Methods for medical applications

Cerebral aneurysm is a complex vascular pathology, and the assessment of its rupture risk is often based on qualitative criteria and clinical expertise. The present study aims to develop an objective parameter to support risk evaluation by integrating morphological and hemodynamic analyses. A novel morphological parameter has been introduced, combining key geometric features extracted from 3D vessel reconstructions of middle cerebral artery bifurcations. Computational fluid dynamics (CFD) simulations were conducted to analyze hemodynamic factors such as wall shear stress and intra-aneurysmal pressure, both of which are associated with aneurysm growth and rupture risk. Particular attention was given to defining physiologically accurate boundary conditions, essential for obtaining reliable results. The new morphological parameter alignment with clinical evaluations suggesting its potential to enhance the assessment of aneurysm operability and improve surgical decision-making.

Keywords: Cerebral aneurysm , CFD , Hemodynamics , Morphology

Accurate simulation of respiratory dynamics is essential for advancing the diagnosis and treatment of pulmonary diseases. This review analyzes current methodologies for modelling lung mechanics during insufflation and exsufflation, focusing on airflow simulations in the tracheobronchial tree. 45 studies were selected through a structured screening process and evaluated based on modelling approaches, simulation techniques, boundary conditions, and clinical applicability. The review identifies three main strategies for 3D TB model generation: segmentation of DICOM images, CAD-based geometries, and hybrid methods. While DICOM segmentation ensures anatomical realism, it is limited in generational depth. Conversely, CAD and hybrid approaches extend model coverage but may compromise subject specificity. Simulation methods include Computational Fluid Dynamics, Fluid–Structure Interaction, biomechanical, structural and statistical models, MR-Linac workflows, and neural networks. Among these, CFD remains the most widely adopted due to its accessibility and maturity, whereas FSI and hybrid CFD–FSI models offer superior physiological fidelity. The review wants to highlight the importance of combining detailed anatomical modelling with dynamic simulation frameworks to improve clinical interventions, particularly in lung surgery. Future work should focus on integrating patient-specific imaging, advanced boundary conditions, and multiscale modelling to enable more precise and scalable respiratory simulations.

Keywords: Computational fluid dynamics (CFD) , Fluid–Structure Interaction (FSI) , Lung insufflation–exsufflation , Patient-specific modeling , Tracheobronchial tree

Traditional surgical training methods often lack the immersive and interactive elements necessary for optimal skill acquisition. Virtual reality (VR) technology has emerged as a transformative tool in surgical education, offering realistic simulations that enhance technical proficiency, psychomotor skills, and cognitive planning. This paper presents a novel collaborative cross-platform VR framework that supports multi-user interaction, enabling trainees and instructors to engage in a shared virtual environment. Structured around a modular digital hospital, the system facilitates real-time training sessions, interactive knowledge sharing, and procedural simulations with integrated feedback mechanisms. A user study demonstrated a significant reduction in errors, improved precision, and faster task completion, underscoring the system's effectiveness in enhancing surgical training efficiency. Participants rated usability highly, highlighting the system's intuitive design, engagement, and potential for democratizing surgical education.

Keywords: Collaborative Learning , Digital Hospital , Medical Simulation , Multi-User VR , Surgical Training , Virtual Reality

Congenital heart diseases (CHD) are structural birth abnormalities of the heart, requiring complex surgical treatment due to anatomical variability and the small size of the affected structures. Hands-on surgical training is essential, and recent advancements in 3D printing have enabled the creation of detailed heart models. However, 3D printed models often lack the mechanical properties of real human tissue. Silicone offers a promising alternative, due to its varied hardness levels and cost-effectiveness. This study aims to propose and test a novel simulator for CHD repair procedures, with a silicone heart model. A pediatric heart with a ventricular septal defect (VSD) was considered and a simulation environment was designed based on the dimensions and proportions of an infant's chest, incorporating a modular platform with a rib cage. A silicone heart was successfully manufactured via a single-piece injection molding procedure. The process used a soluble internal material and a multi-part external shell. The full simulator setup was evaluated by 6 surgeons to address anatomical accuracy and suitability in surgical training of CHD. Despite some limitations and drawbacks were highlighted, the presented solution was found to be an overall useful tool for enhancing surgical training in CHD repair.

