Prosthetic Parts Research Articles

Designing and testing lightweight shoulder prostheses with hybrid actuators for movements involved in typical activities of daily living and impact absorption.

Unlike forearm amputees, transhumeral amputees have residual stumps that are too small to provide a sufficient range of operation for their prosthetic parts to perform usual activities of daily living. Furthermore, it is difficult for small residual stumps to provide sufficient impact absorption for safe manipulation in daily living, as intact arms do. Therefore, substitution of upper limb function in transhumeral amputees requires a sufficient range of motion and sufficient viscoelasticity for shoulder prostheses under critical weight and dimension constraints. We propose the use of two different types of actuators, ie, pneumatic elastic actuators (PEAs) and servo motors. PEAs offer high power-to-weight performance and have intrinsic viscoelasticity in comparison with motors or standard industrial pneumatic cylinder actuators. However, the usefulness of PEAs in large working spaces is limited because of their short strokes. Servo motors, in contrast, can be used to achieve large ranges of motion. In this study, the relationship between the force and stroke of PEAs was investigated. The impact absorption of both types of actuators was measured using a single degree-of-freedom prototype to evaluate actuator compliance for safety purposes. Based on the fundamental properties of the actuators identified, a four degree-of-freedom robotic arm is proposed for prosthetic use. The configuration of the actuators and functional parts was designed to achieve a specified range of motion and torque calculated from the results of a simulation of typical movements performed in usual activities of daily living. Our experimental results showed that the requirements for the shoulder prostheses could be satisfied.

Therapeutic cyclic lipopeptides mining from microbes: latest strides and hurdles.

Infectious diseases impose serious public health burdens and often have devastating consequences. The cyclic lipopeptides elaborated by bacteria Bacillus, Paenibacillus, Pseudomonas, Streptomyces, Serratia, Propionibacterium and fungus Fusarium are very crucial in restraining the pathogens. Composed of a peptide and a fatty acyl moiety these amphiphilic metabolites exhibit broad spectrum antimicrobial effects. Among the plethora of cyclic lipopeptides, only selective few have emerged as robust antibiotics. For their functional vigor, polymyxin, daptomycin, surfactin, iturin, fengysin, paenibacterin and pseudofactin have been integrated in mainstream healthcare. Daptomycin has been a significant part of antimicrobial arsenal since the past decade. As the magnitude of drug resistance rises in unprecedented manner, the urgency of prospecting novel cyclic lipopeptides is being perceived. Intense research has revealed the implication of these bioactive compounds stretching beyond antibacterial and antifungal. Anticancer, immunomodulatory, prosthetic parts disinfection and vaccine adjuvancy are some of the validated prospects. This review discusses the emerging applications, mechanisms governing the biological actions, role of genomics in refining structure and function, semi-synthetic analog discovery, novel strain isolation, setbacks etc. Though its beyond the scope of the current topic, for holistic purpose, the role of lipopeptides in bioremediation and crop biotechnology has been briefly outlined. This updated critique is expected to galvanize innovations and diversify therapeutic recruitment of microbial lipopeptides.

Alternative Technologies for Obtaining the Metal-Ceramic Dental Prostheses Imposed by some Clinical Situations – A Case Series

In the contemporary dentistry the highly esthetic prosthetic restorations are readily achievable knowing the patient's expectations, communicating effectively with the dental technician and selecting appropriate materials and technologies. One of the important factors that influence the ceramic resistance in the metal-ceramic restorations is the design of the framework. A design of the framework that provides support for cusps may therefore be advantageous in preventing the fracture of the plating ceramics. The outer geometry of the metal-ceramic restorations is strongly defined by anatomical and physiological circumstances. Although a change in the framework design does not necessarily affect the external form of the restoration, a thicker frame automatically implies a thinner layer of veneering and vice versa.In this study we present a series of clinical cases in which we have used different techniques for modeling the wax patterns of the future metal structure according to several clinical features. There are presented techniques for obtaining the layouts for the metallic structures of partial or total esthetic metal-ceramic restorations, dental supported or implant supported, classic techniques and innovative techniques that allow previewing the final aspect of restoration and the transfer of clinical data for a highly functional prosthesis.The wax patterns are exact copies of future prosthetic parts, so should be done with great care. The ergonomics had made place also at this level currently existing a multitude of techniques and materials that facilitate the dental technician’s work.

