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- Does Printing Orientation Matter in PolyJet 3D Printed Teeth for Endodontics? A Micro-CT AnalysisPublication . Barbosa, Cláudia; Reis, Tiago; Reis, José B.; Franco, Margarida; Batista, Catarina; Ruben, Rui B.; Martín-Biedma, Benjamín; Martín-Cruces, JoseThis study aimed to identify the optimal printing orientation (X, Y, or Z axis) and positioning of a mandibular molar presenting an isthmus using PolyJet™ technology. The influence of these parameters on dimensional accuracy and on the behavior of 3D-printed teeth (3DPT) during endodontic preparation with ProTaper Gold® system was evaluated. Six groups (XA, XB, YA, YB, ZA, ZB; n = 10) were printed with different axis orientations and distinct isthmus positions relative to the build platform. All samples underwent micro-computed tomography scanning before and after endodontic preparation. Regarding preoperative analyses—canal volume, centroids, and total tooth volume and area—no significant differences were found between groups XA–YA or XB–YB (p > 0.05), supporting their comparability. In contrast, groups ZA and ZB differed significantly from all others (p < 0.05), failing to meet equivalence required for further comparison, and were therefore excluded. Postoperative evaluation—volume change, centroid displacement, transportation, and unprepared areas—revealed no significant differences between XA–YA and XB–YB. Within the limitations of this study, both printing orientation and position affected the accuracy and repeatability of 3DPT, with positioning exerting the greatest influence, while their behavior towards endodontic preparation remained consistent across orientations.
- Effectiveness of Wearable Devices for Posture Correction: A Systematic Review of Evidence from Randomized and Quasi-Experimental StudiesPublication . Caixeiro, Diogo; Cordeiro, Tomás; Constantino, Leandro; Carreira, João; Mendes, Rui; Silva, Cândida G.; Castro, Maria AntónioIntroduction: The increasing development of wearable devices for postural monitoring (provide feedback on posture) or correction (mechanical or biofeedback to promote change) is partly driven by the rising prevalence of poor posture in the general population and its impact on pain perception and functional capacity. Objective: Examine the effects of wearable devices on posture correction or prevention and on related outcomes, including postural alignment, muscle activity, pain and functional performance. Methods: The review followed the PRISMA 2020 guidelines. Searches were performed in PubMed, Scopus, Web of Science, and PEDro for studies published between 2012 and 2025. Eligible studies included randomized controlled trials and quasi-experimental designs involving participants with postural deviations or at risk of developing them, who underwent interventions using wearable devices that provided vibratory, auditory, visual, or tactile biofeedback. Results: Eight studies reported immediate improvements in postural alignment, body awareness, and self-reported pain, particularly with devices providing vibratory or visual biofeedback. Functional task stability improved, and muscle activity during risky postures decreased. However, the strong heterogeneity across devices and protocols, small sample sizes, short intervention durations, and, in some cases, the lack of independent control groups limit the strength and generalizability of these findings. Conclusions: Wearable devices have potential as complementary tools in physiotherapy due to their autonomous and potentially effective nature. Nevertheless, current evidence remains insufficient to support definitive clinical recommendations.
- Green Marketing and Green Brand – The Toyota CasePublication . Simão, Lídia; Lisboa, AnaThe main aim of this study is to contextualize sustainability and call for its consideration in firms’ management, namely via green marketing and green brand. Although the concept of sustainable development appeared in the 1970s, only recently has it been incorporated by firms. Development, to be sustainable, has to satisfy the needs of current generations, without compromising the ability of future generations to satisfy theirs. This requires a balance in managing social, economic and environmental aims, both current and future. Given the increasing evidence of environmental problems, the awareness of the need for sustainability has been expanding, at the individual and at the corporate level. Environmentally responsible firms obtain multiple benefits, such as cost reduction (due to the lower resource consumption, such as water or energy), profit increase (from recycling and residuals reuse), production process enhancement (given the cleaner and more efficient technologies), corporate image upgrading, improvement of brand awareness and value as well as performance. Oppositely, firms associated to non-sustainable actions are impaired in those areas. In the scope of a green strategy, a green brand obtains attributes and benefits related to the reduction of the brand’s environmental impact. As such, it should promote the perception of an environmentally healthy brand and disclose such benefits to the more environmentally aware consumers. We present the case of Toyota, a brand with patent and acknowledged efforts in what regards sustainability. It is a worldwide reference of corporate responsibility and of a successful use of green marketing. The brand’s challenge to reach important environmental goals until 2050, demonstrates its commitment and endeavor in multiple crucial aspects of sustainability management. Therefore, Toyota is in a prominent position as a “global green brand”.
