Prosthetic Design Research Articles

AI in Prosthodontics: A Narrative Review Bridging Established Knowledge and Innovation Gaps Across Regions and Emerging Frontiers

As the discipline of prosthodontics evolves, it encounters a dynamic landscape characterized by innovation and improvement. This comprehensive analysis underscores future developments and transformative solutions across its various subspecialties: fixed, removable, implant, and maxillofacial prosthodontics. The narrative review examines the latest advancements in prosthetic technology, focusing on several critical areas. The integration of artificial intelligence and machine learning into prosthetic design and fitting processes is revolutionizing the field, serving as a common thread that links these innovative technologies across all subspecialties. This includes advancements in automated diagnostics, predictive analysis, and treatment planning. Furthermore, the review offers a forward-looking perspective on how these innovations are influencing each prosthetic dentistry domain, patient outcomes, and current clinical practices. By thoroughly analyzing contemporary research and emerging technologies, the study illustrates how these advancements represent a growing focal point of interest in developing countries, such as Romania, with the potential to redefine the trajectory of prosthetic rehabilitation and enhance patient care not only within this country but also beyond.

DIRECT ANTERIOR SURGICAL APPROACH FOR TOTAL HIP ARTHROPLASTY AS AN ALTERNATIVE TO THE DIRECT LATERAL APPROACH

The frequency of total hip arthroplasty (THA) is continuously increasing. Currently, efforts are underway to improve the efficiency of this surgery, making the choice of surgical approach a key factor in its success. The direct anterior approach is gaining popularity due to faster patient recovery, but its advantages and disadvantages compared to the direct lateral approach are not yet fully understood. Objective. To compare the outcomes of the direct anterior and direct lateral approaches in primary total hip arthroplasty, as well as to identify ways to improve the results of THA performed using the direct anterior approach. Methods. A literature search was conducted in three bibliographic databases: PubMed, Scopus, and Web of Science. Results. The direct anterior approach has been found to reduce postoperative pain, blood loss, the likelihood of periprosthetic infection, and hospital stay duration. However, there is an increased risk of dislocation and revision surgery. Several randomized controlled trials have been cited, studying issues related to effective pain management, wound healing, prevention of lateral femoral cutaneous nerve injury, blood loss, prosthetic stem design, specific surgical techniques, equipment selection, early mobilization after THA, and the use of modern software for THA planning. Conclusions. The literature review revealed that patients who underwent THA via the direct anterior approach experienced less postoperative pain. The shorter incision associated with this approach also reduces intraoperative blood loss and periprosthetic infection rates. However, the risk of dislocation and subsequent revision surgeries increases, as does the incidence of nerve paralysis due to lateral femoral cutaneous nerve injury.

A Review of Myoelectric Prosthetic Arm Designs from 2011 to 2022

Prosthetic arms are worn by people whose arms have been amputated. Amputation involves surgical removal of the muscle, neurosensory system, and skeletal system. Myoelectric prosthetics make use of the signals generated by the intact muscles for the limb movement. Prosthetic limbs are designed using mechanical parts with suitable gear and motors. Users of prosthetic arms can carry out tasks associated with everyday living and their jobs almost exactly like they would with a natural arm. Prosthetic arms come in a variety of designs based on the needs of the user. The current research reviews the goals, plans, and trials conducted on prosthetic elbows, wrists, and hands between 2011 and 2022 from reputable conferences and journals. In this work, the design of two prosthetic hands with one degree of freedom and thirteen degrees of freedom, respectively, in the 3D simulation tool SolidWorks is described. Prosthetic elbow and a wrist with one degree of freedom were designed as well. The fine motor activities can be performed with the prosthetic fingers designed in this work.