Keywords: 3D printing , Congenital Heart Diseases (CHD) , Silicone molding , Simulation-based training , Ventricular Septal Defect (VSD)

In this article, the authors cited references 19–36 in contexts where they became redundant. While the authors acknowledge the value of these references, due to inappropriate locations they have repositioned the citations throughout the article to enhance clarity and coherence. Additionally, the authors have included a typographical error in Table 2 with the ‘Poisson ν' and ‘Young's Modulus E [MPa]' values for ‘Cancellous' showing as switched. The authors have confirmed that the values ‘100' and 0.2′ are to be switched. In the original article, the following statements were used to cite references 19–36 in Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods': “… The bone material of the vertebrae consists of two parts, cortical and cancellous. The mechanical properties have been modelled as a homogeneous and isotropic material [19,20,21,22,23,24,25,26,27,28]. There are different approaches in literature for modelling the cortical and cancellous structure, some authors use orthotropic models, however, in the scientific literature the simplification to isotropic material is widely used [29,30,31,32,33,34,35,26,36] …” The statements in Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods' is updated to include only references [20], [26], [29] and [30]. The updated statement should be as below: “… The bone material of the vertebrae consists of two parts, cortical and cancellous. The mechanical properties have been modelled as a homogeneous and isotropic material [20, 26]. There are different approaches in literature for modelling the cortical and cancellous structure, some authors use orthotropic models, however, in the scientific literature the simplification to isotropic material is widely used [29,30] …” The citation [19] has been moved to ‘Section 1. Introduction'. The original statement can be found below: “Unfortunately, a range of disorders and diseases can compromise the integrity and functioning of the spine, leading to pain, disability, and a reduced quality of life …” The correct version of the statement with citation [19] added should be as below: “Unfortunately, a range of disorders and diseases can compromise the integrity and functioning of the spine, leading to pain, disability, and a reduced quality of life [19] …” The citation [21] has been moved to Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods'. The original statement can be found below: “… Four loading conditions were simulated, which involved a compressive force of a maximum value of 1000 N, to which was added, individually, a rotational load …” The correct version of the statement with citation [21] added should be as below: “… Four loading conditions were simulated, which involved a compressive force of a maximum value of 1000 N, to which was added, individually, a rotational load [21] …” The citation [22] has been moved to Section ‘1. Introduction'. The original statement can be found below: “… Age plays a pivotal role in the distribution of lesions …” The correct version of the statement with citation [22] added should be as below: Age plays a pivotal role in the distribution of lesions [22] …” The citation [23] has been moved to Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods'. The original statement can be found below: “… The Poisson coefficient (Eq. (2.1)) will depend on two other coefficients, namely structural damping (Eq. (2.2)) and volumetric deformation (Eq. (2.3)) [40] …” The correct version of the statement with citation [23] added should be as below: “… The Poisson coefficient [23] (Eq. (2.1)) will depend on two other coefficients, namely structural damping (Eq. (2.2)) and volumetric deformation (Eq. (2.3)) [40] …” The citations [24] and [25] have been moved to Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods'. The original statement can be found below: “… The authors were able to apply compressive loads up to over 1000 N without any sign of instability …” The correct version of the statement with citations [24] and [25] added should be as below: “… The authors were able to apply compressive loads up to over 1000 N without any sign of instability [24,25] …” The citation [27] has been moved to Section ‘1. Introduction'. The original statement can be found below: “… Over the years, research and clinical practice have led to the development of various treatment techniques aimed at restoring stability and proper functioning of the spine …” The correct version of the statement with citation [27] added should be as below: “… Over the years, research and clinical practice have led to the development of various treatment techniques aimed at restoring stability and proper functioning of the spine [27] …” The citation [28] has been moved to Section ‘2.1 Anatomy of the lower part of the spine and diseases'. The original statement can be found below: “… When the intervertebral disc deteriorates or ruptures, it can cause pain and dysfunction in the spine …” The correct version of the statement with citation [28] added should be as below: “… When the intervertebral disc deteriorates or ruptures, it can cause pain and dysfunction in the spine [28] …” The citation [31] has been moved to Section ‘4.3 Range of motion'. The original statement can be found below: “… Therefore, the simulation can be improved, e.g. by including the muscular apparatus …” The correct version of the statement with citation [31] added should be as below: “… Therefore, the simulation can be improved, e.g. by including the muscular apparatus [31] …” The citation [32] has been moved to Section ‘1. Introduction'. The original statement can be found below: “‥Among the various treatment approaches for spine stabilization, the Lateral Mass Screw (LMS) is an established method used for treating a wide range of spinal conditions …” The correct version of the statement with citation [32] added should be as below: “‥Among the various treatment approaches for spine stabilization, the Lateral Mass