- An open-source GUI application for segment foetal ultrasound imagesPublication . Dinis, J. C.; Moraes, T. F.; Amorim, P. H. J.; Amorim, O. H. J.; Silva, J. V. L.; Ruben, Rui B.There are several commercial software for medical image dataset segmentation. However, most of them are expensive and not user-friendly. With our proposal of a new opensource software with a simple and specific graphical user interface (GUI), it is easy to segment a foetus from a 3D ultrasound medical image dataset. The segmented portion of images can be converted into a stereolithography (STL) file format for 3D print technologies in order to obtain an accurate physical reproduction of the model segmented. Despite the large number of segmentation algorithms available, this new GUI has three specific possibilities (threshold, region growing and Chan-Vese) in order to keep it simple and efficient. For the same reason, the GUI has just three noise filters available in order to reduce speckle. Besides GUI simplicity, a good segmentation quality was achieved. The main purpose of our proposal is to segment foetal 3D ultrasound images and to make this task quick, easy and efficient.
- 3D-printed multisampling holder for microcomputed tomography applied to life and materials science researchPublication . Vasconcelos, Isabel; Franco, Margarida; Pereira, Mário; Duarte, Isabel; Ginjeira, António; Alves, NunoThe aim of this work was to design, fabricate, test and validate a 3D-printed multisampling holder for multi-analysis by microcomputed tomography. Different raw materials were scanned by microcomputed tomography. The raw material chosen was used to fabricate the holder by 3D printing. To validate the multisampling holder, five teeth were filled with a high density-material and scanned in two ways: a single and a multisampling scan mode. For each tooth, the root canal filling volume, porosity volume, closed pore volume, and open pore volume were calculated and compared when the same tooth was scanned in the two sampling scan mode. ABSplus P430™ allowed a high transmission value (84.3 %), and then it was the polymeric material selected to fabricate the holder. In a single sampling scan mode, the scan duration for scanning five teeth was 87.42 min, contrasting with 21.51 min for a multisampling scan mode, which scanned five teeth at the same time. The scan duration time and the cost using a multisampling holder represented a reduction of 75 % and the data volume generated represented a reduction of 60 %. Comparing the two scan modes, the results also showed that the difference of root canal filling volume, porosity volume, closed pore volume, and open pore volume was not statistically significant (p > .05). The multisampling holder was validated to do multi-analysis by microcomputed tomography without significant loss of quantitative accuracy data, allowing a reduction in scan duration time, imaging cost, and data storage.
- Additive manufacturing of tissues and organsPublication . Melchels, Ferry P.W.; Domingos, Marco; Klein, Travis J.; Malda, Jos; Bártolo, Paulo J.; Hutmacher, Dietmar W.Additive manufacturing techniques offer the potential to fabricate organized tissue constructs to repair or replace damaged or diseased human tissues and organs. Using these techniques, spatial variations of cells along multiple axes with high geometric complexity in combination with different biomaterials can be generated. The level of control offered by these computer-controlled technologies to design and fabricate tissues will accelerate our understanding of the governing factors of tissue formation and function. Moreover, it will provide a valuable tool to study the effect of anatomy on graft performance. In this review, we discuss the rationale for engineering tissues and organs by combining computer-aided design with additive manufacturing technologies that encompass the simultaneous deposition of cells and materials. Current strategies are presented, particularly with respect to limitations due to the lack of suitable polymers, and requirements to move the current concepts to practical application.
