mm² to 4.48 mm² mean total area. No significant differences were found between the different scaffolds. After 13 weeks, bone formation and pore fill volume had significantly increased in all scaffold groups up to a mean value of 14.79 mm² and 96.04%, respectively. Again, differences between the groups were not significant. Conclusions: The tested SLS produced scaffolds allowed for bone ingrowth, almost completely filling the pore volume after 13 weeks. Newly formed bone was in direct contact with the scaffold walls. Differences in pore volume did not account for significant differences in bone formation inside the scaffolds. The addition of CaP likewise did not lead to increased bone formation, most likely due to low availability of CaP to the biological environment. Full article

3D bioprinting has emerged as a key tool in tissue engineering by facilitating the creation of customized scaffolds with properties tailored to specific needs. Among the design parameters, porosity stands out as a determining factor, as it directly influences critical mechanical and biological properties such as nutrient diffusion, cell adhesion and structural integrity. This review comprehensively analyses the state of the art in scaffold design, emphasizing how porosity-related parameters such as pore size, geometry, distribution and interconnectivity affect cellular behavior and mechanical performance. It also addresses advances in manufacturing methods, such as additive manufacturing and computer-aided design (CAD), which allow the development of scaffolds with hierarchical structures and controlled porosity. In addition, the use of computational modelling, in particular finite element analysis (FEA), as an essential predictive tool to optimize the design of scaffolds under physiological conditions is highlighted. This narrative review analyzed 112 core articles retrieved primarily from Scopus (2014–2025) to provide a comprehensive and up-to-date synthesis. Despite recent progress, significant challenges persist, including the lack of standardized methodologies for characterizing and comparing porosity parameters across different studies. This review identifies these gaps and suggests future research directions, such as the development of unified characterization and classification systems and the enhancement of nanoscale resolution in bioprinting technologies. By integrating structural design with biological functionality, this review underscores the transformative potential of porosity research applied to 3D bioprinting, positioning it as a key strategy to meet current clinical needs in tissue engineering. Full article

This scoping review aimed to systematically map the literature on digital workflows for the design and fabrication of customized bone grafts in oral and maxillofacial surgery. The review focused on the integration of cone-beam computed tomography (CBCT), computer-aided design (CAD), and computer-aided manufacturing (CAM) techniques for the production of personalized bone blocks. A systematic search of PubMed, Web of Science, and Ovid MEDLINE identified 151 records published between 2015 and 2025; after duplicate removal, screening, and full-text assessment, 16 articles were included. Six additional seminal studies published before 2015 were considered through manual search to provide historical background. The included studies consisted of case reports, case series, prospective clinical investigations, and preclinical experiments. Customization strategies involved synthetic hydroxyapatite scaffolds, CAD/CAM-milled allogeneic blocks, xenogeneic blocks, and digitally guided autogenous grafts. Four studies provided direct clinical documentation of customized CAD/CAM bone blocks, while the others offered complementary evidence on digital design, scaffold adaptation, or preclinical validation. Outcomes included graft adaptation, volumetric stability, implant survival, and limited histological analyses. Despite promising short-term results, no study has yet described the complete clinical workflow from CBCT acquisition to milling and implantation of a biological autologous or xenogeneic block in humans. This review underscores both the feasibility and the limitations of current approaches, highlighting the absence of fully validated digital-to-biological protocols as the main gap to be addressed in future research. Full article

Background and Objectives: Bone regeneration (BR) is a cornerstone technique in reconstructive dental surgery, traditionally using either barrier membranes, titanium meshes, or perforated non-resorbable membranes to facilitate bone regeneration. Recent advancements in 3D technology, including CAD/CAM and additive manufacturing, have enabled the development of customized scaffolds tailored to patient needs, potentially overcoming the limitations of conventional methods. Materials and Methods: A scoping review was conducted according to the PRISMA guidelines. Electronic searches were performed in MEDLINE (PubMed), the Cochrane Library, Scopus, and Web of Science up to January 2025 to identify studies on digital technologies applied to bone augmentation. Eligible studies encompassed randomized controlled trials, cohort studies, case series, and case reports, all published in English. Data regarding digital workflows, software, materials, printing techniques, and sterilization methods were extracted from 23 studies published between 2015 and 2024. Results: The review highlights a diverse range of digital workflows, beginning with CBCT-based DICOM to STL conversion using software such as Mimics and Btk-3D^®. Customized titanium meshes and other meshes like Poly Ether-Ether Ketone (PEEK) meshes were produced via techniques including direct metal laser sintering (DMLS), selective laser melting (SLM), and five-axis milling. Although titanium remained the predominant material, studies reported variations in mesh design, thickness, and sterilization protocols. The findings underscore that digital customization enhances surgical precision and efficiency in BR, with several studies demonstrating improved bone gain and reduced operative time compared to conventional approaches. Conclusions: This scoping review confirms that 3D techniques represent a promising advancement in BR. Customized digital workflows provide superior accuracy and support for BR procedures, yet variability in protocols and limited high-quality trials underscore the need for further clinical research to standardize techniques and validate long-term outcomes. Full article

