Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine最新文献

With the rapid development of medical imaging technology, computer-assisted dynamic intraoperative navigation (CADIN) technology has been introduced into the field of oral and maxillofacial surgery due to its technological features of accurately localizing key anatomical structures during surgery. Registration is a key step in CADIN technology. In different application scenarios, the choice of the registration method directly determines the accuracy of the navigation feedback, which in turn affects the effectiveness and safety of the entire surgery. In this paper, by searching and analyzing the database of articles on the application of CADIN technology in the field of oral and maxillofacial surgery for the years 2019-2025. The inclusion criteria are the application, optimization and system design of CADIN technology in oral and maxillofacial surgery. After screening 1069 articles, 42 articles were finally included. An analysis of the articles included in the study revealed that trauma and facial reconstruction guided by CADIN technology are hot research topics in the field of CADIN technology in oral and maxillofacial surgery. There are few reports on the use of CADIN technology to guide the endodontic treatment. In addition, the largest number of studies performed the registration process using the markerless. A review of the literature reveals that CADIN technology has great potential for practical clinical application in the field of oral and maxillofacial surgery and that the selection of appropriate registration methods can improve the accuracy of oral and maxillofacial surgical procedures.

According to the Global Cancer Observatory of the International Agency for Research on Cancer (IARC), Asian countries have a high incidence, mortality, and prevalence rate of cancer among other countries. Owing to the complexity and different stages of cancer, treating cancer remains difficult. Chemotherapy is a conventional strategy used to treat cancer, along with surgery, immunotherapy, and radiotherapy. Chemotherapeutic agents are effective in killing cancer cells; however, they also cause various side effects, such as fatigue and high systemic toxicity. To address this issue, nanomedicine plays a crucial role in developing externally stimuli-responsive smart nanocarriers to enhance cancer treatment. Among the various types of therapies, photothermochemotherapy (PTC) is one of the most effective ways to treat cancer where nanocarriers are designed to release drugs through NIR light-induced hyperthermia in the tumor microenvironment. Gold nanoparticles (AuNPs) are the best photosensitizers that convert near-infrared (NIR) light into heat and are used to fabricate PTC nanocarriers. In addition to AuNPs, other materials have been used to fabricate PTC nanocarriers to enhance various properties, such as drug loading efficiency and targetability. This review systematically examines a broad spectrum of gold-based nanocarriers, including structurally modified AuNPs and composite formulations incorporating metal, polymer, carbon, hydrogel, lipid, hybrid, and mesoporous silica components, all of which are engineered to enhance cancer cell ablation through synergistic PTC.

In recent years, various implant and filler materials have been used depending on the necessity of application in different parts of the human body. The biomaterial used in the living body must have adequate mechanical, esthetic, and chemical behavior throughout the treatment process. For this reason, researchers are developing many test methods to predict the behavior of biomaterials placed in the human body over time. This study aims to analyze the chewing simulation test methods and the mechanical behavior of composite materials used as filler biomaterials in the treatment process in recent years. Also, in vitro and 3D finite element analysis methods of composite materials with different filler structures were evaluated for the chewing simulation test process. Biomaterials implanted in the human body can be subjected to continuous and complex damage mechanisms. For this reason, the ability to model the behavior of the chewing simulation test method parameters performed in the laboratory environment on living tissue is important. In addition, the inadequate mechanical behavior of the composite biomaterial may lead to unsatisfactory treatment processes. Overall, understanding the fatigue and wear behavior of composite materials during chewing plays an important role in predicting in vivo results. This result is seen as an important key in improving the mechanical and esthetic behavior of composite materials over time.