Evaluating the Effectiveness of Transtibial Prosthetic Socket Shape Design Using Artificial Intelligence: A Clinical Comparison With Traditional Plaster Cast Socket Designs

ObjectiveTo investigate the feasibility of creating an artificial intelligence (AI) algorithm to enhance prosthetic socket shapes for transtibial prostheses, aiming for a less operator-dependent, standardized approach. DesignThe study comprised 2 phases: first, developing an AI algorithm in a cross-sectional study to predict prosthetic socket shapes. Second, testing the AI-predicted digitally measured and standardized designed (DMSD) prosthetic socket against a manually measured and designed (MMD) prosthetic socket in a 2-week within-subject cross-sectional study. SettingThe study was done at the rehabilitation department of the Radboud University Medical Center in Nijmegen, the Netherlands. ParticipantsThe AI algorithm was developed using retrospective data from 116 patients from a Dutch orthopedic company, OIM Orthopedie, and tested on 10 randomly selected participants from Papenburg Orthopedie. InterventionsUtilization of an AI algorithm to enhance the shape of a transtibial prosthetic socket. Main Outcome MeasuresThe algorithm was optimized to minimize the error in the test set. Participants’ socket comfort score and fitting ratings from an independent physiotherapist and prosthetist were collected. ResultsPredicted prosthetic shapes deviated by 2.51 mm from the actual designs. In total, 8 of 10 DMSD and all 10 MMD-prosthetic sockets were satisfactory for home testing. Participants rated DMSD-prosthetic sockets at 7.1 ± 2.2 (n=8) and MMD-prosthetic sockets at 6.6 ± 1.2 (n=10) on average. ConclusionsThe study demonstrates promising results for using an AI algorithm in prosthetic socket design, but long-term effectiveness and refinement for improved comfort and fit in more deviant cases are necessary.

Carrying angle among young adults of Saudi Arabia and its correlation with demographic characteristics: A cross sectional study.

The angle between the median axes of the forearm and arm is called the carrying angle (CA). Sex differences in CA and its relation to age, height, weight, and BMI are unclear. The aim of the present study was to measure the CA in male and female subjects in the Saudi population and correlate it with the above variables. A digital goniometer was used to measure CA in 181 males and 165 females. Information on age, height, weight, and BMI was also recorded. CA showed differences based on sex, though was independent of age, height, weight, and BMI. Hormonal factors may influence CA and could explain larger CA values in female subjects. CA measurement in specific population groups contributes to the successful management of several pathological conditions of the elbow and aids in the design of elbow orthotics and prosthetics.

Quality of Communication between Dental Technicians and Dentists during the Fabrication of Removable Partial Dentures in Casablanca, Morocco

Introduction: Communication between the dentist and the dental laboratory technician plays an essential role in the success of prosthetic treatment. The purpose of this study was to describe the quality of communication between dentist and dental technicians, and to highlight the different constraints encountered by the laboratory technician when making removable partial prostheses. Materials and Methods: This is a cross-sectional study conducted among 94 dental technician working in the private sector in Casablanca. To collect data an auto administrated questionnaire was distributed to the dental technicians. This tool included five sections : Identification, communication methods, prosthetic design, communication difficulties and the added value of digitizing the prosthetic chain. Data were statistically processed using SPSS 20 software. Results: A total of 94 dental technicians working in Casablanca were interviewed. All these laboratory technicians (100%) used the laboratory form as their main means of communication. Additional means of communication were used to complete missing information (phone, photo sharing, e-mail). 72.3% of dental technicians designed the metal framework for cast partial dentures themselves and 67% of prosthetists said that digitizing the prosthetic chain could improve dentist - dental laboratory technician communication. Conclusion: Effective communication between dentist and dental technician is essential for successful prosthetic treatment and patient satisfaction

A dataset of optical camera and IMU sensor derived kinematics of thirty transtibial prosthesis wearers

Motion analysis has played a crucial role in providing gait analysis for prosthetic users. Understanding kinematics in motion analysis allows for the evaluation of the effects of prostheses and the development of a prosthetic component design that aids in walking within the community. However, there are currently limited open datasets available to study the locomotion of individuals using transtibial prostheses, and most research studies involve a limited number of participants. This dataset shows 30 transtibial prosthesis users walking comfortably on a 10-meter walkway inside a laboratory. We offer a set of joint ankles obtained from the inertial measurement unit (IMU) signals in CSV file format. We also provide the optical motion capture (OMC) system’s raw trajectory marker data in C3D file format and joint angle in CSV file format. This open dataset will provide resources for professionals interested in amputee gait for research in amputee gait detection and tracking algorithms. Moreover, the data will be the control data for comparison in developing advanced prosthetic components.

