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Article
Publication date: 17 October 2016

Sean Peel, Dominic Eggbeer, Adrian Sugar and Peter Llewelyn Evans

Post-traumatic zygomatic osteotomy, fracture reduction, and orbital floor reconstruction pose many challenges for achieving a predictable, accurate, safe, and…

Abstract

Purpose

Post-traumatic zygomatic osteotomy, fracture reduction, and orbital floor reconstruction pose many challenges for achieving a predictable, accurate, safe, and aesthetically pleasing result. This paper aims to describe the successful application of computer-aided design (CAD) and additive manufacturing (AM) to every stage of the process – from planning to surgery.

Design/methodology/approach

A multi-disciplinary team was used – comprising surgeons, prosthetists, technicians, and designers. The patient’s computed tomography scan data were segmented for bone and exported to a CAD software package. Medical models were fabricated using AM; for diagnosis, patient communication, and device verification. The surgical approach was modelled in the virtual environment and a custom surgical cutting guide, custom bone-repositioning guide, custom zygomatic implant, and custom orbital floor implant were each designed, prototyped, iterated, and validated using polymer AM prior to final fabrication using metal AM.

Findings

Post-operative clinical outcomes were as planned. The patient’s facial symmetry was improved, and their inability to fully close their eyelid was corrected. The length of the operation was reduced relative to the surgical team’s previous experiences. Post-operative scan analysis indicated a maximum deviation from the planned location for the largest piece of mobilised bone of 3.65 mm. As a result, the orbital floor implant which was fixed to this bone demonstrated a maximum deviation of 4.44 mm from the plan.

Originality/value

This represents the first application of CAD and AM to every stage of the process for this procedure – from diagnosis, to planning, and to surgery.

Details

Rapid Prototyping Journal, vol. 22 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 13 May 2019

Igor Budak, Aleksandar Kiralj, Mario Sokac, Zeljko Santosi, Dominic Eggbeer and Sean Peel

Computer-aided design and additive manufacture (CAD/AM) technologies are sufficiently refined and meet the necessary regulatory requirements for routine incorporation into…

Abstract

Purpose

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 regions. 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 aims to present a novel application of CAD and AM to a single-stage resection and reconstruction of fibrous dysplasia in the zygoma and orbit.

Design/methodology/approach

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.

Findings

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 ranged between −0.1 and −0.8 mm and that the majority of deviations were located around −0.3 mm.

Originality/value

Improvements are suggested and conclusions drawn regarding the design decisions considered critical to a successful outcome for this type of procedure in the future.

Details

Rapid Prototyping Journal, vol. 25 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 2 January 2018

Noor Abdullah Al Mortadi, Dominic Eggbeer, Jeffrey Lewis and Robert Williams

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…

Abstract

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.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 18 January 2016

Steffan Daniel and Dominic Eggbeer

This paper aims to present novel techniques for designing maxillofacial prostheses using computer-aided design (CAD) and additive manufacture (AM), focusing on the…

Abstract

Purpose

This paper aims to present novel techniques for designing maxillofacial prostheses using computer-aided design (CAD) and additive manufacture (AM), focusing on the integration of osseointegrated retention components. A fully computer-aided approach is considered as a major step towards reducing patient consultation time and an efficient workflow.

Design/methodology/approach

The workflow was illustrated through a phantom model. 3D laser scanning was used to capture the phantom anatomy and pre-fabricated geometric features, which enabled the implant positions to be precisely reverse engineered in the data. A novel CAD workflow was used to design the retention mechanisms and a mould. The individual components were fabricated using AM. A definitive silicone prosthesis that incorporated a bar/clip retention mechanism was then fabricated.

Findings

The research demonstrated that retention components can be integrated into prostheses using appropriate CAD and AM technologies.

Originality/value

This study demonstrates the feasibility of a computer-aided workflow for designing facial prostheses that incorporate osseointegrated retention mechanisms. Novel techniques were developed to: digitise abutment details using custom scanning locators; design retention components; manufacture retention components using AM; integrate retention components into a CAD and AM prosthesis mould. This overcomes limitations identified in previously published cases and demonstrated significant potential to reduce patient consultation time and create a clinically viable process.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 March 2006

Richard Bibb, Dominic Eggbeer and Robert Williams

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…

Abstract

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 patient's 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 frameworks for specific individual patients.