Screw (LMS) is an established method used for treating a wide range of spinal conditions [32] …” The citation [33] has been moved to Section ‘2.1 Anatomy of the lower part of the spine and diseases'. The original statement can be found below: “… Diseases that can affect the intervertebral disc include disc herniation, disc degeneration and spinal stenosis …” The correct version of the statement with citation [33] added should be as below: “… Diseases that can affect the intervertebral disc include disc herniation, disc degeneration and spinal stenosis [33] …” The citation [34] has been moved to Section ‘1. Introduction'. The original statement can be found below: “ …. These areas show the highest rates of degeneration, affirming the notion that these zones are particularly exposed to mechanical stresses and thus at greater risk …” The correct version of the statement with citation [34] added should be as below: “ …. These areas show the highest rates of degeneration, affirming the notion that these zones are particularly exposed to mechanical stresses and thus at greater risk [34] …” The citation [35] has been moved to Section ‘3.3 Range of motion'. The original statement can be found below: “… The Range of Motion (ROM) is a crucial aspect of spinal biomechanics, representing the relative range of motion between various pairs of vertebrae, in our case study these are L4-L5 and L5-S1 (Table 13) …” The correct version of the statement with citation [35] added should be as below: “… The Range of Motion (ROM) is a crucial aspect of spinal biomechanics, representing the relative range of motion between various pairs of vertebrae [35], in our case study these are L4-L5 and L5-S1 (Table 13) …” The citation [36] has been moved to Section ‘2.3 Simulation – mechanical properties, constraint system, contacts and methods'. The original statement can be found below: “… The elements were arranged in the anatomical direction given in the literature [41] (Table 4) …” The correct version of the statement with citation [36] added should be as below: “… The elements were arranged in the anatomical direction given in the literature [36, 41] (Table 4) …” The original version of Table 2 can be found below: [Table presented] The table has been updated so that the value of ‘100' for ‘Poisson v' of ‘Cancellous' is switched with value ‘0.2' for ‘Young's Modulus E [MPa]' values of ‘Cancellous' The correct version of the table should be as below: [Table presented] The references associated with the changes can be found below: [19] S.J. Atlas, R.A. Deyo, Evaluating and managing acute low back pain in the primary care setting, J. Gen. Intern. Med. 16 (2001) 120–131. [20] C.-S. Chen, C.-K. Cheng, C.-L. Liu, W.-H. Lo, Stress analysis of the disc adjacent to interbody fusion in lumbar spine, Med. Eng. Phys. 23 (2001) 485–493. [21] F. Heuer, H. Schmidt, L. Claes, H.-J. Wilke, A new laser scanning technique for imaging intervertebral disc displacement and its application to modelling nucleotomy, Clin. Biomech. 23 (2008) 260–269. [22] F. Heuer, H. Schmidt, Z. Klezl, L. Claes, H.-J. Wilke, Stepwise reduction of functional spinal structures increase range of motion and change lordosis angle, J. Biomech. 40 (2007) 271–280. [23] H.-M. Lin, Y.-N. Pan, C.-L. Liu, L.-Y. Huang, C.-H. Huang, C.-S. Chen, Biomechanical comparison of the K-ROD and Dynesys dynamic spinal fixator systems – a finite element analysis, Bio Med. Mater. Eng. 23 (2013) 495–505. [24] D.W. McMillan, D.S. McNally, G. Garbutt, M.A. Adams, Stress distributions inside intervertebral discs: the validity of experimental ‘stress profilometry, Proc. Inst. Mech. Eng. Part H J. Eng. Med. 210 (1996) 81–87. [25] A. Rohlmann, S. Neller, L. Claes, G. Bergmann, H.-J. Wilke, Influence of a follower load on intradiscal pressure and intersegmental rotation of the lumbar spine, Spine 26 (2001) E557–E561. [26] H. Schmidt, M. Bashkuev, M. Dreischarf, A. Rohlmann, G. Duda, H.-J. Wilke, A. Shirazi-Adl, Computational biomechanics of a lumbar motion segment in pure and combined shear loads, J. Biomech. 46 (2013) 2513–2521. [27] A.Y.L. Wong, G. Harada, R. Lee, S.D. Gandhi, A. Dziedzic, A. Espinoza-Orias, M. Parnianpour, P.K. Louie, B. Basques, H.S. An, D. Samartzis, Preoperative paraspinal neck muscle characteristics predict early onset adjacent segment degeneration in anterior cervical fusion patients: a machine-learning modelling analysis, J. Orthop. Res. 39 (2021) 1732–1744. [28] I. Yamamoto, M.M. Panjabi, T. Crisco, T. Oxland, Three-dimensional movements of the whole lumbar spine and lumbosacral joint, Spine 14 (1989) 1256–1260.] [29] A. Faizan, A. Kiapour, A.M. Kiapour, V.K. Goel, Biomechanical analysis of various footprints of transforaminal lumbar interbody fusion devices, J. Spinal Disord. Tech. 27 (2014) E118–E127. [30] V.K. Goel, A. Mehta, J. Jangra, A. Faizan, A. Kiapour, R.W. Hoy, A.R. Fauth, Anatomic facet replacement system (afrs) restoration of lumbar segment mechanics to intact: a finite element study and in vitro cadaver investigation, Int. J. Spine Surg. 1 (2007) 46–54. [31] Y. Guan, N. Yoganandan, J. Moore, F.A. Pintar, J. Zhang, D.J. Maiman, P. Laud, Moment–rotation responses of the human lumbosacral spinal column, J. Biomech. 40 (2007) 1975–1980. [32] A. Kiapour, D.G. Anderson, D.B. Spenciner, L. Ferrara, V.K. Goel, Kinematic effects of a pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis, J. Neurosurg. Spine 17 (2012) 314–320. [33] A. Nachemson, Lumbar intradiscal pressure: experimental studies on post-mortem material, Acta Orthop. Scand. 31 (1960) 1–104. [34] M.M. Panjabi, T.R. Oxland, I. Yamamoto, J.J. Crisco, Mechanical behavior of the human lumbar and lumbosacral spine as shown by three-dimensional loaddisplacement curves, J. Bone Jt. Surg. 76 (1994) 413–424. [35] M.J. Pearcy, Stereo radiography of lumbar spine motion, Acta Orthop. Scand. 56 (1985) 1–45. [36] Z.-C. Zhong, S.-H. Wei, J.-P. Wang, C.-K. Feng, C.-S. Chen, C. Yu, Finite element analysis of the lumbar spine with a new cage using a topology optimization method, Med. Eng. Phys. 28 (2006) 90–98.