Engaging vs. Non-Engaging Abutments: An In Vitro Study Evaluating Changes in Microgap and Screw Morphology.

The purpose of this study was to compare the microgap size between engaging (E) and non-engaging (NE) abutments and screw morphology changes between E and NE abutments using scanning electron microscopy (SEM) before and after cyclic loading (CL). Thirty-six implants were arranged into four groups as follows: Group 1, single units with E abutments; Group 2, single units with NE abutments; Group 3, three-unit fixed partial dentures with a hemi-engaging design; and Group 4, three-unit FPDs with two NE abutments. The microgap was evaluated using a stereomicroscope. SEM was used to qualitatively evaluate screw morphology. The specimens were subjected to axial loading first and then lateral loading (30°) using the settings; one million cycles (1.0 × 106 cycles) for each loading axis. There were no significant differences detected in the microgap sizes between the E and NE abutment groups. In addition, there were no significant changes in the microgap sizes after CL in the E or NE abutment specimens. More damage to the screws was noticed after CL compared to before, with no difference in the patterns of damage detected between the E and NE abutments. No significant difference in microgap size was detected between the E and NE abutments. Furthermore, there was no significant difference in microgap size between the different prosthetic designs. From the SEM qualitative evaluation, there were similar screw morphology changes after CL between the E and NE abutments.

Investigation and Finite Element Analysis of The Distal Weight-Bearing Implant

General Background: Osseointegration. a critical advancement in prosthetics, significantly benefits individuals with transfemoral amputations by enhancing their quality of life through innovative implant systems. Specific Background: The study examines a novel distal weight-bearing implant from 17 global systems, featuring a composite nanocoating of hydroxyapatite and silica, evaluated through finite element analysis and mechanical testing. Knowledge Gap: Research on nanocoating's impact on mechanical performance and its integration into advanced prosthetic designs is limited, despite extensive exploration of various implant systems. Aims: The study evaluates the distal weight-bearing implant's effectiveness, focusing on the nanocoating's role in shock absorption and mechanical stability during various gait cycle phases. Results: The design process involved creating a Ti-6Al-4V femoral stem and UHMWPE spacer, with the implant subjected to FEA under gait cycle conditions. Nanocoated samples demonstrated effective shock absorption, though with slightly reduced mechanical properties. The implant’s performance was evaluated for heel strike, midstance, and pre-swing phases, showing adequate load-bearing capacity within safe thresholds. Novelty: This study introduces a detailed analysis of nanocoating impacts on implant performance and integrates biomechanical forces into FEA for enhanced prosthetic design evaluation. Implications: Research indicates nanocoating enhances shock absorption, but further studies are needed to balance mechanical properties with biocompatibility and biological response, potentially improving amputee care outcomes. Highlights: Advanced Implant Design: Transition from transfemoral to knee disarticulation. Nanocoating Impact: Enhances shock absorption; minor mechanical property reduction. FEA Results: Confirms load-bearing capacity through gait cycle phases. Keywords: osseointegration, distal weight-bearing implant, nanocoating, finite element analysis, gait cycle

Human tactile sensing and sensorimotor mechanism: from afferent tactile signals to efferent motor control

In tactile sensing, decoding the journey from afferent tactile signals to efferent motor commands is a significant challenge primarily due to the difficulty in capturing population-level afferent nerve signals during active touch. This study integrates a finite element hand model with a neural dynamic model by using microneurography data to predict neural responses based on contact biomechanics and membrane transduction dynamics. This research focuses specifically on tactile sensation and its direct translation into motor actions. Evaluations of muscle synergy during in -vivo experiments revealed transduction functions linking tactile signals and muscle activation. These functions suggest similar sensorimotor strategies for grasping influenced by object size and weight. The decoded transduction mechanism was validated by restoring human-like sensorimotor performance on a tendon-driven biomimetic hand. This research advances our understanding of translating tactile sensation into motor actions, offering valuable insights into prosthetic design, robotics, and the development of next-generation prosthetics with neuromorphic tactile feedback.