Research limitations/implications

The study was based on a single design produced using two materials. Further studies are in progress to show that the results can be achieved on a regular and predictable basis.

Practical implications

This study provides some practical guidance for the application described and suggests that similar success may be achieved in related custom‐fitting applications.

Originality/value

The paper demonstrates the successful application of a novel approach to the design and manufacture of custom‐fitting dental devices.

Details

Rapid Prototyping Journal, vol. 12 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 9 March 2010

Richard Bibb, Dominic Eggbeer and Peter Evans

Maxillofacial prosthetics is faced with increasing patient numbers and cost constraints leading to the need to explore whether computer‐aided techniques can increase…

Abstract

Purpose

Maxillofacial prosthetics is faced with increasing patient numbers and cost constraints leading to the need to explore whether computer‐aided techniques can increase efficiency. This need is addressed through a four‐year research project that identified quality, economic, technological and clinical implications of the application of digital technologies in maxillofacial prosthetics. The purpose of this paper is to address the aspects of this research that related to the application of rapid prototyping (RP).

Design/methodology/approach

An action research approach is taken, utilising multiple case studies to evaluate the current capabilities of digital technologies in the preparation, design and manufacture of maxillofacial prostheses.

Findings

The research indicates where RP has demonstrated potential clinical application and where further technical developments are required. The paper provides a technical specification towards which RP manufacturers can direct developments that would meet the needs of maxillofacial prosthetists.

Originality/value

Whilst research studies have explored digital technologies in maxillofacial prosthetics, they have relied on individual studies applying a single RP technology to one particular aspect of a prosthesis. Consequently, conclusions on the wider implications have not been possible. This research explored the application of digital technologies to every aspect of the design and manufacture of a series of maxillofacial prostheses. Unlike previous research, the cases described here addressed the application of RP to the direct manufacture of substructures, retention components and texture. This research analyses prosthetic requirements to ascertain target technical specifications towards which RP processes should be developed.

Details

Rapid Prototyping Journal, vol. 16 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 18 January 2016

Ana R. Lapcevic, Danimir P Jevremovic, Tatjana M Puskar, Robert J. Williams and Dominic Eggbeer

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…

Abstract

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 consists of, form semilunar stratified layers, which are characteristic for the additive manufacturing (AM) technique. Hardness values of DMLS (mean value was 439.84 HV10) were found to be higher than those of CCM (mean value was 373.76 HV10).

Originality/value

There are several reports about possible use of AM technologies for manufacturing dental devices, and investigation of mechanical properties and biocompatibility behaviour of AM-produced dental alloys. Microstructure of Co-Cr alloy made with DMLS technology has been introduced for the first time in the present paper.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 25 September 2009

Richard Bibb, Dominic Eggbeer, Peter Evans, Alan Bocca and Adrian Sugar

The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to…

Abstract

Purpose

The computer‐aided design (CAD) and manufacture of custom‐fitting surgical guides have been shown to provide an accurate means of transferring computer‐aided planning to surgery. To date guides have been produced using fragile materials via rapid prototyping techniques such as stereolithography (SLA), which typically require metal reinforcement to prevent damage from drill bits. The purpose of this paper is to report case studies which explore the application of selective laser melting (SLM) to the direct manufacture of stainless steel surgical guides. The aim is to ascertain whether the potential benefits of enhanced rigidity, increased wear resistance (negating reinforcement) and easier sterilisation by autoclave can be realised in practice.

Design/methodology/approach

A series of clinical case studies are undertaken utilising medical scan data, CAD and SLM. The material used is 316L stainless steel, an alloy typically used in medical and devices and surgical instruments. All treatments are planned in parallel with existing techniques and all guides are test fitted and assessed on SLA models of the patients' anatomy prior to surgery.