- A Note on the “Smith is Huq” ConditionPublication . Martins-Ferreira, Nelson; Van der Linden, TimWe show that two known conditions which arose naturally in commutator theory and in the theory of internal crossed modules coincide: every starmultiplicative graph is multiplicative if and only if every two ef fective equivalence relations commute as soon as their normalisations do. This answers a question asked by George Janelidze.
- Quiescent and shear-induced non-isothermal crystallization of isotactic polypropylene-based nanocompositesPublication . Silvestre, Clara; Pezzuto, Marilena; Duraccio, Donatella; Mitchell, Geoffrey R.; Cimmino, SossioThe paper reports a study of the effect of the addition of clay nanoparticles on melt rheology, phase structure, and non-isothermal crystallization process of isotactic polypropylene/hydrogenated oligocyclopentadiene (iPP/HOCP) system in quiescent conditions by DSC and under shear applied at different temperatures by SAXS. For both crystallization conditions, the addition of clay and/or HOCP shifts always the crystallization onset to lower values with respect to iPP. These results can be attributed to the diluent effect of HOCP that causes a decrease in the rate of nucleation and grow of the crystals, to the presence of segregated non-crystallizable phases/particles which hinder the transport of macromolecules chains toward the growing nuclei, and to the formation of beta iPP crystals and in the case of shearinduced crystallization to the presence of HPS which seems to reduce, mainly at low Ts, the amount of oriented polymer crystals, which are nuclei for the crystallization. At a given composition, the crystallization temperatures related at the crystallization under shear are always higher that those obtained by quiescent crystallization supporting the idea that the presence of extended chains in these samples act as nucleating agents favoring the crystallization process of iPP.
- On the optimal shape of hip implantsPublication . Ruben, Rui; Fernandes, Paulo R.; Folgado, JoãoThe success of a total hip arthroplasty is strongly related to the initial stability of the femoral component and to the stress shielding effect. In fact, for cementless stems, initial stability is essential to promote bone ingrowth into the stem coating. An inefficient primary stability is also a cause of thigh pain. In addition, the bone adaptation after the surgery can lead to an excessive bone loss and, consequently, can compromise the success of the implant. These factors depend on prosthesis design, namely on material, interface conditions and shape. Although, surgeons use stems with very different geometries, new computational tools using structural optimization methods have been used to achieve a better design in order to improve initial stability and therefore, the implant durability. In this work, a multi-criteria shape optimization process is developed to study the relationship between implants performance and geometry. The multi-criteria objective function takes into account the initial stability of the femoral stem and the effect of stress shielding on bone adaptation after the surgery. Then, the optimized stems are tested using a concurrent model for bone remodeling and osseointegration to evaluate long-term performance. Additionally, the sensitivity to misalignments is analyzed, since femoral stems are often placed in varus or valgus position. Results show that the different criteria are contradictory resulting in different characteristics for the hip stem. However, the multi-criteria formulation leads to compromise solutions, with a combination of the geometric characteristics obtained for each criterion separately.
- A Hybrid Processing Approach to the Manufacturing of Polyamide Reinforced Parts with Carbon FibersPublication . Silva, M; Pereira, A. M.; Alves, N.; Mateus, A.; Malça, C.The use of thermoplastic composites reinforced with long or continuous fibers underwent an amazing increase due to advantages such as good mechanical performance, high temperature resistance, recyclable and chemical stability when compared with simple thermosetting matrices. These advantages allowed for the replacement of thermosetting systems by composites that led to the discovery of new applications. However, the processing procedure of thermoplastics reinforced with prepregs yarns entails some technological and scientific challenges mainly due to its high viscosity that results in difficulty and complexity in impregnating the reinforcements. Concerning engineering components market requirements, the polyamide thermoplastic matrices reinforced with carbon fibers have a huge demand due to the versatility of the applications where they can be used. This work presents, therefore, the development of a low-cost device that combines the Fused Filament Fabrication (FFF) additive manufacturing technique together with the processing and consolidation of thermoplastic prepregs yarns for manufacturing parts made of polyamide reinforced with carbon fibers without need of post-processing operations. To evaluate the mechanical properties of the polyamide reinforced with carbon fibers, samples were manufactured and three point bending and tensile tests were done. From results it was demonstrated the very high structural strength to both bending and tensile loads of tested material.