Total Temporomandibular Joint Replacement: Bridging Current Practice With Innovative Horizons For Oral And Maxillofacial Surgeons

Total temporomandibular joint replacement represents a significant advancement in oral and maxillofacial surgery by addressing the complex issues of temporomandibular joint dysfunction and degeneration. This procedure entails the implantation of a joint customized to the patient’s specific requirements, addressing conditions such as benign and malignant lesions, osteoarthritis, and more severe disorders. Available options range from standard commercial prosthetics to custom designs that leverage high-quality graphics and 3D printing for enhanced fit and functionality. Recent innovations have notably advanced temporomandibular joint surgery, with improvements in integration through information matching and shared processes that boost efficiency and longevity. Additionally, the adoption of minimally invasive techniques and robotic assistance has contributed to shorter recovery times, reduced complications, and increased surgical precision. However, challenges persist. Extended implant times, complications, and the need for ongoing patient care remain significant concerns. Long-term follow-up is crucial for evaluating the effectiveness and durability of new prosthetic designs. The field of temporomandibular joint replacement is rapidly evolving, driven by ongoing research and technological advancements aimed at improving patient outcomes, alleviating pain, and enhancing overall health. This review underscores the need for continuous innovation to address the complexities of integration and to advance patient care in the face of evolving surgical demands.

Paediatric Prosthetic Knee Design: The Technical Requirements of a Swing Phase Control Mechanism are Correlated with Parameters of Childhood Growth.

There is a lack of innovation in affordable prosthetic knee joints for children. One significant reason is the absence of technical requirements which consider the foundation of childhood: growth. This study aims to develop and use a modelling tool to determine the technical requirements throughout childhood growth for one prosthetic knee design feature, a swing phase control mechanism (SPCM). 3D gait data of 31 able-bodied children across a range of physical maturities were analyzed. For each participant 2 models were created from a validated paediatric able-bodied musculoskeletal model. The model was first linearly scaled, then a corresponding unilateral right knee-disarticulation amputation model produced by removing segments below the knee and replacing with prosthetic componentry. Long established low-cost prosthetic componentry and a novel polycentric knee were implemented. For each participant, inverse dynamics were conducted and the SPCM torque requirements defined. Prosthetic knee SPCM torque requirements were significantly less than the able-bodied knee to emulate able-bodied gait at free speed: 17.9% (± 10.2) and 66.3% (± 17.0) reduction in maximum extension and flexion torque, respectively. Maximum knee extension torque showed the strongest negative correlation with intact body mass (ρ = -0.6251) whereas flexion torque showed the strongest correlation with height (ρ = 0.6611). Corresponding linear regression fits produced RMSE of 1.91and 1.73 Nm, respectively. Results were also determined for slow and fast speeds. The torque requirements of an affordable paediatric prosthetic knee SPCM are defined and found to strongly correlate with parameters of childhood growth (body mass, height, and age). Current results recommend low-cost paediatric prosthetic SPCM designs can be tailored to accommodate growth. The creation of musculoskeletal models facilitate multiple future studies.

Classification system for maxillary fixed dental prostheses.

To present an addendum to existing fixed dental prostheses (FDPs) classification system for maxillary prostheses. The new classification identifies the relationships between FP-1 (fixed prostheses) designs and newly developed clinical interdental gingival contours. Clinical and laboratory descriptions of the various types of full-arch fixed prostheses are described with photographic illustrations. Benefits and limitations of the various prosthetic designs are explained. Surgical differences in the amount of alveolectomy are illustrated. One clinical case is demonstrated. A new classification system for maxillary implant fixed complete dentures is presented. The new system will serve as an improved communication aid for clinicians, patients, and laboratory technicians. Treatment of patients with edentulous maxillae and/or terminal dentitions and implant fixed complete dentures include several options relative to design and materials. Restorative space can have a major impact on prosthesis design and longevity. Early on in dental implant therapy, prostheses were generally made with cast metal frameworks, denture bases and denture teeth. Prosthetic complications were widely reported. With increased clinical experience and improved materials, computer-aided design and computer-aided manufacturing (CAD-CAM) protocols were developed that allowed stronger prostheses to be constructed in reduced or small restorative volumes. FP-1 ceramic implant-supported fixed prostheses (CISFPs) are designed to replace only the dental hard tissues and to promote preservation and rehabilitation of gingival soft tissues. The physical properties and minimum thickness requirements in full arch prostheses are influenced by several factors including distances between implants and rigid connector sizes. FP-1 CISFPs may be the closest prostheses the profession can offer edentulous patients that mimic the look, feel, and function of missing dentitions. Aesthetic outcomes of FP-1 CISFPs are variable and depend on a multitude of factors. This article presented a classification system that builds on existing classification by identifying the level of papilla heights achieved with FP-1 CISFPs.