This paper investigates the mechanical behaviour of biomimetic structures produced using L-PBF technology. Specifically, the triply periodic minimal surface (TPMS) gyroid structure was analysed. The TPMS are receiving significant attention in biomedical applications to produce structures with high strength-to-weight ratio, better control over the transition in properties between the prosthesis and the bone tissue, such as stiffness and density, and improved interface adhesion. The mechanical characterisation of these structures is the current challenge for researchers. We propose a preliminary modelling strategy for a homogenisation procedure based on the Representative Volume Element (RVE) theory and traditional mesoscale and macroscale finite element (FE) analysis integrated with evaluating the anisotropy induced by the printing process. The results indicate that the L-PBF produces an orthotropic base material, the unit cell exhibits an anisotropic behaviour, and the macroscopic modelling reduces the computational cost. However, a mesoscopic approach is necessary to define the anisotropic elastic matrix of the cell. © 2025, Association of American Publishers.

Keywords: Anisotropy , Biomimetic , L-PBF , Meso and Macroscale , TPMS

This paper describes how to create interactions between the virtual world and the medical environment to solve one of the problems frequently encountered during the design phases of operations, highlighting the importance of this project in the realm of Applied R&D + i for high-detail, patient-specific medical operations. In particular, rotations and translations required to solve valgus and varus problems of the tibia and femur are analyzed. Currently, prostheses are produced using non-specific software that requires the presence of an external operator. A virtual reality (VR) application to improve the interaction between the software and the surgeon, thus simplifying the prosthesis design process, is presented. The method proposed in this paper applies mechanical design to the medical field, starting from the principles of Industry 4.0 for human–machine interaction. Virtual Reality implements mechanical concepts such as the hinge and its function in virtual environments like Unity. This approach allowed us to limit the movement of an object in space to rotations around an axis defined by the end user, making these rotations ‘parametric', i.e. traceable to finite mathematical values. It was demonstrated that the design of wedge-shaped prostheses for realigning the tibia and femur during surgery has been thus simplified.