Due to crown overlap and insufficient scanner resolution, 3D tooth model obtained from intraoral scans often exhibit inter-tooth adhesion, resulting in loss of individual tooth interproximal morphology and blurred interdental spaces, which severely compromises the accuracy and efficacy of orthodontic treatment. Existing reconstruction methods rely heavily on manual intervention, limiting their clinical efficiency. To address this, we propose a fully automated database-driven framework that reconstructs missing tooth morphology through parametric template retrieval and deformation. Our method first constructs a parametric tooth database using multi-view convolutional neural networks (MVCNN), encoding 3D morphology into discriminative feature descriptors. A coarse-to-fine localization strategy enables fully automated localization with sub-millimeter accuracy. Missing morphology are then restored via iterative Laplacian deformation with weight constraints, while parametric B-spline modeling reconstructs root anatomy. Validation on clinical cases, our method achieved a root mean square surface distance of less than 0.096 mm, outperforming state-of-the-art approaches. The results demonstrate that our framework enables efficient and precise fully automated tooth reconstruction, offering a clinically viable solution for digital orthodontics.

Disturbance in the visual system is directly related to dysfunction in walking. This study investigated the independent and interactive effects of two paving designs (common vs standard (ISO 23599)) and two white cane lengths (standard vs extended) on walking performance. Twenty individuals with congenital blindness performed four walking experiments in a 2 × 2 within-subjects factorial design. Key gait and balence parameters were measured using Kinovea software and a trunk accelerometer. A two-way repeated measures multivariate analysis of variance (RM-MANOVA) was applied to the data. While the overall multivariate test for an interaction effect was not statistically significant (p = 0.146), the univariate tests revealed a strong synergistic effect for key gait parameter. Specifically, a significant interaction was found for speed (p = 0.009), stride length (p = 0.008), and step length (p = 0.032). The benefit of standard paving on these variables was substantially greater when participants used an extended cane. A significant multivariate main effect was also found for paving type (p = 0.002). Optimal walking performance for visually impaired individuals is best achieved through a synergistic combination of assistive tools and environmental design. Our findings indicate that the simultaneous use of an extended white cane and standardized tactile paving yields the greatest improvements in key gait patterns like speed and stride length. This highlights that mobility strategies should focus on integrating the tool and the environment to maximize safety and efficiency.

With the advancement of minimally invasive spinal surgery, pedicle screw fixation is a key approach for spinal disease treatment. However, achieving reliable fixation in osteoporotic bone remains challenging. This study evaluates the pullout performance of eight pedicle screw types across different bone densities using 3D-printed screws and rigid polyurethane foam models. Pullout strength, equivalent force, and maximum deflection were assessed via mechanical testing and finite element analysis. Cement-Augmented (CA) and Expandable (EPS) screws exhibited superior pullout resistance in osteoporosis, while Double Pitch (DP) and Double Threaded (DT) screws performed best in healthy bone, and Double Double Core (DDC) and New Double Threaded (NDT) screws excelled in osteopenia. Finite element results closely matched experimental data, confirming reliability. The findings highlight the significant influence of bone density on screw fixation and provide guidance for clinical selection. Future research will focus on novel screw designs to enhance surgical outcomes.

This study aimed to assess surface alterations of two nickel-titanium files with different cross-sections, before and after multiple uses, using Scanning Electron Microscopy (SEM). A total of 120 S-shaped artificial canals were used to examine the surface alterations of X-Never Break X2 (EasyInSmile International Corp., Changsha, China) (n = 10) and JIZAI I (Mani, Tochigi, Japan) (n = 10) files. These changes were analyzed using SEM before use and after the first, third, and sixth use. The files underwent sterilization and cleaning after each use, and surface alterations such as microcracks, tip deformation, surface pitting, and debris were observed. SEM images were captured at different magnifications (×100, ×250, ×500, and ×1000) before and after use. These images were examined by two independent observers to assess the presence of deformations and debris on their surfaces. Both files showed a proportional increase in surface alterations with the number of uses. While microcracks and tip deformation were more prominent in the X-Never Break X2 files with continued use compared to the JIZAI I files, surface pitting was more frequently observed in the JIZAI I files. The significant increase in surface alterations after the third use suggests that continuing to use the files beyond this point could potentially lead to fractures. These surface alterations were more pronounced in the X-Never Break X2 group compared to the JIZAI I group.

