Design for Multi-Dimensional Stages of Lymphoedema Self-Management

This study investigates the experience of people with the chronic medical condition lymphoedema, to inform the design of new products. Articles from literature that describe lived lymphoedema experiences are thematically synthesised from a behavioural lens. People with lymphoedema go through stages toward achieving levels of expertise, motivation and routine, to maintain effective self-management in the long-term. A preliminary framework is proposed that presents four themes (competence, autonomy, daily routine and socio-psychological) and their stages. The purpose of the framework is to assist designers in understanding how people with lymphoedema experience self-management. Focusing on facilitating a transition through these multi-dimensional stages is suggested as a means to aid the design of supportive health products. Related design implementations are discussed through product examples. This framework is developed as part of a wider research project, where the following stages will be concerned with refinement of the framework through primary research with people with lymphoedema and their healthcare providers

3D Computer Modeling Analysis of the Surface Area and Thread Volume of the Common Sliding Hip Screw

Introduction: The Sliding Hip Screw (SHS) is a tried and tested method used to treat intertrochanteric hip fractures. Lag screw cut-out is a major complication of SHS fixation and accepted risk factors are often re-evaluated. We aim to demonstrate a new hypothesis of cut-out using 3D reconstructive modelling. We propose that the risk of cut-out is much greater in lag screws with a smaller thread surface area and larger thread volume. Method: The four commonly used SHS lag screw systems (Biomet, Synthes, Stryker and Smith & Nephew) were CT scanned and the images processed and turned into 3D computer models for further analysis. Results: There were significan differences between the surface area and thread volumes of the lag screws between manufacturers ranging from 67.0mm2 - 347.4 mm2 and 166.376mm3 - 225.687mm3 respectively. Discussion: Assuming the consistency of bone is equal, we propose that the risk of cut-out is much greater in lag screws with a smaller surface area to thread volume ratio (SA:TV). The reamer design of lag screws is also discussed. Conclusion: Although there are many non-modifiable risk factors that contribute to screw cut-out, selecting the right raw materials for SHS fixation will have a favorable impact on the overall risk

Comparison of virtual and physical dimensions in AM resin dental devices and fit of devices with conventionally produced base plates

Purpose – The purpose of this study is to develop and apply clinically relevant methods of analysing the accuracy of dental appliances fabricated using additive manufacture (AM) compared to the computer-aided design (CAD) geometry. The study also comparedfit between conventionallylaboratory-fabricated and AM-produced base plates. Design/methodology/approach – The techniques were applied to two types of dental devices where AM fabrication methods could foreseeably be used as an alternative to laboratory production. “L” and cubic shapes of defined dimensions and spatial locations were positioned on the devices which were fabricated using AM. For assessing the dimensions, the“L”and cubic shapes were then measured on the physical builds ten times andcompared to the CAD model. To assess thefit of AM and lab-produced devices, three upper and three lower conventionally fabricated acrylic baseplates were compared to three upper and three lower plates. Silicone impression material was allowed to set between the casts and the base plateswhichfilled any discrepancy between the two surfaces. The thickness of this silicone media was measured ten times atfive different points on eachbase plate type and the results compared. Findings –The results indicated that the evaluated CAD/AM technique is able to produce dental appliance components that are consistent with tolerance levels that would be expected with conventional methods of base plate design. This research demonstrated that a fully CAD/AM methodology represents a potentially viable alternative to conventional lab-based methods for two types of dental appliances

The computer-aided design and rapid prototyping fabrication of removable partial denture frameworks

This study explores the application of computer-aided design and manufacture (CAD/CAM) to the process of electronically surveying a scanned dental cast as a prior stage to producing a sacrificial pattern for a removable partial denture (RPD) metal alloy framework. These are designed to retain artificial replacement teeth in the oral cavity. A cast produced from an impression of a patient's mouth was digitally scanned and the data converted to a three-dimensional computer file that could be read by the computer-aided design (CAD) software. Analysis and preparation were carried out in the digital environment according to established dental principles. The CAD software was then used to design the framework and generate a standard triangulation language (STL) file in preparation for its manufacture using rapid prototyping (RP) methods. Several RP methods were subsequently used to produce sacrificial patterns, which were then cast in a chromium-cobalt alloy using conventional methods and assessed for accuracy of fit. This work demonstrates that CAD/CAM techniques can be used for electronic dental cast analysis, preparation, and design of RPD frameworks. It also demonstrates that RP-produced patterns may be successfully cast using conventional methods and that the resulting frameworks can provide a satisfactory fit