Background: Vertical alveolar ridge augmentation (ARA) > 3 mm is associated with increased surgical complexity and higher complication rates. Despite the availability of various ARA techniques and graft materials, robust comparative clinical data remain limited. This retrospective multicenter study aimed to evaluate and compare surgical and patient-relevant outcomes across seven established vertical ARA techniques. Methods: This retrospective multicenter study included 70 cases of vertical ARA > 3 mm using seven different techniques (10 cases each): an iliac crest graft (ICG), intraoral autogenous bone block (IBB), allogeneic bone block (ABB), CAD/CAM ABB, CAD/CAM titanium mesh (CAD/CAM TM), magnesium scaffold (MS), and the allogeneic shell technique (ST). The outcome parameters included harvesting and insertion time, bone gain (vertical and horizontal, after a minimum of one year), graft resorption (after one year), donor site morbidity, dehiscence rate, need for material removal, and biological and general financial costs. Results: Harvesting time significantly varied among the different ARA techniques (p = 0.0025), with the longest mean durations in ICGs (51.6 ± 5.8 min) and IBBs (36.5 ± 10.8 min), and no harvesting was required for the other techniques. Insertion times also significantly differed between the different ARA techniques (p < 0.0001) and were longest in IBBs (50.1 ± 7.5 min) and the ST (47.3 ± 13.9 min). ICGs achieved the highest vertical and horizontal bone gain (5.6 ± 0.4 mm), while ABBs and CAD/CAM ABBs showed the lowest (~3.0 mm). Resorption rates significantly differed between the different ARA techniques (p < 0.0001) and were highest for ICGs (25.9 ± 3.9%) and lowest for MSs (5.1 ± 1.5%). Donor site morbidity was 100% in ICGs and 50% in IBBs, with no morbidity in the other groups. Dehiscence rates were 10% in most techniques but 30% in CAD/CAM TMs. Removals were required in all techniques except MSs. Biological and financial costs were high for ICGs and CAD/CAM ABBs and low for MSs. Conclusions: Vertical ARA techniques significantly differ regarding harvesting and insertion time, bone gain, graft resorption, donor site morbidity, dehiscence rates, removals, and costs. While ICGs achieved the highest bone volume, less invasive techniques, such as CAD/CAM-based or resorbable scaffolds, reduced biological costs and complication risks. Technique selection should be individualized based on defects, patients, and reconstructive goals. Full article

Drug-coated balloons (DCBs) have emerged as a compelling alternative to drug-eluting stents in the treatment of coronary artery disease (CAD), offering the advantage of local drug delivery without permanent vascular scaffold implantation. Initially developed for managing in-stent restenosis, DCBs seem appealing for broader indications, particularly in small vessel disease and bifurcation lesions. While paclitaxel-based DCBs remain the most investigated, newer limus formulations are showing promise and appear to be a valid alternative in early trials. Evidence from recent randomized clinical trials (RCTs) and meta-analyses highlights DCBs as a safe and effective option in selected patients, with potential benefits including lower restenosis rates, reduced need for dual antiplatelet therapy, and avoidance of late stent-related complications. As new large-scale trials near completion, DCBs are poised to take on a broader role in the treatment of CAD, particularly in patients where “leaving nothing behind” offers a clinical advantage. This review offers an overview of the DCB platforms commercially available, showing pharmacological differences, providing current indications in practical guidelines, and analyzing the most recent and impactful RCTs and meta-analyses in the field. Full article