Keywords: Augmented reality , Parametric operation , Surgery planification , Training , Virtual reality

Assessing the pliability of burn scars represents a key clinical challenge for monitoring the healing process and optimising rehabilitation treatments. Currently, most of the methods used to assess scar quality are based on subjective evaluations, limiting the accuracy and reproducibility of the results. This study presents the development of an innovative scanner based on the Digital Image Correlation (DIC) technique to objectively measure changes in scarred skin deformation. The designed system integrates a hardware configuration with an image processing algorithm able to detect with high accuracy the deformations of the skin subjected to a known stress, allowing the calculation of the pliability value. By comparing two values obtained in two successive sessions, it is possible to verify the improvement in the health of the scar. Preliminary tests have shown that the system is able to provide reliable and reproducible data, confirming the technology's potential for scar quality assessment. The implementation of this technology could help change the management of burn scars, improving patients' quality of life through more accurate diagnoses and more effective treatments.

Keywords: 3D printing , Burn scars , CAD modelling , Digital image correlation , Pliability

Background: Nonconventional fabrication technologies (e.g., additive manufacturing and 3D bioprinting) represent a challenging approach to the design of 3D scaffolds as extracellular matrix analogues with appropriate properties for supporting cell behavior over time. Methods: A strategy to develop 3D additive manufactured hybrid scaffolds with dual porosity and tailored morphological and mechanical/functional features was proposed via the combination of synthetic (poly-ε-caprolactone) and natural (chitosan) polymers. Design of 3D additive manufactured hybrid scaffolds, morphological analysis, in vitro swelling and degradation measurements, mechanical measurements, antimicrobial assays against both oral cavity-specific and nonoral bacteria, and biological assays using periodontal ligament stem cells (PDLSCs) or human osteosarcoma cells (MG63) were carried out. Results: The inclusion of the chitosan network improves the dimensional stability of the structure as well as the cell retention effect, ensuring antimicrobial activity.

Keywords: antimicrobial activity , dental, oral, and craniofacial tissue repair , design for additive manufacturing , hybrid structure , mechanical measurements , morphological analyses

Tuning materials' micro/nanoporous architecture is pivotal in maintaining microenvironmental homeostasis. Bioinspired micro/nanoporous scaffolds, based on triply periodic minimal surface (TPMS), present promising avenues for restoring microenvironmental equilibrium in tissue regeneration. Moreover, micro/nanoporous TPMS holds potential for applications in wastewater treatment and pollutant removal to restore microenvironmental homeostasis. 3D printing provides high flexibility in fabricating these multifunctional scaffolds with precise pore geometry and permeability control. However, printing micro/nanoscale pores using material extrusion (MEX) is still challenging. To address this issue, this study presents a novel approach to print soft micro/nanoporous scaffolds. A polymer blend of thermoplastic polyurethane elastomer (TPE) and polyvinyl alcohol (PVA) filament is selected to print gyroid-based scaffolds. Then, the water-soluble PVA molecules are removed, allowing for the creation of scaffolds with controllable porosity at the nanometer scales. The link between non-porosity, nanoporosity, mechanical behavior, and structure topology is investigated, and its impact on cell viability evaluated. Findings demonstrate that these 3D-printed scaffolds with multiscale porosity exhibit exceptional pollutant adsorption capabilities and enhance oil/water separation efficiency.

Keywords: Lattice structures , Material extrusion , Nanoporous structures , Superoleophilic , Superwetting , Triply periodic minimal surfaces

The healthcare sector is undergoing a transformative revolution through the widespread adoption of 3D-printing technologies, as evidenced by a wealth of applications already available in the literature. These innovations have opened up new design possibilities and paved the way for personalized solutions that enhance the care of patients and healthcare professionals. This chapter explores the current and potential contributions of 3D printing to healthcare, examining diverse solutions and strategies facilitated by the continuous technological advancements in additive manufacturing. A hypothetical patient's journey is envisioned to contextualize the benefits patients and healthcare practitioners can derive from 3D-printed interventions. Additionally, this chapter contemplates unresolved challenges in integrating 3D printing into healthcare, such as the need for robust design and manufacturing procedures, essential competencies and roles, and the economic feasibility of these solutions. These questions serve as catalysts for further investigation and discussion. © 2025 Elsevier Inc.

