Search Results (125)

Background. Extensive partial edentulism alters the biological and functional balance of the stomatognathic system, requiring targeted pre-prosthetic procedures to optimize treatment outcomes. Objectives. The aim of this study was to assess the extent of improvement in the clinical–biological scores of the prosthetic field in patients with extensive edentulism, following pre-prosthetic interventions. Materials and Method. This prospective, cross-sectional study investigated 194 subjects with extensive partial edentulism. Clinical–biological scores, initially and following the pre-prosthetic phase, were recorded using a scoring system that evaluated dental and periodontal status, bone and mucosal support, occlusion, and mandibulo-cranial relationships. Statistical comparisons of clinical–biological scores were related to the type of prosthetic therapy. Statistical significance was considered at a p-value < 0.05. Results. There was an overall significant improvement in the clinical–biological scores initially (mean value 20.2) and after pre-prosthetic procedures (mean value 23.22) (p < 0.001). When treatment groups were divided, the implant-assisted prosthesis group showed the best improvement in all domains, followed by the conventional fixed-prostheses group (p < 0.01). Dental support improved significantly in those with semi-rigid composite prostheses (p = 0.014), while periodontal support was improved in both fixed- and hybrid-implant groups. Mucosal and bone support improved mostly in the fixed-implant groups (p = 0.014). Conclusions. Pre-prosthetic procedures significantly enhance the biological and functional readiness of the prosthetic field, with the degree of improvement influenced by the complexity and type of planned prosthetic rehabilitation. The findings underscore the value of individualized pre-prosthetic protocols as an essential component of prosthetic treatment planning. Full article

This study investigates the development of silver (Ag)-doped zirconia (ZrO₂) coatings deposited on 316LVM stainless steel via the unbalanced magnetron sputtering technique. The oxygen content in the Ar/O₂ gas mixture was systematically varied (12.5%, 25%, 37.5%, and 50%) to assess its influence on the resulting coating properties. In response to the growing demand for biomedical implants with improved durability and biocompatibility, the objective was to develop coatings that enhance both wear and corrosion resistance in physiological environments. The effects of silver incorporation and oxygen concentration on the structural, tribological, and electrochemical behavior of the coatings were systematically analyzed. X-ray diffraction (XRD) was employed to identify crystalline phases, while atomic force microscopy (AFM) was used to characterize surface topography prior to wear testing. Wear resistance was evaluated using a ball-on-plane tribometer under simulated prosthetic motion, applying a 5 N load with a bone pin as the counter body. Corrosion resistance was assessed through electrochemical impedance spectroscopy (EIS) in a physiological solution. Additionally, tribocorrosive performance was investigated by coupling tribological and electrochemical tests in Ringer’s lactate solution, simulating dynamic in vivo contact conditions. The results demonstrate that Ag doping, combined with increased oxygen content in the sputtering atmosphere, significantly improves both wear and corrosion resistance. Notably, the ZrO₂-Ag coating deposited with 50% O₂ exhibited the lowest wear volume (0.086 mm³) and a minimum coefficient of friction (0.0043) under a 5 N load. This same coating also displayed superior electrochemical performance, with the highest charge transfer resistance (38.83 kΩ·cm²) and the lowest corrosion current density (3.32 × 10⁻⁸ A/cm²). These findings confirm the high structural integrity and outstanding tribocorrosive behavior of the coating, highlighting its potential for application in biomedical implant technology. Full article