The permeability of a porous material is the measure of the ability of fluids to pass through it. The ability to control permeability is valued by tissue engineers who manufacture tissue engineering scaffolds that house cells/tissue and facilitate tissue growth. Therefore, a scaffold design software in which permeability can be entered as a variable in determining the structure and strut topology would be a desirable tool for tissue engineering researchers. The ability to factor permeability directly into the design of scaffolds facilitates more effective bone tissue engineering by enabling optimal nutrient transport and waste removal at regeneration sites. Additionally, having the ability to control the mechanical environment by indicating a region of acceptable porosities for in vitro cell culturing is desirable. This desirability is a result of porosity being a major determining factor in permeability, where increasing porosity will generally mean a higher permeability. Thus, having an upper bound on porosity means that higher-permeability structures can be determined whilst maintaining high values of mechanical strength. In this software, a method is discussed for modifying the Kozeny–Carman equation by incorporating level-set equations for different triply periodic minimal surface (TPMS) structures. Topology analysis is computed on six different TPMS structures in the toolbox, and a relationship between a topological constant and permeability is derived through the Kozeny–Carman equation. This relationship allows for an input of permeability as a factor in the determination of pore size, porosity, and scaffold structure. This novel method allows for scaffold design based on a tailored permeability to assist successful tissue engineering. Full article

Drug-coated balloons (DCBs) have emerged as an increasingly valuable option for the treatment of coronary artery disease (CAD). Percutaneous coronary intervention (PCI) with DCBs enables the localized delivery of antiproliferative drugs directly to the target coronary lesion, avoiding the need for permanent scaffold implantation. Historically, paclitaxel-coated balloons (PCBs) have been the most used device in this context. Paclitaxel interferes with intracellular microtubule function, leading to cell cycle arrest. However, its cytotoxicity at a higher dosage and narrow therapeutic range has raised some safety concerns. To address these issues, sirolimus-coated balloons (SCBs) have been introduced as an alternative. Sirolimus acts as a cytostatic agent with potent anti-inflammatory and antiproliferative properties and is characterized by a wider therapeutic range, potentially offering a safer profile. Several experimental and clinical studies comparing the safety and efficacy of PCBs versus SCBs have yielded mixed results. Recently, a novel DCB (SirPlux Duo), which simultaneously releases both paclitaxel and sirolimus, has been tested in a porcine coronary model with promising results. In this review, we will elucidate the mechanisms of action of paclitaxel and sirolimus, examine contemporary preclinical and clinical evidence comparing PCB and SCB angioplasty, and discuss novel devices that may enhance the safety and efficacy of PCI with DCBs. Full article

The emerging paradigm of personalised bone repair embodies a transformative triad comprising bio-inspired design, digital fabrication, and the exploration of innovative materials. The increasing average age of the population, alongside the rising incidence of fractures associated with age-related conditions such as osteoporosis, necessitates the development of customised, efficient, and minimally invasive treatment modalities as alternatives to conventional methods (e.g., autografts, allografts, Ilizarov distraction, and bone fixators) typically employed to promote bone regeneration. A promising innovative technique involves the use of cellularised scaffolds incorporating mesenchymal stem cells (MSCs). The selection of materials—ranging from metals and ceramics to synthetic or natural bio-derived polymers—combined with a design inspired by natural sources (including bone, corals, algae, shells, silk, and plants) facilitates the replication of geometries, architectures, porosities, biodegradation capabilities, and mechanical properties conducive to physiological bone regeneration. To mimic internal structures and geometries for construct customisation, scaffolds can be designed using Computer-aided Design (CAD) and fabricated via 3D-printing techniques. This approach not only enables precise control over external shapes and internal architectures but also accommodates the use of diverse materials that improve biological performance and provide economic advantages. Finally, advanced numerical models are employed to simulate, analyse, and optimise the complex processes involved in personalised bone regeneration, with computational predictions validated against experimental data and in vivo studies to ascertain the model’s ability to predict the recovery of bone shape and function. Full article