Findings

This paper describes the successful application of SLM to the production of stainless steel surgical guides in four different maxillofacial surgery case studies. The cases reported address two types of procedure, the placement of osseointegrated implants for prosthetic retention and Le Fort 1 osteotomies using internal distraction osteogenesis. The cases reported here have demonstrated that SLM is a viable process for the manufacture of custom‐fitting surgical guides.

Practical implications

The cases have identified that the effective design of osteotomy guides requires further development and refinement.

Originality/value

This paper represents the first reported applications of SLM technology to the direct manufacture of stainless steel custom‐fitting surgical guides. Four successful exemplar cases are described including guides for osteotomy as well as drilling. Practical considerations are presented along with suggestions for further development.

Details

Rapid Prototyping Journal, vol. 15 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 18 January 2016

Sean Peel and Dominic Eggbeer

The purpose of this paper is to identify the key design process factors acting as drivers or barriers to routine health service adoption of additively manufactured (AM…

Abstract

Purpose

The purpose of this paper is to identify the key design process factors acting as drivers or barriers to routine health service adoption of additively manufactured (AM) patient-specific devices. The technical efficacy of, and clinical benefits from, using computer-aided design (CAD) and AM in the production of such devices (implants and guides) has been established. Despite this, they are still not commonplace. With AM equipment and CAD tool costs largely outside of the clinician’s or designer’s control, the opportunity exists to explore design process improvement routes to facilitate routine health service implementation.

Design/methodology/approach

A literature review, new data from three separate clinical case studies and experience from an institute working on collaborative research and commercial application of CAD/AM in the maxillofacial specialty, were analysed to extract a list and formulate models of design process factors.

Findings

A semi-digital design and fabrication process is currently the lowest cost and shortest duration for cranioplasty implant production. The key design process factor to address is the fidelity of the device design specification.

Research limitations/implications

Further research into the relative values of, and best methods to address the key factors is required; to work towards the development of new design tools. A wider range of benchmarked case studies is required to assess costs and timings beyond one implant type.

Originality/value

Design process factors are identified (building on previous work largely restricted to technical and clinical efficacy). Additionally, three implant design and fabrication workflows are directly compared for costs and time. Unusually, a design process failure is detailed. A new model is proposed – describing design process factor relationships and the desired impact of future design tools.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 19 January 2015

Frank Alifui-Segbaya, Jeffrey Lewis, Dominic Eggbeer and Robert John Williams

The purpose of this research paper is to compare corrosion data obtained from additive-manufactured heat-treated (HRx) and non-heat-treated (NHRx) cobalt-chromium (Co–Cr…

Abstract

Purpose

The purpose of this research paper is to compare corrosion data obtained from additive-manufactured heat-treated (HRx) and non-heat-treated (NHRx) cobalt-chromium (Co–Cr) alloys. Heat treatments are indicated as necessary in complex intra-oral framework production by additive manufacturing to remove accumulated thermal stresses. However, heat treatments have been linked to corrosion in cast dental alloys. Currently, there are few publications on this subject for laser-sintered dental alloys required for academic review.

Design/methodology/approach

Five rectangular specimens (n = 5), each with a total surface area of 10.27 cm2, were fabricated for the two groups. Specimens were immersed in an artificial saliva solution suspended by a nylon thread for 42 days at 37°C. Readings for Co, Cr and molybdenum ions released into the solution were obtained using an atomic absorption spectrometer at 1-, 4-, 7-, 14-, 21-, 28-, 35- and 42-day intervals at a detection limit of one part per million. Test methods are in accordance with ISO 10271.

Findings

Results showed a higher ion release in the HRx sample, statistically significant at 99 per cent confidence level (p < 0.01). A two-way ANOVA test conducted showed that there was a main effect of day and a main effect of finish, and there was also a significant interaction between these factors.

Originality/value

The study concludes that, although ion release in both samples was within the safe level recommended by ISO for the three major alloying elements, heat treatment, indeed, contributed extensively to the reduced corrosion resistance in the laser-sintered Co–Cr alloy. Further biocompatibility tests are recommended.

Details

Rapid Prototyping Journal, vol. 21 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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