Background and Clinical Significance: Prosthetic rehabilitation in the aesthetic zone of periodontally compromised patients presents a complex clinical challenge, requiring a careful coordination of aesthetic, functional, and biological demands. This case highlights the benefits of digital dentistry, interdisciplinary collaboration, and regular maintenance in achieving long-term success in complex rehabilitations of periodontally compromised patients. Case Presentation: This case report describes the digital minimally invasive rehabilitation of a 39-year-old male patient with Stage III periodontitis, occlusal discrepancies, tooth mobility, and an interincisal diastema. A fully digital workflow—including intraoral scanning, aesthetic previewing, and mandibular motion analysis—was employed to guide diagnosis, treatment planning, and prosthetic execution. Conservative tooth preparations using a biologically oriented approach (BOPT) were combined with customised provisional restorations to support soft tissue conditioning and functional control throughout the provisional phases. Mandibular motion tracking facilitated the design of a personalised anterior guidance to improve occlusion and correct the deep bite. The interincisal diastema was initially maintained then closed during the advanced phase of treatment based on aesthetic simulations and patient preference. One unplanned endodontic treatment was required during the provisional phase, but no other complications occurred. Conclusions: At the four-year follow-up, the patient demonstrated stable periodontal and occlusal conditions, improved clinical indices, and high satisfaction with the aesthetic outcome. Full article

Background: In recent decades, aortic valve surgery has transitioned from conventional median sternotomy (MS) to minimally invasive techniques, including partial upper mini-sternotomy (PUMS) and right anterolateral mini-thoracotomy (RAMT). This study retrospectively compares the outcomes of aortic valve replacement (AVR) using PUMS during the learning phase with those of standard MS. Methods: A retrospective analysis was conducted on patients (n = 211) who underwent AVR for aortic stenosis. They were divided into MS (n = 119) and PUMS (n = 92) groups. Various preoperative, surgical and postoperative parameters, including survival, were examined. Results: Preoperatively, the main difference was age, with PUMS patients being older (67.5 ± 7 vs. 66.5 ± 9.6; p = 0.010). PUMS patients also had longer cardiopulmonary bypass (CPB) and cross-clamping times (99 ± 25 vs. 80 ± 16 min; p < 0.002; 79 ± 18 vs. 65 ± 13 min; p < 0.024). There were no significant differences in body mass index, prosthesis size, indexed effective orifice area, hospitalisation duration or any other monitored parameter. Echocardiographic follow-up found no differences in prosthetic pressure gradients, flow velocity or paravalvular leak between the PUMS and MS groups. Survival rates were similar over 1000 days. Conclusions: The data suggest that PUMS offers comparable surgical outcomes to MS for AVR with additional cosmetic benefits, undeterred by a learning curve. Full article

Introduction: Pediatric prosthetic knee joints must be appropriately scaled from adult designs to ensure proper gait biomechanics. However, direct dimensional scaling without considering the biomechanical implications may lead to functional discrepancies. This study aimed to evaluate whether using a linear scaling factor can effectively adapt a knee for pediatric use. The study assessed whether such an approach yields a viable pediatric prosthetic knee joint by applying a fixed scaling factor and analyzing the resultant knee geometry. Methods: The linear scaling factor was determined based on the pylon tube diameter, a key constraint in compact pediatric knee design. Given a pediatric pylon diameter of 22 mm, the length of the tibial link was set to 22 mm, yielding a scaling factor of 0.6875 when compared to the adult-sized knee. This scaling factor was used to determine the dimensions of the pediatric four-bar (scaled) knee joint. Static geometric analysis was conducted using GeoGebra^® to model the lower-body segment lengths. The knee joint’s performance was evaluated based on stance and swing phase parameters. These metrics were compared between the scaled knee and a commercial pediatric knee. Results: The geometric analysis revealed that while using the linear scaling factor maintained proportional relationships, certain biomechanical parameters deviated from the expected pediatric norms. The scaled knee achieved a toe clearance of 13.5 mm compared to 19.7 mm in the commercial design and demonstrated a swing-phase heel clearance of 11.6 mm versus 13.3 mm, maintaining negative x/y ratios at heel contact and showing significant stability in push-off moments, while the stance flexion angle remained within an acceptable range. The heel contact and push-off ratios (x/y) were found to be comparable, with the scaled model achieving values of −1.21 and −0.59, respectively. The stance flexion angle measured 10.6°, closely aligning with the commercial reference. Conclusions: Using a linear scaling factor provides a straightforward method for adapting adult prosthetic knee designs to pediatric use. However, deviations in key biomechanical parameters indicate that further experimental study may be required to validate the applicability of the scaled knee joint for pediatric users. Future work should explore dynamic simulations and experimental validations to refine the design further and ensure optimal gait performance. Full article