Application of a modified healing cap in implant supported auricular prosthesis: case report

Auricular prosthesis are fabricated generally in congenital deformities or tissue deficiencies gained by a trauma. Due to the difficulty of prosthetic localization, implant supported auricular prosthesis have important mechanical advantages when compared to those used with tissue adhesives. However, during the prosthetic preparation period of post implantation stage, problems like thickening of the skin tissue around the healing caps may be seen. This condition often requires a third surgical procedure for remodification of the healing tissues. This case report presents the application of modified healing cap which was attached to the prosthetic part of the patient which could not be rehabiliated due to the thickening of the tissue .

Considerations on the Selection of Materials for Prosthetic Parts Obtained by Incremental Forming

Abstract Incremental forming is a novel but promising procedure for the flexible manufacturing of parts starting from metal sheets. It could be very useful in the medical area and especially in orthopedic prosthetics, where each part needs to be very precisely made, but at the same time has to have a unique shape. In this context, the selection of the material that could best satisfy the manufacturing and usage requirements is very important. The current paper suggests a unified parameter that could be used for assessing the suitability of a specific material for the manufacturing, by incremental forming, of prosthetic parts that would be used in human surgery

Researches Regarding the Usage of Titanium Alloys in Cranial Implants

In the last few decades, the concept of flexible manufacturing has started to gain more and more attention, as an adaptation of production methods to the increasingly varied demands by customers. Therefore, new procedures have been introduced as alternatives to the classical ones, a very promising one being incremental forming [. A possible application for this new procedure, targeted by the authors of this paper, is the manufacturing of custom-shaped prosthetic parts for use in various areas of human medicine. Such prostheses can have a functional role, when they target the replacing of a functional component of the human body, or an esthetic role, when they target the solving of problems related to the appearance of the human body. Among all titanium and its alloys, the mainly used materials in biomedical field are the commercially pure titanium (cp Ti, grade 2) and Ti6Al4V (grade 5) alloy [.

Outcomes of complex femorodistal sequential autologous vein and biologic prosthesis composite bypass grafts

Femorodistal autologous vein bypass proves to be the preferred surgical therapy for long arterial occlusions and provides excellent early and long-term results in critical lower limb ischemia. Whenever vein length was insufficient and two distal outflow arteries were present, a sequential composite bypass configuration was chosen with human umbilical vein (HUV) or ovine collagen prosthesis (Omniflow II; Bio Nova International Pty Ltd, North Melbourne, Australia) as the proximal prosthetic part of the bypass. Single-center experience with this technique regarding limb salvage, graft function, secondary reinterventions, and biodegeneration is presented. Between January 1998 and January 2009, 122 consecutive sequential composite bypass operations were performed on 116 patients for short-distance claudication (2), chronic critical ischemia (117), or acute ischemia (3) in the absence of sufficient autologous vein length. HUV was used in 90 cases and Omniflow II in 32 cases. Grafts were followed by duplex scan supplemented by angiography in case of recurrent ischemia with prospective documentation of follow-up data in a computerized vascular database. Retrospective analysis of graft patency, limb salvage, and aneurysmal degeneration of the biologic prosthesis was performed. Mean follow-up was 59 ± 45.5 months (range, 1-161 months). The 30-day mortality was 4.1%. Early postoperative complete or partial bypass thrombosis developed in 16% (20 cases) and required successful revision in 16 cases. During follow-up, 30 complete and 12 partial bypass occlusions occurred, necessitating selective surgical or interventional revision. Primary, primary assisted, and secondary patency rates and the limb salvage rate were 48%, 62%, 71%, and 87%, respectively, after 5 years and 26%, 46%, 54%, and 77%, respectively, after 10 years for all bypasses. Late biodegeneration of HUV prostheses was detected in four instances. Late graft patency and limb salvage were good. These factors, combined with a tolerable rate of late aneurysmal degeneration, justify the use of biologic vascular conduits and autologous vein for complex femorodistal reconstructions.

Method for Manufacturing Custom-Shaped Prosthetic Parts from Titanium Alloys by Incremental Forming Using Industrial Robots

The last decade has shown an increasing interest in a new class of forming processes known as Incremental Sheet forming (ISF). A possible application for this new procedure, targeted by the authors of this paper, is the manufacturing of custom-shaped prosthetic parts for use in various areas of human medicine. Such prostheses can have a functional role, when they target the replacing of a functional component of the human body, or an esthetic role, when they target the solving of problems related to the appearance of the human body. In this paper the authors aim to determine the strain hardening curves for the titanium alloy Ti6Al4V at room temperature and at 800°C. The incremental forming process will be performed by means of an industrial robot.