Keywords: 3D printing , biomedical engineering , care , design for additive manufacturing , drug development , in situ printing , patient journey , personalized medicine , regenerative medicine , robotic-assisted 3D printing

Binder Jetting (BJT) is a promising, yet scarcely explored, additive manufacturing technology suitable for the production of orthopedic surgical instruments, offering design flexibility, material versatility, and cost-effectiveness compared to traditional subtractive manufacturing. This study assesses the feasibility of metal BJT for manufacturing surgical instruments used in knee and hip arthroplasty. Given the limited availability of literature data about such a technology, a preliminary evaluation of sample density, mechanical properties, and dimensional accuracy was performed, taking into account the main geometrical features characterizing surgical instruments. The results demonstrate that BJT enables the fabrication of lightweight and complex geometries while achieving satisfying mechanical properties. Thin walls (0.2 mm), small holes (0.5 mm), and cylindrical extrusions (0.7 mm) were successfully printed, providing insights into BJT resolution limits. However, shrinkage during sintering was a significant challenge, requiring tailored sintering supports and counter-deformation strategies for dimensional and geometrical accuracy. The application of linear scaling factors partially mitigated anisotropic shrinkage, with deviations up to 0.44 mm for prismatic samples. Mechanical properties varied with the z-level in the print chamber, limiting the repeatability of components' performance within the printing volume. In addition, lightweight designs for surgical instruments, such as trial acetabular cups and femoral stems, were successfully manufactured, achieving significant weight reduction while maintaining functional performance. The study identifies critical Design for Additive Manufacturing (DfAM) guidelines for metal BJT, emphasizing strategies to address sintering distortions. Despite challenges, BJT shows strong potential for producing customizable and lightweight surgical instruments, paving the way for its broader adoption in biomedical manufacturing.

Keywords: Design for Additive Manufacturing , Medical devices , Metal Binder Jetting , Printing resolution , Surgical instruments

The healthcare sector is a significant contributor to global greenhouse gas emissions, largely due to resource-intensive care processes. Telemedicine represents an innovative solution for managing chronic patients, with the potential to reduce environmental impacts and improve healthcare accessibility. However, current literature lacks a standardized approach to comprehensively assess the environmental and social effects of such practices. The study aims to overcome current limitations evaluating the environmental and social impacts of televisits as an alternative to traditional in-person follow-up visits for chronic heart failure (HF) patients in a large Italian hospital. The Life Cycle Assessment (LCA) steps ensure an objective and standardized environmental evaluation. Data on social and human-related aspects for preliminary mapping of social impacts has been acquired by means structured interviews. Environmental LCA using the ReCiPe 2016 method quantifies the environmental impacts of one in-person or remote visit process for a one patient, including direct and indirect emissions from transportation, energy use, paper materials and telecommunications. Internal hospital stakeholders were involved in defining aspects of interest for initial mapping of social impacts. Results demonstrate that televisits significantly reduce environmental impacts, particularly in relation to patient transportation. On the social side, stakeholders reported benefits in terms of patient's experience, care continuity, and improvement of clinical workflows. The study emphasizes the necessity of establishing continuous impact monitoring systems to ensure long-term sustainability and efficiency.

Keywords: Life cycle assessment , Socioenvironmental impacts , Sustainable development , Telemedicine , Televisit environmental impact

Background/Objectives: One of the most serious complications following implant placement in the atrophic posterior mandible is injury to the inferior alveolar nerve (IAN), which can also happen during occlusal loading of the implants. This study investigates the effects of 4 mm implant stress transmission to the inferior alveolar nerve during occlusal loading in cases of severe posterior mandibular atrophy. Methods: The computer-aided design (CAD) model was created and modified through Direct Modeling techniques. The structure of cortical and trabecular bones was simplified, and it was modeled as a cylinder block. Finite element analysis (FEA) was carried out in 3D to investigate the pressure distribution over the IAN at different implant-to-nerve distances (1.5 mm, 0.5 mm, and 0.1 mm), and stress and strain deformations were simulated in the mandibular model. Results: The results of the pressure analysis on the inferior alveolar nerve indicate that the pressure distribution at different implant-to-nerve distances (1.5 mm, 0.5 mm, and 0.1 mm) is consistently below 0.026 MPa, which corresponds to the maximum pressure range that may block nerve impulses. This occurs even at the theoretical and simulated distance of 0.1 mm, suggesting that cortical bone stiffness plays a crucial role in mitigating stress at reduced implant-to-nerve proximities. Conclusions: Within the limits of this study, ultra-short implants can be placed even less than 0.5 mm (up to 0.1 mm under the 3D-FEA hypothesis) above the inferior alveolar nerve under the 3D-FEA hypothesis, while maintaining pressure below the threshold value. This is due to the rigidity of the cortical bone, which helps to reduce pressure transmission to the nerve.