Background/Objectives: In the setting of breast surgery, indocyanine green angiography (ICGA) allows estimating the perfusion of cutaneous tissues during surgical interventions, in order to reduce vascularization-related complications. This study has a dual objective: to evaluate the correlation between preoperative factors and the level of skin vascularization, measured by ICGA, in patients undergoing subcutaneous mastectomy for breast cancer; and to establish any relationship between low intraoperative vascularization and the onset of postoperative complications. Methods: This is a preliminary, non-randomized, prospective clinical study that includes 46 female patients undergoing subcutaneous mastectomy with reconstruction for breast cancer between February 2022 and July 2024. The relationship between vascularization and the following preoperative variables was assessed: smoking, previous breast surgeries, prior radiotherapy, neoadjuvant or prior chemotherapy/anti-Her2 therapy, and the thickness of breast subcutaneous tissue evaluated through mammography. For the analysis, three ICGA procedures were performed, using 0.125 mg/kg of indocyanine green (ICG) for each procedure before the surgical incision (V1), at the end of the demolition phase (V2), and at the end of the reconstruction phase (V3). The results of this analysis were finally correlated with the occurrence of any postoperative complications. Results: Vascularization was conventionally classified as “low” and “good” using a cutoff of 33%. Previous surgeries on the ipsilateral breast and neoadjuvant or prior chemotherapy/anti-Her2 therapy were found to be predictive factors of “low” vascularization (p = 0.031). Patients with “low” vascularization at time V3 showed a significantly higher risk of developing complications (p = 0.038). Incision length emerged as an independent predictor of complications, with a 23% increase in risk per additional centimeter (p = 0.006), independent of perfusion level. Conclusions: This study supports the use of ICGA as a useful tool to improve outcomes in patients undergoing subcutaneous mastectomy with prosthetic reconstruction for breast cancer. The results of this preliminary work are encouraging, and recruiting a larger number of patients could provide more significant data. Full article

Background/Objectives: Semi-active prosthetic feet present a promising solution that enhances adaptability while maintaining modest size, weight, and cost. We propose a semi-active Two-Keel Variable-Stiffness Foot (VSF-2K), the first prosthetic foot where both the hindfoot and forefoot stiffness can be independently and actively modulated. We present a model-based analysis of the effects of different VSF-2K settings on prosthesis characteristics and gait metrics. Methods: The study introduces a simulation model for the VSF-2K: (1) one sub-model to optimize the design of the keels of VSF-2K to maximize compliance, (2) another sub-model to simulate the stance phase of walking with different stiffness setting pairs and ankle alignment angles (dorsiflexion/plantarflexion), and (3) a third sub-model to simulate the keel stiffness of the hindfoot and forefoot keels comparably to typical mechanical testing. We quantitatively analyze how the VSF-2K’s hindfoot and forefoot stiffness settings and ankle alignments affect gait metrics: Roll-over Shape ($ROS$), Effective Foot Length Ratio ($EFLR$), and Dynamic Mean Ankle Moment Arm ($DMAMA$). We also introduce an Equally Spaced Resampling Algorithm (ESRA) to address the unequal-weight issue in the least-squares circle fit of the Roll-over Shape. Results: We show that the optimal-designed VSF-2K successfully achieves controlled stiffness that approximates the stiffness range observed in prior studies of commercial prostheses. Our findings suggest that stiffness modulation significantly affects gait metrics, and it can mimic or counteract ankle angle adjustments, enabling adaptation to sloped terrain. We show that $DMAMA$ is the most promising metric for use as a control parameter in semi-active or variable-stiffness prosthetic feet. We identify the limitations in $ROS$ and $EFLR$, including their nonmonotonic relationship with hindfoot/forefoot stiffness, insensitivity to hindfoot stiffness, and inconsistent trends across ankle alignments. We also validate that the angular stiffness of a two-independent-keel prosthetic foot can be predicted using either keel stiffness from our model or from a standardized test. Conclusions: These findings show that semi-active variation of hindfoot and forefoot stiffness based on single-stride metrics such as $DMAMA$ is a promising control approach to enabling prostheses to adapt to a variety of terrain and alignment challenges. Full article