The objective of this work is to review the literature on the use of three-dimensional scaffolds obtained by printing for the regeneration of bone defects in the maxillofacial area. The research question asked was: what clinical experiences exist on the use of bone biomaterials manufactured by CAD/CAM in the maxillofacial area? Prospective and retrospective studies and randomized clinical trials in humans with reconstruction area in the maxillofacial and intraoral area were included. The articles had to obtain scaffolds for bone reconstruction that were designed by computer processing and printed in different materials. Clinical cases, case series, in vitro studies and those that were not performed in humans were excluded. Six clinical studies were selected that met the established inclusion criteria. The selected studies showed heterogeneity in their objectives, materials used and types of regenerated bone defects. A high survival rate was found for dental implants placed on 3D-printed scaffolds, with rates ranging from 94.3% to 98%. The materials used included polycaprolactone, coral-derived hydroxyapatite, biphasic calcium phosphate (BCP) and bioceramics. The use of CAD/CAM technology is seen as key for satisfying variations in the shapes and requirements of different fabrics and size variations between different individuals. Furthermore, the possibility of using the patient’s own stem cells could revolutionize the way bone defects are currently treated in oral surgery. The results indicate a high survival rate of dental implants placed on 3D-printed scaffolds, suggesting the potential of this technology for bone regeneration in the maxillofacial mass. Full article

Biomimetics is the science of imitating nature’s designs and processes to create innovative solutions for various fields, including dentistry and craniofacial reconstruction. In these areas, biomimetics involves drawing inspiration from living organisms/systems to develop new materials, techniques, and devices that closely resemble natural tissue structures and enhance functionality. This field has successfully demonstrated its potential to revolutionize craniofacial procedures, significantly improving patient outcomes. In dentistry, biomimetics offers exciting possibilities for the advancement of new dental materials, restorative techniques, and regenerative potential. By analyzing the structure/composition of natural teeth and the surrounding tissues, researchers have developed restorative materials that mimic the properties of teeth, as well as regenerative techniques that might assist in repairing enamel, dentin, pulp, cementum, periodontal ligament, and bone. In craniofacial reconstruction, biomimetics plays a vital role in developing innovative solutions for facial trauma, congenital defects, and various conditions affecting the maxillofacial region. By studying the intricate composition and mechanical properties of the skull and facial bones, clinicians and engineers have been able to replicate natural structures leveraging computer-aided design and manufacturing (CAD/CAM) and 3D printing. This has allowed for the creation of patient-specific scaffolds, implants, and prostheses that accurately fit a patient’s anatomy. This review highlights the current evidence on the application of biomimetics in the fields of dentistry and craniofacial reconstruction. Full article

Analyzing the integration of scientific knowledge to guide decision-making processes supporting design challenges in engineering education is critical. However, effectively engaging in informed design decision-making processes is challenging, particularly in the context of online education. Simulation-based learning can bring authentic design practices to online education, but effective guidance and scaffolding must be provided to learners. Therefore, this research investigates the implications of integrating simulation-based learning with an argumentation framework to guide students in incorporating scientific knowledge into their design decisions, particularly in designing energy-efficient housing. This study took place during online learning due to the COVID-19 pandemic and was implemented within a first-year engineering technology undergraduate course. It aimed to analyze students’ decision-making processes when designing a zero-energy home for a Midwestern city using Aladdin, an integrated CAD/CAE platform that can be used to design a structure and simulate its function within a single system. This study investigates how students informed their decision-making processes in design for energy-efficient homes and the recurring trends in students’ designs related to economic decision making and energy science. The overall results show how cost constraints significantly influenced students’ observation and argumentation processes during their design challenge, highlighting the pivotal role of economic considerations in shaping their decision making. Moreover, the findings underscore the importance of holistic approaches in providing insights into teaching strategies for online learning, particularly in navigating the intersection of scientific and economic factors in design challenges. Full article

Polymer-infiltrated ceramic network (PICN) materials have gained considerable attention as tooth-restorative materials due to their mechanical compatibility with human teeth, especially with computer-aided design and computer-aided manufacturing (CAD/CAM) technologies. However, the designed geometry affects the mechanical properties of PICN materials. This study aims to study the relationship between manufacturing geometry and mechanical properties. In doing so, zirconia-based PICN materials with different geometries were fabricated using a direct ink-writing process, followed by copolymer infiltration. Comprehensive analyses of the microstructure and structural properties of zirconia scaffolds, as well as PICN materials, were performed. The mechanical properties were assessed through compression testing and digital image correlation analysis. The results revealed that the compression strength of PICN pieces was significantly higher than the respective zirconia scaffolds without polymer infiltration. In addition, two geometries (C-grid 0 and C-grid 45) have the highest mechanical performance. Full article