Adjunctive Orthodontic Applications in Dental Implantology

Implant placement is often necessitated for replacement of teeth with pathologically damaged alveolar bone due to periodontitis or traumatic injury. Surgical augmentation of resorbed bone has many limitations, including lower efficacy of vertical augmentation than horizontal augmentation, as well as morbidity associated with grafting procedure. Orthodontic therapy has been proposed as a useful method for augmenting the resorbed alveolar bone and reforming aesthetically appealing gingival margin, prior to implant placement. This narrative review summarizes the available evidence for the application of orthodontic strategies that can be used as adjunct in selected cases to augment bone volume for the future implant site and maintain space for the prosthetic parts of the implant. These are (1) orthodontic extrusion of compromised teeth to generate vertical bone volume and enhance gingival architecture, (2) tooth preservation and postponing orthodontic space opening to maintain bone volume in future implant site, (3) orthodontic implant site switching to eliminate the deficient bone volume or risky implant sites, and (4) the provision of a rigid fixed-bonded retainer to maintain the implant site. Although there are no randomized controlled clinical trials to evaluate the efficacy of orthodontic therapy for implant site development, clinical case reports and experience document the efficacy of orthodontic therapy for this application.

Neutrale zone. Een bij vervaardiging van volledige gebitsprothesen vaak verwaarloosde anatomische ruimte

When designing complete dentures, consideration should not only be given to the occlusal concept but also to the occlusal system as a whole. An important part of that system is the position of the artificial teeth. This prosthetic part of the occlusal system is directly related to the tongue, the floor of the mouth, the cheeks and the lips. The artificial teeth of the mandibular dentures have to be positioned in the so-called 'neutral zone' of the edentulous mandible. The neutral zone is the stress-free area between the tongue on one side and, on the other side, the mimic muscles, which are responsible for the movement of the lips and cheeks. Moreover, the maxillary posterior artificial teeth and the supporting acrylic surfaces of the maxillary denture have an important function in providing support for the upper lip and cheeks in order to prevent a 'denture look' appearance.

Sustainability of additive manufacturing: measuring the energy consumption of the laser sintering process

The term additive manufacturing (AM) describes a collection of production techniques enabling the layer-by-layer manufacture of components using digital data and raw material as inputs. The AM technology variant most frequently used in the production of end use parts is laser sintering (LS). It has been suggested that efficient usage of the energy inputs is one of the advantages of the technology. This paper presents a comparative assessment of the electricity consumptions of two major polymeric LS platforms: the Sinterstation HiQ + HS from 3D Systems and the EOSINT P 390 from EOS GmbH. The energy inputs to a build consisting of two prosthetic parts were recorded during power-monitoring experiments conducted on both platforms. This paper injects clarity into the ongoing research on the AM energy consumption by applying a novel classification system; it is argued that the AM energy usage can be divided into the job-dependent, time-dependent, geometry-dependent, and Z-height-dependent energy consumption values. The recorded mean real power consumption conforms to the values that have been reported for similar platforms. The measured energy consumption rates are higher than reported elsewhere. It is also shown that the purely time-dependent energy consumption is the main energy drain. Furthermore, the presentation of results in the context of previous literature highlights the caveats attached to summary metrics of the AM input usage.

Testing and evaluation of prosthetic parts and orthotic parts

Testing and evaluation of prosthetic parts and orthotic parts

Promontofijación laparoscópica. Nuestra técnica

Objectives The pathology of the pelvic flool, including the urinary incontinence, the anal incontinence and the genital prolapse, is very dominant, concerning approximately a third of the adult women. It is fundamental that this musculature supports a good function, because of the weakness of the pelvic floor produces urinary incontinence, cysto and rectocele, genital prolapses and sexual dysfunctions. The above mentioned pathology can be corrected by laparoscopic promontofixation, whatever the previous history of pelvic surgery, including the placing of prosthetic material. In this article we describe the above mentioned intervention. Material and methods Preoperative care is standardized and is accompanied by antibiotic prophylaxis, preventive antithrombotic treatment and in the event of a history of pelvic surgery, a digestive preparation. Positioning of the patient must plan a 30° Trendelenbourg position. After the introduction the trocars, initial surgery comprises anterior dissection of promontory after incision of the posterior peritoneum with the patient placed beforehand in a Trendelembourg position. After that, we make interrectovaginal dissection to free the whole posterior surface of the vagina. This is followed by the installation of a posterior mesh pre-cut in an arc. After intervesical vaginal dissection, the anterior prosthesis comprising a precut polyester mesh is fixed avoiding excess traction. The end of the surgery involves careful reperitonization of all the prosthetic parts. Possible specific surgical complications are vascular and visceral wounds. Results y conclusions The technique allows the correction of the dysfunction of the pelvic floor and incontinence with good anatomical and functional results. Postoperative secondary haemorrhage and gastrointestinal occlusion may ocurr. Occurrence of an inflammatory syndrome and low back pain suggests spondylodicitis and MRI should be performed. Vaginal erosion on the prosthesis may occur after several months and seems relatively independent of the prosthetic material used.