Background: The literature reports few instances of spontaneous bowel eviscerations through umbilical hernia sites. Spontaneous rupture of the hernia sac is a less common complication, primarily associated with persistent ascites or congenital wall defects. Materials and methods: A systematic review was conducted using the PubMed database—the United States National Library of Medicine, with the search terms “spontaneous bowel evisceration” and “umbilical hernia evisceration”. However, several results were deemed unsuitable for this manuscript. From a total of 185 cases, this review was narrowed down to 9 usable reports. Non-English language cases, duplicates, and cases unrelated to the pathology, including pediatrics, malformations, herniation through other organs, and animal cases, were excluded. Conclusions: Spontaneous evisceration in a hernia is an uncommon yet serious condition. A major risk factor appears to be underlying liver disease with its complications, such as ascites, chronic malnutrition with hypoalbuminemia, and collateral circulation formation. These factors contribute to the susceptibility of the sac and the hernia wall to rupture. However, the limited number of reported cases precludes the establishment of a preferred treatment approach. In the acute phase, the use of prosthetics may be less advisable, but in an elective setting, the cirrhotic patient could be offered repair. Full article

The development of prosthetic limbs has benefited individuals who suffered amputations due to accidents or medical conditions. During the development of conventional prosthetics, several challenges have been observed regarding the functional limitations, the restricted degrees of freedom compared to an actual human limb, and the biocompatibility issues between the surface of the prosthetic limb and the human tissue or skin. These issues could result in mobility impairments due to failed mimicry of the actual stress distribution, causing discomfort, chronic pain, and tissue damage or possible infections. Especially in cases where underlying conditions exist, such as diabetes, possible trauma, or vascular disease, a failed adaptation of the prosthetic limb could lead to complete abandonment of the prosthetic part. To address these challenges, the insertion of topologically optimized parts with a biomimetic approach has allowed the optimization of the mimicry of the complex functionality behavior of the natural body parts, allowing the development of lightweight efficient anthropomorphic structures. This approach results in unified stress distribution, minimizing the practical limitations while also adding an aesthetic that aids in reducing any possible symptoms related to social anxiety and impaired social functioning. In this paper, the development of a novel anthropomorphic designed prosthetic foot with a novel Thermoplastic Polyurethane-based composite (TPU-Ground Tire Rubber 10 wt.%) was studied. The final designs contain advanced sustainable polymeric materials, gyroid lattice geometries, and Finite Element Analysis (FEA) for performance optimization. Initially, a static evaluation was conducted to replicate the phenomena at the standing process of a conventional replicated above-knee prosthetic. Furthermore, dynamic testing was conducted to assess the mechanical responses to high-intensity exercises (e.g., sprinting, jumping). The evaluation of the dynamic mechanical response of the prosthetic limb was compared to actual plantogram-derived foot pressure data during static phases (standing, light walking) and dynamic phenomena (sprinting, jumping) to address the optimal geometry and density, ensuring maximum compatibility. This innovative approach allows the development of tailored prosthetic limbs with optimal replication of the human motion patterns, resulting in improved patient outcomes and higher success rates. The proposed design presented hysteretic damping factor and energy absorption efficiency adequate for load handling of intense exercises (0.18 loss factor, 57% energy absorption efficiency) meaning that it is suitable for further research and possible upcycling. Full article

