The biological ankle dorsiflexes several degrees during swing to provide adequate clearance between the foot and ground, but conventional energy storage and return (ESR) prosthetic feet remain in their neutral position, increasing the risk of toe scuffs and tripping. We present a new prosthetic ankle intended to reduce fall risk by dorsiflexing the ankle joint during swing, thereby increasing the minimum clearance between the foot and ground. Unlike previous approaches to providing swing dorsiflexion such as powered ankles or hydraulic systems with dissipative yielding in stance, our ankle device features a spring-loaded linkage that adopts a neutral angle during stance, allowing ESR, but adopts a dorsiflexed angle during swing. The ankle unit was designed, fabricated, and assessed in level ground walking trials on a unilateral transtibial prosthesis user to experimentally validate its stance and swing phase behaviors. The assessment consisted of three conditions: the ankle in an operational configuration, the ankle in a locked configuration (unable to dorsiflex), and the subject’s daily use ESR prosthesis. When the ankle was operational, minimum foot clearance (MFC) increased by 13 mm relative to the locked configuration and 15 mm relative to his daily use prosthesis. Stance phase energy return was not significantly impacted in the operational configuration. The increase in MFC provided by the passive dorsiflexing ankle prosthesis may be sufficient to decrease the rate of falls experienced by prosthesis users in the real world.

Individuals with lower limb amputation experience reduced ankle push-off work in the absence of functional muscles spanning the joint, leading to decreased walking performance. Conventional energy storage and return (ESR) prostheses partially compensate by storing mechanical energy during midstance and returning this energy during the terminal stance phase of gait. These prostheses can provide approximately 30% of the push-off work performed by a healthy ankle–foot during walking. Novel prostheses that return more normative levels of mechanical energy may improve walking performance. In this work, we designed a Decoupled ESR (DESR) prosthesis which stores energy usually dissipated at heel-strike and loading response, and returns this energy during terminal stance, thus increasing the mechanical push-off work done by the prosthesis. This decoupling is achieved by switching between two different cam profiles that produce distinct, nonlinear torque–angle mechanics. The cams automatically interchange at key points in the gait cycle via a custom magnetic switching system. Benchtop characterization demonstrated the successful decoupling of energy storage and return. The DESR mechanism was able to capture energy at heel-strike and loading response, and return it later in the gait cycle, but this recycling was not sufficient to overcome mechanical losses. In addition to its potential for recycling energy, the DESR mechanism also enables unique mechanical customizability, such as dorsiflexion during swing phase for toe clearance, or increasing the rate of energy release at push-off.

Objectives: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand. Methods: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e., varying physical demand). Results: The findings revealed both groups of participants (TT LL vs. TF LL) exhibited a similar EEG theta synchrony response as either the cognitive or the physical demand increased. Also, while individuals with TT LL maintained similar performance on the cognitive task during seated and walking conditions, those with TF LL exhibited performance decrements (slower response times) on the cognitive task during the walking in comparison to the seated conditions. Furthermore, those with TF LL neither exhibited regional differences in EEG low-alpha power while walking, nor EEG high-alpha desynchrony as a function of cognitive task difficulty while walking. This lack of alpha modulation coincided with no elevation of theta/alpha ratio power as a function of cognitive task difficulty in the TF LL group. Conclusions: This work suggests that both groups share some common but also different neurocognitive features during dual-task walking. Although all participants were able to recruit neural mechanisms critical for the maintenance of cognitive-motor performance under elevated cognitive or physical demands, the observed differences indicate that walking with a prosthesis, while concurrently performing a cognitive task, imposes additional cognitive demand in individuals with more proximal levels of amputation.

For a real-time robotic prosthetic control, gait event detection plays an important role. In this paper, one novel sensor was proposed to realize gait event detection. The sensor includes one strain gauge bridge, which can reflect the entire deformation of carbon-fiber footplate on a robotic prosthesis. Three unilateral transtibial amputees participated in the experiments. Experimental results show that using the proposed sensor method, gait event detection (stance phase and swing phase) accuracy is approximately 100%. Based on the detected gait events, three locomotion modes (sit, stand, and walk) and the corresponding transition modes could be determined. Difference between different gait event detection systems was further conducted.

Among rare diseases, a fifth of them are associated with oral manifestations. The most frequent are: enamel dysplasia, cleft lip or palate and oligodontia. Beside the pathology, patients are eager of functional therapeutics which often needs prosthodontics. This oral rehabilitation aims to a better life quality.