Additively manufactured versus conventionally pressed cranioplasty implants: An accuracy comparison

This article compared the accuracy of producing patient-specific cranioplasty implants using four different approaches. Benchmark geometry was designed to represent a cranium and a defect added simulating a craniectomy. An ‘ideal’ contour reconstruction was calculated and compared against reconstructions resulting from the four approaches –‘conventional’, ‘semi-digital’, ‘digital – non-automated’ and ‘digital – semi-automated’. The ‘conventional’ approach relied on hand carving a reconstruction, turning this into a press tool, and pressing titanium sheet. This approach is common in the UK National Health Service. The ‘semi-digital’ approach removed the hand-carving element. Both of the ‘digital’ approaches utilised additive manufacturing to produce the end-use implant. The geometries were designed using a non-specialised computer-aided design software and a semi-automated cranioplasty implant-specific computer-aided design software. It was found that all plates were clinically acceptable and that the digitally designed and additive manufacturing plates were as accurate as the conventional implants. There were no significant differences between the additive manufacturing plates designed using non-specialised computer-aided design software and those designed using the semi-automated tool. The semi-automated software and additive manufacturing production process were capable of producing cranioplasty implants of similar accuracy to multi-purpose software and additive manufacturing, and both were more accurate than handmade implants. The difference was not of clinical significance, demonstrating that the accuracy of additive manufacturing cranioplasty implants meets current best practice

A pilot study in the application of texture relief for digitally designed facial prostheses

This pilot research aims to identify and assess suitable technologies that may be used to capture, create, and produce fine textures and wrinkles that may be incorporated into computer aided prosthesis design and production techniques. A range of suitable technologies is identified and two methods that may be used in different prosthetic rehabilitation situations are assessed: the creation of three-dimensional relief in a computer aided design environment and the capture of facial anatomy and texture using fringe-projection surface scanning. Patterns were produced using the suitable rapid prototyping processes identified, and these were assessed by a qualified and experienced prosthetist. The suitability of the technologies is commented upon, limitations discussed, and future directions identified

Computer-aided methods for single stage fibrous dysplasia excision and reconstruction in the zygomatico-orbital complex

Computer Aided Design and Additive Manufacture (CAD/AM) technologies are sufficiently refined and meet the necessary regulatory requirements for routine incorporation into the medical field, with long-standing application in surgeries of the maxillofacial and craniofacial region. They have resulted in better medical care for patients, and faster, more accurate procedures. Despite ever-growing evidence about the advantages of computer aided planning, CAD and AM in surgery, detailed reporting on critical design decisions that enable methodological replication, and the development and establishment of guidelines to ensure safety, are limited. This paper presents a novel application of CAD and AM to a single stage resection and reconstruction of fibrous dysplasia in the zygoma and orbit. It is reported in sufficient fidelity to permit methods replication and design guideline developments in future cases, wherever they occur in the world. The collaborative approach included engineers, designers, surgeons and prosthetists to design patient-specific cutting guides and a custom implant. An iterative design process was used, until the desired shape and function were achieved, for both of the devices. The surgery followed the CAD plan precisely and without problems. Immediate post-operative subjective clinical judgements were of an excellent result. At 19 months post-op, a CT scan was undertaken to verify the clinical and technical outcomes. Dimensional analysis showed maximum deviation of 4.73 mm from the plan to the result, while CAD-Inspection showed that the deviations range between -0.1 and -0.8 mm, and that the majority of deviations are located around the –0.3 mm. Improvements are suggested and conclusions drawn regarding the design decisions considered critical to a successful outcome for this type of procedure in the future

Trial fitting of a removable partial denture framework made using computer-aided design and rapid prototyping techniques