Can High-Flexion Tibial Inserts Improve Range of Motion After Posterior Cruciate-Retaining Total Knee Arthroplasty?

Interest in high-flexion total knee arthroplasty (TKA) prostheses designed to provide better postoperative range of motion (ROM) is widespread. We sought to determine whether changes in surface geometry of the tibial polyethylene insert could improve postoperative ROM in a consecutive series of patients undergoing TKA with retention of the posterior cruciate ligament (PCL). Two cohorts with Smith & Nephew (Memphis, Tennessee) Posterior Cruciate-Retaining Genesis II total knee prostheses were compared, 79 knees (65 patients) using standard tibial inserts and 85 knees (72 patients) using high-flexion inserts. The standard insert has a slightly raised posterior lip, whereas the high-flexion insert is recessed downward at the posterior margin to facilitate femoral rollback in flexion and eliminate impingement of the femoral component on the back of the polyethylene during rollback. Mean ROM 1 year postoperatively was 112.0° in patients receiving the standard insert and 119.3° in patients receiving the high-flexion insert. Preoperative ROM was similar in both groups. Flexion improvement in the high-flexion group over the standard insert group was statistically significant (P<.001). Final Knee Society Scores did not differ amongst patients receiving the standard and high-flexion inserts. Our study demonstrates that improved postoperative flexion can be achieved without changing surgical technique, bony cuts, or metallic prosthetic parts. This is the first report that we are aware of that documents improvement in ROM after PCL-retaining TKA through the use of high-flexion inserts.

Twenty-first century challenges for biomaterials

During the 1960s and 1970s, a first generation of materials was specially developed for use inside the human body. These developments became the basis for the field of biomaterials. The devices made from biomaterials are called prostheses. Professor Bill Bonfield was one of the first to recognize the importance of understanding the mechanical properties of tissues, especially bone, in order to achieve reliable skeletal prostheses. His research was one of the pioneering efforts to understand the interaction of biomaterials with living tissues. The goal of all early biomaterials was to 'achieve a suitable combination of physical properties to match those of the replaced tissue with a minimal toxic response in the host'. By 1980, there were more than 50 implanted prostheses in clinical use made from 40 different materials. At that time, more than three million prosthetic parts were being implanted in patients worldwide each year. A common feature of most of the 40 materials was biological 'inertness'. Almost all materials used in the body were single-phase materials. Most implant materials were adaptations of already existing commercial materials with higher levels of purity to eliminate release of toxic by-products and minimize corrosion. This article is a tribute to Bill Bonfield's pioneering efforts in the field of bone biomechanics, biomaterials and interdisciplinary research. It is also a brief summary of the evolution of bioactive materials and the opportunities for tailoring the composition, texture and surface chemistry of them to meet five important challenges for the twenty-first century.

Laparoscopic promontofixation. Our technique

ObjectivesThe pathology of the pelvic floor, including urinary incontinence, anal incontinence and genital prolapse, is very dominant, concerning approximately a third of adult women. It is fundamental that this musculature supports a good function, because weakness of the pelvic floor produces urinary incontinence, cysto and rectocele, genital prolapses and sexual dysfunctions. The abovementioned pathology can be corrected by laparoscopic promontofixation, whatever the previous history of pelvic surgery, including the placing of prosthetic material. In this article we describe the abovementioned intervention. Material and methodsPreoperative care is standardized and is accompanied by antibiotic prophylaxis, preventive antithrombotic treatment and in the event of a history of pelvic surgery, a digestive preparation. Positioning of the patient must plan a 30° Trendelenbourg position. After the introduction of the trocars, initial surgery comprises anterior dissection of promontory after incision of the posterior peritoneum with the patient placed beforehand in a Trendelembourg position. After that, we make interrectovaginal dissection to free the whole posterior surface of the vagina. This is followed by the installation of a posterior mesh pre-cut in an arc. After intervesical vaginal dissection, the anterior prosthesis comprising a precut polyester mesh is fixed avoiding excess traction. The end of the surgery involves careful reperitonization of all the prosthetic parts. Possible specific surgical complications are vascular and visceral wounds. Results and conclusionsThe technique allows the correction of the dysfunction of the pelvic floor and incontinence with good anatomical and functional results. Postoperative secondary haemorrhage and gastrointestinal occlusion may occur. Occurrence of an inflammatory syndrome and low back pain suggests spondylodicitis and MRI should be performed. Vaginal erosion on the prosthesis may occur after several months and seems relatively independent of the prosthetic material used.