Teeth absence management in the case of oligodontia necessitates critical analysis of the supporting tissues: the periodontium and the underlying bone. Deciduous teeth with resorbed roots and hypoplasic permanent teeth are often observed. Thus, some questions arise: can we use them as abutments or can we restore them knowing that they present an anomaly in their position and are more fragile? How do we replace many teeth when bone is lacking (clefts, agenesis)? Can we implant on a missing tooth site or can we use autograft? What do we expect for periodontal healing?

Adjacent teeth have often migrated, occlusion is unstable due to mixed dentition and patient’s disease. For example, in mandibular incisors agenesis cases, the remaining deciduous teeth are used when consultation happens at adolescence. This results in upper jaw incisors migration toward mandible and thus an anterior overbite. Orthodontic treatments will allow to recreate gap width and a normal occlusion in order to perform prosthodontics treatment in the best possible conditions. Giving the weak dental and periodontal supports, our attention will be focused on choosing the best option between tooth and implant supported prosthodontics. During the mixed dentition, orthodontic treatment and aesthetic rehabilitation have to be planed at the same time and to last until “definitive” implant and periodontal therapies are possible. In this article, we will present one oligodontia case report to illustrate a possible solution.

This article presents solutions to problems posed by missing teeth in the anterior sector of the arch by synthesizing three groups of parameters, those related to patients, those related to dentists, and those related to the orthodontist.

But the patient, or the parents of patients who are young children, in consultation with the treatment professionals, must make the final decision.

There are many ways dentists can restore teeth prosthetically. Depending on its condition of relative integrity or more serious breakdown and the patient’s loss of other teeth, the practitioner can choose from a variety of quite different procedures ranging from the fabrication of a single ceramo-ceramic crown on a vital tooth to correction of considerable loss of teeth with an implant supported bridge. This paper will evaluate most of these treatment modalities and, in addition to purely prosthetic considerations, will discuss the integration into treatment of periodontal, implant, occlusal, and functional concepts.

There are several clinically useful techniques for delivering radical radiotherapy to the prostate. One such beam arrangement is a conformal four-field box technique. Patients who have undergone a total hip replacement have in place a metallic prosthesis, which presents challenges in achieving a homogenous dose distribution. This is due to the increased density of the metal in comparison to bone and soft tissue. The resultant effect is additional attenuation of the X-ray beam as it passes through the prosthesis. The interaction of the photons with the metal also causes increased scatter. Thus, the dose delivered to the tumour is reduced if it is not corrected for. Due to the uncertainty in the amount of attenuation, it is recommended to avoid irradiating through the hip concerned. This means that the four-field box technique cannot be used. Instead, different field arrangements are used such as three or four oblique fields. This is a retrospective investigation into which field arrangement would be the most appropriate for early stage prostate cancer patients. Ten previously treated prostate patients were planned with different beam arrangements avoiding the prosthesis. The results were analysed and are presented with reference to the doses to the organs at risk and the planning target volume. The results indicate that the beam arrangement of choice should be three fields (anterior, posterior and lateral) or a three-field oblique beam arrangement. It has been proved that these plans are acceptable as a solution in this scenario.

Purpose: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments. Methods: We performed three levels of study. Microscopic examination was made of 64 devices of various sizes, randomly selected from 240 Amplatzer® Septal Occluders that had been exposed to saline solution at 37°C for fourteen months. All samples were studied by electron microscopy ranging from 50 to 5000 times magnification. We also studied microscopically 3 Amplatzer® devices explanted 18–36 months after implantation in dogs, and 2 Amplatzer Septal Occluders removed from patients 18 months (cardiac transplant) and 19 months (died of causes unrelated to device placement) after implantation, which were examined grossly and by electron microscopy up to 5000 times magnification. We then measured the levels of nickel in the blood using inductive plasma mass spectroscopy in 19 patients with implanted Amplatzer® devices, making measurements before and 6 months after implantation. Results: Electron microscopy showed an intact titanium oxide layer with no evidence of corrosion in vitro and in vivo. One explanted device in direct contact with the platinum leads of a pacemaker for eighteen months showed minor pitting of the titanium oxide layer believed to be galvanic in nature. No wire fractures were found in vitro after cycle testing with 400 million cycles, nor in devices taken from the animals and humans. Biochemical studies showed no significant elevation of levels of nickel levels after implantation. Conclusion: Nitinol wire of Amplatzer® septal occlusion devices is resistant to corrosion when exposed to physiologic saline solution, and in experimental animals as well as humans. A device in contact with a platinum pacemaker electrode developed minimal pitting of the titanium oxide layer, believed to be galvanic in nature and of no structural or clinical significance. There is no increase of concentrations of nickel in the blood of patients who have received Amplatzer® nitinol devices. These favorable testing results reveal that nickel-titanium is an inert, corrosion resistant alloy.