The aim of the study was to develop a method to assess loading rate in the frequency domain using accelerometry, and to examine how the frequency-domain loading rate changes with body location and relates to time-domain loading rate during walking. A method was developed to calculate loading rate from acceleration signal by decomposing active motion and impact loading components in the signal into different frequency bands. The method was used to analyse an open access dataset consisting of acceleration and ground reaction force data of human walking. Acceleration data measured at pelvis, thigh, shanks, and feet during walking were used to obtain loading rate at four frequency bands: 0-3, 3-6, 6-10, and 10-15 Hz. Ground reaction forces were analysed to obtain time-domain loading rate measurements, including Average Loading Rate (ALR) and Instantaneous Loading Rate (ILR). Loading rate at all four frequency bands was attenuated significantly from foot to pelvis (p < 0.001). However, the pattern of attenuation was different at low frequency bands (below 10 Hz) compared to high frequency bands (above 10 Hz). Loading rate measured at body segments in the frequency domain was significantly correlated with ALR and ILR (R² from 0.44 to 0.56). However, the strength of correlation was higher in low frequency bands (below 10 Hz) than high frequency bands (above 10 Hz). The study suggests that assessing loading rate in the frequency domain can provide additional insights into the load experienced by specific body segments in human locomotion.

Radiofrequency ablation (RFA) is a commonly used technique for the treatment of hepatocellular carcinoma. However, current techniques still face issues with incomplete ablation, local tumor recurrence, or excessive ablation that causes damage to normal tissues. This study aims to compare the ablation effects of traditional constant-power RFA (TCP-RFA) and boundary temperature-controlled RFA (BTC-RFA) conditions in an ex vivo bovine liver under water-cooling equipment. Additionally, it seeks to optimize the parameters of the BTC-RFA algorithm to improve the precision of ablation. The proportion of damage area (PDA) were evaluated by ImageJ software and statistical analysis was performed on the experimental results. Results indicated that BTC-RFA mode significantly reduced the PDA compared to TCP-RFA. Optimal ablation was achieved with 45 W initial power, a temperature control range of 55°C-65°C, and a 10°C temperature control step, demonstrating BTC-RFA's superiority in achieving precise and effective tumor ablation. This study confirmed the effectiveness of the BTC-RFA algorithm, which can achieve complete ablation of tumor tissue while significantly reducing damage to non-targeted normal tissues.

As the field of prosthetics moves away from traditional subtractive manufacturing methods toward more sustainable, customizable approaches like 3D printing, this study examines how varying clearance values in cycloidal drives impact their vibrational behavior. Cycloidal drives known for their high torque density and low backlash, are gaining traction as key reduction components in robotic prostheses, where minimizing vibration is essential for ensuring smooth gait transitions, reducing user fatigue, and improving long-term prosthetic wear comfort. This study investigates the vibrational performance of 3D-printed cycloidal drives by evaluating different clearances to optimize vibrational performance in robotic prostheses applications, specifically in robotic knee joints. In this research, three clearance values (0.2, 0.3, and 0.5 mm) were tested on a benchtop using 3D-printed cycloidal drives. With the retrieved raw gyroscope data, a combination of ANOVA and time-frequency analyses was employed to evaluate their vibrational performance across different speeds and load conditions. The study revealed that the 0.2 mm clearance, while effective at higher speeds, exhibited greater variance, and concentrated vibrational energy at lower speeds, which could cause localized stress and wear. The 0.3 mm clearance emerged as the most balanced, with minimal variance, evenly distributed vibrational energy, and greater durability, making it ideal for high-precision applications like prosthetic joints. In contrast, the 0.5 mm clearance exhibited erratic behavior, with excessive vibration and mechanical noise, making it the least favorable option.