Simulation of a parallel mechanical elbow with 3 DOF

The kinematics simulation and modeling of a mechanical elbow of 3 degrees of freedom, is introduced by highlighting the main features of the mechanism related to the design criteria. The mechanical elbow is used as a transhumeral prosthetic part, and it has been built as a parallel topology consisting of electric linear actuators and universal joints. The parallel mechanism has 4 legs. 3 are electric linear actuators, and the fourth leg provides mechanical support for the whole structure and holds a DC Motor that performs the action of gripping objects. Furthermore, this paper shows the inverse kinematics for the elbow by geometric methods, and the MatLab‐simulation results show the workspace of the movement and the ability of the mechanical elbow to replicate the movements of a biological one.

Criteria for selection of Implant cases

Aims: To evaluate upper and lower limits of the parameters used such as (age, sex, or selection of patient), and to detect the grade of understanding and acceptance of Iraqi publics for the implant surgery (education level). Materials and Methods: From a total of 300 patients seeking implant therapy in Al–Salam Hospital Implantology Center, only 45 patients were chosen to undergo implant surgery with age group 17– >60 years during the period from February 2002 to February 2005. A case sheet was specially prepared for this study containing information needed to determine the suitable criteria of implantation. Frialit–2 implant system was used with its different lengths and widths (color– coded). Maxillary and mandibular impressions, registration of maxillo–mandibular jaw relation records were done for each patient to record all findings. Data were collected and statically analyzed. Results: The higher age group patients were 17–30 years with percentage 5.33%, while non–operated patients 51–60 years showed high percentage of 29.66%. Criteria of the forty five patients (22 females and 23 males) participated in this study were statistically analyzed concerning the economical level. The operated patients showed 57.77% level I (high), 40% level II (moderate) and 2.22% level III (low). While for education level showed 53.3% level I, 42.2% level II and 4.4% level III. Conclusion: Low percentage of educational level of patients need an explanation about surgical and prosthetic parts of dental implant to elevate the education level of patients. In addition to educational level, economical level of patient plays an important role in the criteria for selection of patients.

Registration completeness in the Norwegian Arthroplasty Register

Introduction A high degree of registration completeness is necessary in order to obtain unbiased and accurate register-based study results. We investigated the completeness of registration in the national Norwegian Arthroplasty Register (NAR).Material and methods Registration completeness for the years 1999–2002 was calculated as a percentage, with the number of joint replacements reported to the NAR as numerator and those reported to the Norwegian Patient Register (NPR) as denominator. While the NAR received information directly from the orthopedic surgeons on a voluntary basis, the NPR, which is mandatory, received information from the electronic administrative patient records of the hospitals.Results Registration completeness in the NAR was 97% (97% for primary operations; 101% for revisions). Completeness was 98% (97%; 106%) for hip replacements, and for knee replacements it was 99% (99%; 97%). Hip and knee replacements represented 95% of all operations. However, completeness was poorer for less common joint replacements and poorest for ankle implants (82%; 40%) and wrist implants (52%; 14%). In the NAR, completeness of registration of revisions involving only removal of one or more prosthetic parts was lower than for exchange revisions for all types of joint replacement. For hip implants, 76% of the removal revisions (80% of Girdlestone procedures) were reported, and for knee implants the figure was 62%. According to NPR statistics, removal procedures accounted for 9% of all revisions of hip and knee replacements.Interpretation In the NAR, registration completeness of hip and knee replacements was high both for primary operations and exchange revisions. For some of the less common joint replacements, completeness was low and may—if not improved—compromise prosthesis survival studies. The lower registration completeness of removal revisions also needs to be improved. ▪

Remote access to CAD databases using an information sharing system

This paper describes the access to a database of prosthetic parts using an information sharing system (ISS). The prosthetic parts modeled are made of ceramic materials. The prosthetic parts modeled are a formal head, a cup, and a cup and head device. The information about the prosthetic parts is based on a feature based model and is stored in a relational database which is a part of a CAD system. The model for the information sharing system is object-oriented. The relational database is accessed remotely from the object-oriented model of the ISS using a gateway to the CAD system. This implementation illustrates two key concepts: the ISS approach to distributed, heterogeneous database integration and the ISS methodology for building gateways. It also shows some of the problems and solutions in databases that do not support sql type queries.