Post-hemimaxillectomy rehabilitation as a conservative prosthetic design to enhance functionality: A case report

Post-hemimaxillectomy rehabilitation as a conservative prosthetic design to enhance functionality: A case report

Factors leading to falls in transfemoral prosthesis users: a case series of prosthesis-side stumble recovery responses

BackgroundFalls due to stumbling are prevalent for transfemoral prosthesis users and may lead to increased injury risk. This preliminary case series analyzes the transfemoral prosthesis user stumble recovery response to highlight key deficits in current commercially-available prostheses and proposes potential interventions to improve recovery outcomes.MethodsSix transfemoral prosthesis users were perturbed on their prosthetic limb at least three times while walking on a treadmill using obstacle perturbations in early, mid and late swing. Kinematic data were collected to characterize the response, while fall rate and key kinematic recovery metrics were used to assess the quality of recovery and highlight functional deficits in current commercially-available prostheses.ResultsAcross all participants, 13 (54%) of the 24 trials resulted in a fall (defined as > 50% body-weight support) with all but one participant (83%) falling at least once and two participants (33%) falling every time. In contrast, in a previous study of seven young, unimpaired, non-prosthesis users using the same experimental apparatus, no falls occurred across 190 trials. For the transfemoral prosthesis users, early swing had the highest rate of falling at 64%, followed by mid-swing at 57%, and then late swing at 33%. The trend in falls was mirrored by the kinematic recovery metrics (peak trunk angle, peak trunk angular velocity, forward reach of the perturbed limb, and knee angle at ground contact). In early swing all four metrics were deficient compared to non-prosthesis user controls. In mid swing, all but trunk angular velocity were deficient. In late swing only forward reach was deficient.ConclusionBased on the stumble recovery responses, four potential deficiencies were identified in the response of the knee prostheses: (1) insufficient resistance to stance knee flexion upon ground contact; (2) insufficient swing extension after a perturbation; (3) difficulty initiating swing flexion following a perturbation; and (4) excessive impedance against swing flexion in early swing preventing the potential utilization of the elevating strategy. Each of these issues can potentially be addressed by mechanical or mechatronic changes to prosthetic design to improve quality of recovery and reduce the likelihood a fall.

Concerto of movement: how expertise shapes the synergistic control of upper limb muscles in complex motor tasks with varying tempo and dynamics

Objective. This research aims to reveal how the synergistic control of upper limb muscles adapts to varying requirements in complex motor tasks and how expertise shapes the motor modules. Approach. We study the muscle synergies of a complex, highly skilled and flexible task—piano playing—and characterize expertise-related muscle-synergy control that permits the experts to effortlessly execute the same task at different tempo and force levels. Surface EMGs (28 muscles) were recorded from adult novice (N = 10) and expert (N = 10) pianists as they played scales and arpeggios at different tempo-force combinations. Muscle synergies were factorized from EMGs. Main results. We found that experts were able to cover both tempo and dynamic ranges using similar synergy selections and achieved better performance, while novices altered synergy selections more to adapt to the changing tempi and keystroke intensities compared with experts. Both groups relied on fine-tuning the muscle weights within specific synergies to accomplish the different task styles, while the experts could tune the muscles in a greater number of synergies, especially when changing the tempo, and switch tempo over a wider range. Significance. Our study sheds light on the control mechanism underpinning expertise-related motor flexibility in highly skilled motor tasks that require decade-long training. Our results have implications on musical and sports training, as well as motor prosthetic design.

