We describe state-of-the-art software and hardware requirements for the manufacture of high quality medical models manufactured using medical rapid prototyping. The limitations of medical models, the source of artefacts, and their physical appearance are illustrated along with remedies for their removal. Medical models were built using predominantly stereolithography and fused deposition modeling at both institutions over a period of 6 years. A combined total of 350 models have been produced for a range of maxillofacial, neurosurgical, and orthopedic applications. Stereolithography, fused deposition modeling, computerized numerical milling, and other technologies are described along with computer software requirements. A range of unwanted artefacts that create distortions on medical models have been identified. These include data import, computed tomography gantry distortion, metal, motion, surface roughness due to support structure removal or surface modeling, and image data thresholding. The source of the artefact has been related to the patient, imaging modality performance, or the modeling technology. Discussion as to the significance of the artefacts on clinical use is provided. It is recommended that models of human anatomy generated by medical rapid prototyping are subject to rigorous quality assurance at all stages of the manufacturing process. Clinicians should be aware of potential areas for inaccuracies within models and review the source images in cases where model integrity is in doubt.
1 August 2006 in The Journal of Prosthetic Dentistry
Objectives: To evaluate the accuracy and reproducibility of a three-dimensional (3D) optical laser-scanning device to record the surface detail of plaster study models. To determine the accuracy of physical model replicas constructed from the 3D digital files.
We review the use of additive manufacturing (AM) as a novel manufacturing technique for the production of milli-scale reactor systems. Five well-developed additive manufacturing techniques: stereolithography (SL), multi-jet modelling (MJM), selective laser melting (SLM), laser sintering (LS) and fused deposition modelling (FDM) were used to manufacture a number of miniaturised reactors which were tested using a range of organic and inorganic reactions.
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.
1 March 2005 in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
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.