Abstracts

Wim Michiels, Materialise, Belgium
Update on Rapid Implant Manufacturing

In September 2007, the first Rapid Implant Manufacturing Forum was organized in Leuven. During that event, several speakers presented their experiences on this topic. A lot of it was still theoretical, experimental work on a single clinical case.

April 2010: the fourth version. Several clinical cases have been concluded in the meantime, some of which have been published. Such progress is not a coincidence: the machines, materials and software technology have evolved and with them the awareness of what is needed to make implants correctly and responsibly through additive manufacturing . This “sleeping giant”, as it’s been called, has been a major research focus for several years.

The presentation will highlight the role Materialise has played throughout the years and trace the evolution that eventually led to today’s technology. The current state of the industry, machines and materials will also be covered by other presentations in the Rapid Implant Manufacturing Forum. Here we’ll focus on Materialise’s experiences: the kinds of cases have that have been completed, and our role in them; which software solutions have been used and developed; how we’ve facilitated the process; what we’ve learned in terms of quality. Through these discussion points, the presentation aims to assist and inspire anyone interested in “Rapid Implant Manufacturing”.

Finally, we’ll take a cautious look at the future.

Martin Bullemer, EOS Gmbh, Germany
Additive manufacturing of medical metal materials

Additive manufacturing has matured from the early days of rapid prototyping to a serious alternative manufacturing method for high value metal parts. The present material selection includes many materials commonly used in various industries and the properties are in the same level with conventionally manufactured materials. Cast properties are mostly met and often even wrought ones. More data is available for the designers to use their imagination in creating designs for better performance.
In the regulated industries such as medical the route to manufacturing is complicated. It is not enough to prove that standardized material properties are met. They have to be met every time. Most of the part properties are created in situ in the machines and therefore careful process control is essential. Medical legislation requires also biological safety from the additive products. The presentation describes the EOS approach to cope with these requirements.

Philip Kilburn, 3TRPD, UK
“Facemaker” : Investigating clinical benefits of Layer Manufacturing for Maxillofacial Therapies

The “Facemaker” project was a DTI (UK Department of Trade and Industry) funded project that started in 2006 and was completed mid 2009. The project partners were 3T RPD Limited, Loughborough University, Queens Medical Centre Nottingham and Delcam plc.
There are approximately 30,000 patients per year in the UK requiring maxillofacial therapies, resulting from congenital conditions, surgery or trauma. Current therapies are dependent upon craft based methods that are often distressing to the patient and have not changed significantly in over 40 years.
The “Facemaker” project investigated and developed systematic techniques and business models that integrate computer imaging, reverse engineering and layer manufacturing processes to enhance patient therapy. The aim of the project was to develop techniques and processes that could be adopted by maxillofacial technicians without having to learn how to use a high-end CAD system, nor battle with the world of CAD and layer manufacturing.
The approach taken in the “Facemaker” project was to break down the process into 3 distinct areas – Data Capture, Data Processing and Layer Manufacturing Techniques. The project investigated each of these areas with the aim of improving and simplifying each process to improve clinical results and reduce patient trauma.

Emmanuele Magalini / Pierfrancesco Robotti, Eurocoating, Italy
Rapid Manufacturing validation for the medical field

Rapid Manufacturing methods allow to product parts quickly and in almost complete freedom of design. When Laser or ebeam manufacturing are considered for production (not only prototyping), great attention must be put in material characteristics and final pieces qualification; in particular in the medical field.
To reach this target, a complete qualification in agreement with applicable standards was performed: tensile properties and fatigue behavior were investigated on coupon bars; porous structures were analyzed by either mechanical performances (adhesion and compression) and morphometric analysis (pores and struts dimensions). Moreover tolerances against design and post-treatments were investigated. Finally in vitro and in vivo test were performed to attest porous networks capability to promote bone tissue ongrowth and ingrowth.

From a serial production point of view it is really important to guarantee process stability and results repeatibility, according to international quality systems. In our case this issue was accomplished by checking chemical-physical characteristics and mechanical performances periodically. Efforts were dedicated to reach process reliability and validate materials characteristics consistency batch by batch. Verifications were performed both on powder raw materials (chemical composition and microscopical analyses) and manufactured parts (mechanical performances and chemical composition). Other studies have also considered parts properties against powder ageing and process stability against working parameters shifted from optimized settings.