Lower limb motion recognition using surface electromyography (EMG) enhances human-computer interaction for intelligent prostheses. This study proposes a surface electromyography (EMG)-based scheme for lower limb motion recognition to enhance human-computer interaction in intelligent prostheses. Addressing the loss of phase information in existing methods, the approach combines S-transform energy concentration and multi-channel fusion analysis. EMG signals from six lower limb muscles of 10 subjects performing four movements (level walk, stair ascent, stair descent, and obstacle crossing) were analyzed. Correlation analysis identified the most relevant and least correlated muscles, optimizing signal quality. Using support vector machines (SVM), motion recognition accuracy was evaluated for single-channel and multi-channel signals. Results indicated that the semi-tendon and rectus femoris muscles achieved 80.71% accuracy with simple time-frequency features, while the medial gastrocnemius and rectus femoris reached 93.70% accuracy with S-transform energy concentration. Multi-channel fusion (rectus femoris, biceps femoris, and medial gastrocnemius) based on S-transform achieved over 96% accuracy, demonstrating superior recognition performance and potential for improving adaptive human-robot interaction in prosthetic control. Full article

Introduction: Additive manufacturing has emerged as a promising solution for improving the accessibility and affordability of upper limb prostheses. Despite the growing need, traditional prosthetic devices remain costly and often inaccessible, particularly in underserved regions. This review examines the current landscape of 3D-printed upper limb prostheses, focusing on their design, functionality, and cost-effectiveness. It aims to assess the potential of 3D-printing upper limb prostheses in addressing current accessibility barriers. Methods: A two-phase approach was used to analyze the literature on 3D-printed upper limb prostheses. The first phase involved a literature search using keywords related to 3D printing and upper limbs prostheses. The second phase included data collection from online platforms such as Enabling the Future, Thingiverse, and NIH 3D Print Exchange. Studies focusing on the design, fabrication, and clinical application of 3D-printed prostheses were included. The results were organized into categories based on design characteristics, kinematic features, and manufacturing specifications. Results: A total of 35 3D-printed upper limb prostheses were reviewed, with the majority being hand prostheses. Devices were categorized based on their range of motion, actuation mechanism, materials, cost, and assembly complexity. The e-NABLE open-source platform has played a significant role in the development and dissemination of these devices. Prostheses were classified into cost categories (low, moderate, and high), with 64% of models costing under USD 50. Most designs were rated as easy to moderate in terms of assembly, making them accessible for non-specialist users. Conclusions: Three-dimensional printing offers an effective, low-cost alternative to traditional prosthetic manufacturing. However, variability in design, a lack of standardized manufacturing protocols, and limited clinical validation remain challenges. Future efforts should focus on establishing standardized guidelines, improving design consistency, and validating the clinical effectiveness of 3D-printed prostheses to ensure their long-term viability as functional alternatives to traditional devices. Full article

Integrating machine learning into additive manufacturing offers transformative opportunities to optimize material properties and design high-performance, fatigue-resistant structures for critical applications in aerospace, biomedical, and structural engineering. This study explores mechanistic machine learning techniques to tailor microstructural features, leveraging data from ultrasonic fatigue tests where very high cycle fatigue properties were assessed up to $1\times {10}^{10}$ cycles. Machine learning models predicted critical fatigue thresholds, optimized process parameters, and reduced design iteration cycles by over 50%, leading to faster production of safer, more durable components. By refining grain orientation and phase uniformity, fatigue crack propagation resistance improved by 20–30%, significantly enhancing fatigue life and reliability for mission-critical aerospace components, such as turbine blades and structural airframe parts, in an industry where failure is not an option. Additionally, the machine learning-driven design of metamaterials enabled structures with a 15% weight reduction and improved yield strength, demonstrating the feasibility of bioinspired geometries for lightweight applications in space exploration, medical implants, and high-performance automotive components. In the area of titanium and aluminum alloys, machine learning identified key process parameters such as temperature gradients and cooling rates, which govern microstructural evolution and enable fatigue-resistant designs tailored for high-stress environments in aircraft, biomedical prosthetics, and high-speed transportation. Combining theoretical insights and experimental validations, this research highlights the potential of machine learning to refine microstructural properties and establish intelligent, adaptive manufacturing systems, ensuring enhanced reliability, performance, and efficiency in cutting-edge engineering applications. Full article

