Robert Williams

Rapid manufacture of removable partial denture frameworks

Purpose – The aim of this study was to explore the application of rapid manufacturing (RM) to the production of patient specific, custom‐fitting removable partial denture (RPD) alloy frameworks. RPDs are metal frameworks designed to retain artificial replacement teeth in the oral cavity.Design/methodology/approach – The study was undertaken by applied case study. An RPD was designed using computer‐aided design software according to well‐established dental technology design principles, based on a digitally scanned cast produced from an impression of the patients mouth. The RPD design was then exported as an STL file in preparation for direct manufacture using selective laser melting. Dimensionally accurate frameworks were manufactured in 316L stainless steel and chromium‐cobalt alloy. These were assessed for accuracy of fit and function on the patient cast and on the patient in clinic.Findings – This successful case study demonstrates that an RM approach can produce fully functional, precisely fitting RPD...

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

Abstract 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 patients 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.

Social Aspects of the Impact of Information and Communication Technologies on Agri-Food SMEs in Wales

Small and medium-sized enterprises (SMEs) need to adapt and change to remain competitive in the rapidly changing business environment of the twenty-first century. As with many other industries this is evident in the agri-food industry in Wales, where agri-food SMEs can obtain a competitive advantage through the use of information and communication technologies (ICT), especially the Internet and Websites. It is argued that many of these firms are often inadept at implementing changes that are technology-enabled. Policy makers, including the Welsh Agri-Food Partnership, also recognize that the agri-food culture is adversarial in nature and this needs to be addressed if technical advancement is to be achieved. With the recognition of the importance of e-business in other industries, there is a danger that many agri-food SMEs will be technology-disabled. The aim of this paper, therefore, is to explore the social consequences of the slow adoption of the Internet and Websites by agri-food SMEs in Wales and to consider ways of overcoming this problem. The paper concludes by reporting on ICT assistance provided by support schemes in Wales and on the social, political and cultural implications for farming communities.

Use of the Internet and SME Characteristics to Expand Scale and Geographic Scope of Sales: The Case of the United Kingdom

The potential of the Internet to both geographically expand customer bases and provide a source of sales growth has led to a rapid embracement of the Internet by a majority of small businesses in the United Kingdom. However, many studies suggest that much of this adoption takes the form of simple Web sites representing little more than an electronic brochure. Although theories and models have been proposed suggesting adoption and development of e-commerce takes a staged process, with firms moving to more complex e-commerce processes after first mastering simpler forms of Web site, studies have found mixed evidence with regard to this. This paper investigates the level of Small and Medium Enterprise (SME) Web site adoption and functionality and how this relates to growth aspirations, specifically the geographical expansion of customer bases. One potential explanation for this slow uptake of true e-commerce is a lack of employees with basic and advanced IT skills. The possibility that Information Technology (IT) skills shortages could explain the gap between the Internet’s potential and the extent of involvement by a vast majority of UK SMEs is explored. Discussion within the paper is complemented with analysis of data from a large survey of SMEs.

Small Business Sales Growth and Internationalization Links to Web Site Functions in the United Kingdom

The potential of the Internet to both geographically expand customer bases and provide a source of growth has led to a rapid embracement of the Internet by a majority of small businesses in the United Kingdom. However, many studies suggest that much of this adoption takes the form of simple websites representing little more than an electronic brochure. This paper investigates the level of Small and Medium Enterprise (SME) website adoption and functionality and how this relates to growth aspirations, specifically the geographical expansion of customer bases. The possibility that IT skills shortages could explain the gap between the Internet’s potential and the extent of involvement by a vast majority of UK SMEs is explored.

Comparative analysis of structure and hardness of cast and direct metal laser sintering produced Co-Cr alloys used for dental devices

Purpose – The purpose of this paper is to analyse structure and measure hardness of Co-Cr dental alloy samples made with two different technologies, conventional casting method (CCM samples) and additive direct metal laser sintering technology (DMLS samples), and to compare the results. Design/methodology/approach – CCM samples were made in a conventional casting machine, using remanium 800+ Co-Cr dental alloy (Dentaurum, Ispringen, Germany). DMLS samples were fabricated out of EOS CC SP2 Co-Cr alloy (EOS, GmbH, Munich, Germany) using DMLS technology. Samples for structural analysis were plate-shaped (10 × 10 × 1.5 mm3) and for the hardness test were prismatic-shaped (55 × 10.2 × 11.2 mm3). Structure was analysed via an inverting microscope and colour metallography method. Findings – CCM samples have a dense, irregular dendritic mesh, which is typical for the metallic phase of the Co-Cr dental alloy. DMLS alloy has a more homogenous and more compact structure, compared to CCM. Metals, the alloy basis cons...

The potential of trading activity income to fund third sector organisations operating in deprived areas

In the United Kingdom, as in other countries, Third Sector Organisations have been drawn towards income sources associated with trading activities, but many remain reliant on grant funding to support such activities. Using a multivariate analysis approach and data from the National Survey of Charities and Social Enterprises, it is found that trading activities are used relatively commonly in deprived areas. These organisations are also more likely to attempt to access public sector funds. This suggests policy-makers need to consider the impact of funding cuts on Third Sector Organisations in the most deprived areas as Third Sector Organisations are unlikely to achieve their objectives without continuing support.

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 compared fit between conventionally laboratory-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 and compared to the CAD model. To assess the fit of AM and lab-produced devices, three upper and three lower conventionally fabricated acrylic base plates were compared to three upper and three lower plates. Silicone impression material was allowed to set between the casts and the base plates which filled any discrepancy between the two surfaces. The thickness of this silicone media was measured ten times at five different points on each base 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 baseplate 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. Originality/value This work is original. The authors do not believe any previous papers similar to the one submitted have been published.

Use of a cast flexible plate as a hinge substitute in a hinge-lock design removable partial denture framework

PURPOSE The use of a hinge for a removable partial denture with an opening labial bow was replaced by the design and construction of a flexible plate incorporated as part of a cobalt-chromium casting. METHODS Three similar prostheses were constructed and tested in vitro on an endurance test machine. Each test piece completed 12,000 opening and closing operations without fracture, which a previous study showed is a probable life cycle of a typical removable partial denture with a hinged section. RESULTS This plate provided sufficient flexibility to allow functional operation of the removable partial denture by a patient.