Design and Analysis of Finger Prosthetics Using Finite Element Methods

According to the Central Statistics Agency (BPS), the total number of physically disabled people in Indonesia until 2020 reached 22.5 million people. However, only around 18% use assistive devices. 3D printing technology in the world of health can be used to print prosthetic materials. However, many previous functional prosthetic designs were still fabricated conventionally and did not pay attention to prosthetic standards and quality. One computational testing method that can be used to test prosthetic strength is the finite element method. The aim of this research is to produce a functional finger prosthetic design that has tested its strength through computational simulations using the finite element method to minimize prosthetic production costs so that the resulting prosthetics are more affordable.The tools needed in this research are a ruler for finger measurements and a computer or laptop with Fusion 360 software.Based on the analysis results, it shows that this model is able to withstand loads of up to 100 N with deformation, stress and safety factor values produced respectively of 0.016 mm, 27,605 MPa and 7.49.

A Study on Materials Used and Longevity of Implant-Supported Prostheses

ABSTRACT Objective: This retrospective research was directed to investigate the longevity and maintenance requirements of implant-supported prostheses in subjects treated at a tertiary care center. Methods: Patient records of individuals who received implant-supported prostheses between January 2018 and December 2020 were retrospectively analyzed. Demographic information, implant type, prosthetic design, and follow-up data were collected. The primary outcomes assessed were prosthetic survival rates and the incidence of complications requiring maintenance interventions. Statistical analysis was performed to identify associations between demographic and clinical variables and the observed outcomes. Results: The research included 150 subjects with an average follow-up duration of 3 years. The overall survival rate of implant-supported prostheses was 90%, with 20% requiring maintenance interventions. Common complications included peri-implantitis (10%), prosthetic fracture (6%), and screw loosening (4%). Significant associations were found between smoking status and peri-implantitis (P < 0.05) and between prosthetic design and prosthetic fracture (P < 0.01). Conclusion: Implant-supported prostheses demonstrated a high overall longevity rate, with a subset of subjects requiring maintenance interventions due to complications. Peri-implantitis, prosthetic fracture, and screw loosening were the most prevalent complications, emphasizing the importance of tailored patient care and risk stratification.

Enhanced Euler–Lagrange Formulation for Analyzing Human Gait With Moving Base Reference

Abstract Euler–Lagrange's formulation is known for its systematic and simplified approach to deriving dynamics of complex systems. In order to apply the existing formulation to human gait dynamics, the base reference frame must be assumed as an inertial reference frame. Conventionally, the ankle joints or the hip joints are regarded as base reference frames during the stance and swing phases of human walking. As these joints are non-inertial in nature during actual locomotion, this assumption could result in inaccurate calculation of lower-limb joint torques and forces. Therefore, in this paper, an existing Euler–Lagrange-based formulation originally developed for fixed-base robotic manipulators is considered and modified to accommodate the movement of the base reference frame with respect to an inertial frame of reference defined outside the human body. The applicability of the modified formulation is studied, implemented, and validated using three standard and publicly available gait datasets covering the phases of walking and running. The joint torques obtained using the proposed dynamic model are compared with reference torques by calculating the mean absolute error values and visually through Bland–Altman plots. The obtained joint torque values and plots indicate a close agreement with published torques, thereby validating the accuracy of the proposed dynamic model. The robust formulation implementation makes it a valuable resource for researchers in this field, offering a reliable framework for gait analysis and the design of lower-limb prosthetics or exoskeletons.

Multi-objective optimization of prosthetic multi-cells foam liner

Restoring mobility using prosthetic limbs anchored in custom sockets is the primary goal of amputee rehabilitation. The contact pressure at the stump-liner interface is critical for improving prosthetic socket design and enhancing amputee satisfaction and comfort. This study aimed to develop and optimize a new customized multicellular foam liner model by identifying the optimal configuration of the liner’s cells to achieve minimal contact pressure between the transtibial limb (stump) and the prosthetic interface while simultaneously minimizing the stump’s immersion in the foam liner. The study employed a multi-objective optimization using the NSGA-II genetic algorithm to optimize the material configurations of the liner cells. The objective function was based on a finite element (FE) model of the customized foam liner, composed of 40 cells, each using one of six foam materials with varying firmness. The optimization process yielded nine different configurations representing the Pareto front. Contact pressure and immersion, represented by displacement in the load direction, were reduced from 140 KPa and 9 mm to 10 KPa and less than 1 mm, respectively. The results obtained in this study motivate future clinical trials on the efficacy of customized multicellular foam liners. These findings provide in-depth insights into prosthesis design and customization, potentially leading to further development in the use of foam rather than silicone for liner manufacturing.