Professor Dale Geoffrey Howes, P-I Branemark Institue South Africa, South Africa
Rapid Design and Manufacturing of Implants – Research and Development in South Africa

The advent of rapid prototyping and now rapid manufacture is revolutionising craniofacial reconstruction.

Craniofacial defects present in many different shapes and sizes, created in a controlled matter by craniofacial surgery for oncology etc. and uncontrolled in trauma, including gun shots and battlefield injuries.

Custom craniofacial implants therefore vary greatly in the biomechanical demands placed upon them, dependent on the form and function required of the obturation, its required life and purpose of the implant.

These implants vary from the non functional to those designed to reconstruct facial parts and carry occlusal load.

This sometimes places unreasonable demands on the designers and manufacturers of custom implants. They need an intimate multidisciplinary understanding, including medicine, surgery, dentistry, technology, biomechanics and, of course, the required software. This in turn, therefore, requires excellent industry understanding and cooperation in software development and training.

This lecture will highlight many of these issues from a South African perspective with the challenges within a violent multisocial community and a developing emerging market.

Peter Mercelis, Layerwise, Belgium
Title has to be confirmed still

Abstract will be added later

Dr. Siu Yan Mak, Biomet Europe, UK
Evaluation of mechanical and tribological properties of DMLS deposited medical-grade CoCrMo

DMLS is an additive manufacturing technology which involves fusing metal powder into a solid part by melting it locally using a focussed laser beam, allowing the production of complex implant geometries directly from 3D CAD data.

The increased design flexibility presents new opportunities for manufacturing of complex, patient specific orthopaedic implants and instrumentation designed to minimise surgical error and improve clinical performance. Furthermore, DMLS offers the potential for ‘demand based manufacturing’.

Cobalt-28 chromium-6 molybdenum alloy (CoCrMo) is widely used in orthopaedics due to its high strength, wear resistance and biocompatibility. The present study investigated the suitability of DMLS for the manufacture of CoCrMo orthopaedic implants. The dimensional accuracy, tensile, hardness, fatigue and wear properties of CoCrMo samples produced using DMLS were compared with conventional wrought and as-cast medical grades of CoCrMo.

Specimens directly manufactured using DMLS, without any post-processing, were investigated. Dimensional measurements made using a coordinate measuring machine (CMM) showed parts were produced with high accuracy. It was found that DMLS samples had higher yield strength than wrought bar and as-cast material with equivalent hardness and fatigue properties. The wear rate of the DMLS samples as determined using a pin-on-plate machine was slightly higher than wrought and as-cast CoCrMo.

Dr. Ir. Frederik Gelaude, Mobelife NV, Belgium
Personalized implant design for acetabular revision

An increasing need for patient-specific surgery plans and implant designs exists, as population grows older, and patients receive primary joint replacements at younger age and stay more active after intervention. Sooner or later, primary interventions will require revision surgery. And often, large bone defects are involved.
Since surgeons put high demands to implant stability, functionality and safety, they – starting from a specific degree of complexity on – turn from off-the-shelf implants to patient-specific pre-shaped implants.
A novel, validated CT-based computer-supported methodology can be applied to generate biomechanically justified implant designs for bone and joint reconstructive surgery. Each implant is evaluated in a fully patient-specific manner in dedicated engineering (FEA) software [Mobelife NV]. By linking with additive manufacturing techniques, implant design is practically unconstrained and can therefore be pushed to a next level.
Clinical cases of complex acetabular revision with major bone loss will be used to illustrate the applied methodologies and overall workflow, and to bring forward innovative implant design features. The latter comprises optimal anatomical implant outlining, bone defect filling structures, and optimal screw fixation. Screw fixation planning is linked to custom jig transfer technology [Materialise NV].
In conclusion, this presentation will demonstrate that complex bone defects can be treated adequately and efficiently, using the presented Mobelife® all-in-one implant solution which addresses both patient’s and surgeon’s needs.

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