Keywords: CAD direct modeling , dental implant , finite element analysis , inferior alveolar nerve , nerve injury , short implant

The design of an assistive device for a student with disabilities to enable his inclusion into the University is based on ethical reasons. The device must be personalized starting from a participative and human centered approach. This work presents the design and development phases of a highly functional assistive device which enables a quadriplegic user, who is unable to speak, to autonomously communicate. The starting phase deals with the identification of the user needs, considering the residual mobility of a single arm and the needs of the caregivers. The motion study allows to define the requirements which enable the definition of the system architecture. A modular architecture is chosen, allowing damaged or obsolete parts to be easily replaced extending the useful life of the device, but reducing the resources consumption during the life cycle. Sustainable and recyclable materials are selected using Additive Manufacturing technologies.

Keywords: Human centered design , Inclusive design , Personalized assistive device

PURPOSE. This study aims to compare the occlusal trueness and precision of teeth manufactured using two modern digital milling processes. MATERIALS AND METHODS. A total of 38 complete dentures (CDs) were fabricated and analyzed. CDs in Group 1 (monolithic) (n = 19) were produced using a monolithic bicolor resin disk, whereas in Group 2 (oversize) (n = 19) were fabricated using the oversize process, which involves two separate resin disks of different colors. Two investigation methods were developed to evaluate trueness and precision: cusp area analysis and cusp vertex analysis. The study included three levels of analysis: a comparison of the two measurement methods, an evaluation of the monolithic versus oversize processes, and an assessment of under-and overcontouring inaccuracies. RESULTS. Statistical analysis using the Welch two-sample t-test, the non-parametric Wilcoxon signed-rank test, and the modified signed-likelihood ratio test (SLRT) revealed a statistically significant difference (P < 2.2 × 10-16) between the two measurement methods (vertex vs. area) for both the monolithic and oversize groups, with the vertex method demonstrating greater accuracy.The analysis of over-and undercontouring inaccuracies revealed that 55% of the surface for the monolithic process exhibited overcontouring, compared to 99% for the oversize process, indicating a strong tendency toward surface roughness in the latter. CONCLUSION. The monolithic milling method exhibited significantly superior accuracy compared to the oversize process (P < 05). Additionally, the Reference Point System (RPS) metrological method proved more reliable thanthe best-fit method for comparing complex structures, offering more accurate estimates of both trueness and precision. © 2025 The Korean Academy of Prosthodontics This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.

Keywords: Accuracy , Complete denture , Computer aided manufacturing , Metrology , Milling machine

Background and objective: Despite the availability of several commercial solutions for predicting the soft tissue outcomes of maxillofacial surgeries, none have proven sufficiently reliable for routine clinical use. This study proposes a 3D methodology for predicting soft tissue displacement following maxillofacial surgery without relying on mechanical modeling, unlike most existing approaches. Methods: Pre- and post-operative Cone Beam Computed Tomography scans of patients with class III malocclusion were collected. Tailored image processing and volume reconstruction techniques were applied to semi-automatically generate 3D soft tissue models. Cephalometric landmarks were identified to perform a geometrical similarity analysis among patients with the same malocclusion class undergoing the same surgical procedure. Vectorial displacement maps were generated to capture the soft tissue changes from pre- to post-operative and were then applied to the pre-operative of test patients to predict soft tissue outcomes. Euclidean distances were calculated between predicted and real post-operative positions, and the Wilcoxon signed-rank test was conducted to assess statistical differences between predicted and real landmark coordinates. Results: Error maps indicated that approximately 70 % of predicted facial points had errors below 2.5 mm, while around 10 % ranged between 2.5 mm and 3 mm. Statistically significant differences (p < 0.05) were observed only for the gonion and cheilion. Conclusion:. The findings support the validity of the geometrical similarity analysis and the vectorial displacement map approach. The simplicity and promising accuracy of the proposed method encourage further investigations across different surgical procedures. Additionally, integrating this methodology into surgical planning could offer a viable alternative to commercial solutions.