Previous studies of CAD/CAM-produced sacrificial patterns for removable partial denture frameworks have been documented but to date, no such restorations have been test-fitted to a patient. This paper provides details of the first trial fitting to a patient of an RPD framework, the sacrificial pattern of which was produced by CAD/CAM and RP technologies. A cast of the patient was scanned and the normal procedures of dental surveying and pattern build were undertaken with reference to the scanned model using computer-aided design. A sacrificial pattern of the design was produced by rapid prototyping technology. After spruing the pattern, investment-casting and finishing techniques were carried out according to conventional principles. The framework was successfully trial-fitted to the patient and clinically judged to be acceptable for the next stage of denture fabrication, that of adding acrylic bases and artificial teeth

Klinička evaluacija inlej-retiniranih adhezivnih mostova tokom dvogodišnjeg opservacionog perioda

Introduction. Inlay retained adhesive restorations present a conservative approach when a single tooth is missing in the posterior region. Material and methods. Twenty five restorations were included in the clinical study. Patient selection, preparation technique as well as denture fabrication followed current principles in this area. Patients were examined every 6 months over a 2 year examination period. Results were statistically analyzed. Results. The success rate for the first year comes to 91.1%, while cumulative success probability during the second year (24 months) was 86.6%. Furthermore, colour, texture and marginal staining were satisfactory during the observation period. Conclusion. Fibre-reinforced composite adhesive dentures are a tooth preserving, minimally invasive, aesthetic and reliable treatment option for single tooth replacement in the posterior area.Uvod. Inlej retinirani adhezivni mostovi predstavljaju konzervativni modalitet tretmana nedostatka pojedinačnog zuba u bočnoj regiji. Materijal i metod. U kliničku studiju, uključeno je 25 adhezivnih nadoknada. Odabir pacijenata, principi preparacije, kao i tehnika izrade mostova urađeni su prema važećim standardima u ovoj oblasti. Pacijenti su praćeni na svakih 6 meseci tokom dvogodišnjeg perioda. Rezultati su statistički obrađeni. Rezultati. Uspešnost nadoknada u prvoj godini iznosi 91.1%, dok kumulativna uspešnost tokom druge godine (24 meseca) iznosi 86.6%. Takođe, ocena boje, teksture i marginalnog prebojavanja daje zadovoljavajuće rezulate tokom perioda praćenja. Zaključak. Kompozitne nadoknade ojačane vlaknima su minimalno invazivni, estetski i pouzdan način tretmana minimalne krezubosti bočnog segmenta denticije

Utvrđivanje korozionih karakteristika stomatološke legure sa induktivno spregnutim plazma masenim spektrometrom

Corrosion resistance is one of the characteristics that dental alloy should possess as it should be placed in the oral cavity. Adverse tissue reactions of the gingiva and the periodontium close to dental cast alloys may be caused by the effects of released metal elements. Corrosion effect of dental Co-Cr-Mo alloy was investigated by ICP MS according to the EN ISO 10271 and EN ISO 22674. Co- Cr dental alloy Remanium GM 800+ (Dentaurum Ispringen, Germany was tested in artificial saliva for 7 days at 37ºC. The released metals were detected by Nexion 300X ICP MS (Perkin Elmer, USA). The results showed that the metal release was very low for Co, Cr and Mo, far below the permitted levels. ICP-MS can be considered as very reliable method for such a research.Otpornost na koroziju je jedna od karakteristika koju poseduju stomatološke legure koje trebaju biti postavljene u usnoj duplji. Neželjene reakcije tkiva gingive i parodoncijuma sa stomatološkim legurama može biti uzrokovano efektima oslobođenih metalnih elemenata. Efekat korozije stomatološke Co- Cr -Mo legure ispitana je ICP MS prema EN ISO 10271 i EN ISO 22674 . Co- Cr stomatološke legure Remanium GM 800 + ( Dentaurum Ispringen , testirano u Nemačkoj u veštačkoj pljuvački tokom 7 dana na 37º C. Otkriveni su oslobođeni metali Nekion 300Ks ICP MS ( Perkin Elmer , SAD ). Rezultati su pokazali veoma slabo oslobađanje metala, Cr i Mo , daleko ispod dozvoljenih nivoa. ICP -MS može smatrati veoma pouzdan metod za ovakvo istraživanje