The design of prosthetic hands presents inherent complexities and contradictions that require careful resolution during the initial design phase to achieve a functional solution. This study simplifies prosthetic hand design through an in-depth analysis of the two degrees of freedom (DoF) metacarpophalangeal (MCP) joint, critical in enabling versatile grasping capabilities. Optimal palmar finger orientations were devised using performance metrics, enabling each finger to have 3 DoF while maintaining a simplified mechanical structure. The proposed palmar configuration demonstrated significantly improved grasping performance compared to conventional parallel-fingered designs, accommodating objects of diverse shapes and sizes. A preliminary 3D printed prototype was developed and tested to validate the design. The prototype successfully demonstrated its ability to grasp a wide range of objects, substantiating the efficacy of the novel palmar configuration. This innovative design reduces mechanical complexity without compromising dexterity or functionality. It represents a transformative approach to prosthetic hand development, aligning with the principal goal of enabling users to perform activities of daily living effectively. The findings of this work introduce a novel paradigm in prosthetic hand design, offering a balanced combination of efficiency, dexterity, and practical applicability, thereby advancing the state-of-the-art in prosthetic technology. Full article

Background: Breast cancer comprises diverse subtypes with prognostic and therapeutic implications. Hormone therapy plays a crucial role in managing tumors expressing hormonal receptors, but its impact on breast reconstruction outcomes remains unclear. This study aims to evaluate the association between perioperative hormone therapy continuation and the incidence of postoperative complications following breast reconstruction (including autologous, prosthetic, and hybrid techniques), with a focus on identifying specific complication types to refine patient management strategies. Methods: A retrospective analysis was conducted on patients who underwent breast reconstruction following mastectomy for hormone receptor-positive breast cancer. Patients were categorized based on the appropriate discontinuation of hormonal therapy. Clinical data, including patient characteristics, treatment regimens, and complication occurrences, were registered and analyzed. Results: Inadequate suspension of hormonal therapy during the perioperative period was significantly associated with a higher rate of complications, particularly in the immediate and early phases. Complications such as skin alterations, flap failure, seroma development, and clinical infection showed significant associations with the continuation of hormone therapy (p < 0.05). No significant differences were observed for other complications. Conclusions: Preliminary findings suggest a potential correlation between the continuation of hormone therapy during the perioperative phase and the development of complications following breast reconstruction. Full article

Background: This descriptive study aimed to assess the survival rates and outcomes of dental implants in one of the four national HMOs in Israel. Data are provided for the period from 1 January 2014 to 31 December 2022. Materials and Methods: This retrospective analysis utilized electronic medical records of patients who underwent dental implant placement during the specified period. Statistical analyses included chi-squared tests, Student’s t-tests, and generalized estimating equation (GEE) analyses to identify potential risk factors associated with early and late implant failures. Results: A total of 158,824 dental implants were placed in 53,874 patients. The overall implant failure rate was 2.21%, while the early failure rate during the osseointegration phase—before prosthetic reconstruction—was 1.56%. Significant associations with implant failure were observed for male patients (2.53% failure rate), implants in the maxillary molar region (3%), and the central incisor region (3.37%), approximately double the failure rates seen in other implant sites (p < 0.001). Conclusions: This extensive data analysis demonstrates a low overall failure rate for dental implants. The highest failure incidence occurred within the first year post-implantation, declining in subsequent years irrespective of rehabilitation status. Early failure risk factors differ based on various factors and should be carefully integrated into presurgical planning. Full article