Keywords: 3D soft tissue prediction , Dental malocclusion , Displacement vectorial map , Orthognathic surgery , Soft tissue displacement

Purpose: This study aims to evaluate postoperative periprosthetic bone mineral density (BMD) at various time points following joint replacement with different implant designs and fixation techniques. Methods: Database search was conducted on MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, and CINAHL for studies analyzing bone remodelling after joint replacement (March 2002–January 2024). Inclusion criteria: English-language articles; total joint replacement; at least two BMD evaluations; observational studies, cross-sectional, prospective, retrospective, randomised controlled trials, and clinical trials. Exclusion criteria: no BMD measurement within one month after surgery; BMD data only expressed as percentage changes or graphs without numerical values; no Gruen zone evaluation for hip replacement; no periprosthetic bone evaluation for knee replacement; pharmacological treatment or comorbidities affecting BMD; revision joint replacements; irrelevant articles; no full text or no original data. Results: Sixty-eight articles matched the selection criteria. Fifty-five focused on the hip joint, 12 on the knee, and one on the shoulder. After total hip arthroplasty, the greatest bone resorption occurred in the proximal femur, peaking at 6 months. Cemented implants and tapered stems showed greater bone resorption than cementless implants and anatomical stems. BMD around the acetabular component decreased during the first 6 months but increased in regions subjected to higher loads. In total knee arthroplasty, bone loss occurred in the anterior distal femur and medial tibial plateau, with cemented and posterior-stabilised implants showing greater bone loss than cementless and cruciate-retaining designs. Conclusions: The periprosthetic BMD decreases progressively after joint replacement. The fixation technique and implant design influence the extent and pattern of this decline. These factors must be considered during the surgical planning, as they can have long-term implications for bone health and implant longevity. Further research is needed to optimise implant design and surgical techniques to mitigate BMD loss and improve patient outcomes. Level of Evidence: Level IV. © 2025 The Author(s).

Keywords: bone mineral density , fixation technique , implant design , regions of interest , total hip replacement , total knee replacement

This study presents a methodology for optimizing the design of the fossa component in temporomandibular joint (TMJ) prostheses, particularly in cases requiring replacement due to severe pathology or trauma. Leveraging advancements in 3D printing, the research aims to align prosthetic function with natural jaw movements. A multibody simulation model was used to evaluate different designs based on key performance indicators: range of motion, condylar trajectory accuracy, and contact force magnitudes. Three designs were analyzed: a compact design fossa (CDF) with a spherical condyle, an enhanced design fossa (EDF) with a more anatomically realistic structure, and a simulation-driven design (MEDF) derived from condylar motion patterns. The results indicate that CDF could lead to dislocation at 13° of mouth opening. In contrast, EDF and MEDF safely enabled full opening (20°), closely replicated natural condyle trajectories (with deviations under 2.5 mm in all directions), and reduced contact forces, which can contribute to a longer prosthesis lifespan. MEDF showed the lowest peak contact force (−21% compared to EDF). The study successfully established a framework for evaluating and guiding patient-specific TMJ prosthetic designs, enhancing both functional rehabilitation and mechanical durability by minimizing wear through optimized contact dynamics.

Keywords: CAD , mandible kinematics , motion tracking , multibody model , patient-specific design , range of motion , TMJ prosthesis

In this article, we address the development of a robotic rehabilitation system for the upper limbs based on collaborative end-effector solutions. The use of commercial collaborative robots offers significant advantages for this task, as they are optimized from an engineering perspective and ensure safe physical interaction with humans. However, they also come with noticeable drawbacks, such as the limited range of sizes available on the market and the standard control modes, which are primarily oriented toward industrial or service applications. To address these limitations, we propose an optimization-based design method to fully exploit the capability of the cobot in performing rehabilitation tasks. In addition, we introduce a novel control architecture based on an admittance-type virtual fixture method, which constrains the motion of the robot along a prescribed path. This approach allows for an intuitive definition of the task to be performed via programming by demonstration and enables the system to operate both passively and actively. In passive mode, the system supports the patient during task execution with additional force, while in active mode, it opposes the motion with a braking force. Experimental results demonstrate the effectiveness of the proposed method.

Keywords: Assist-as-needed control , collaborative robotics , human-robot interaction , learning by demonstration (LbD) , upper limb rehabilitation , virtual fixtures