Rapid Prototyping Applied to Maxillofacial Surgery

Abstract

What is rapid prototyping (RP)? The word prototyping was first used in engineering to describe the act of producing a prototype, a unique product, the first product, or a reference model. In the past, prototypes were handmade by sculpting or casting, and their fabrication demanded a long time. Any and every prototype should undergo evaluation, correction of defects and approval before the beginning of its mass or large scale production. Prototypes may also be used for specific or restricted purposes, in which case they are usually called a pre-series model. With the development of information technology, three-dimensional models can be devised and built based on virtual prototypes. Computers can now be used to create accurately detailed projects that can be assessed from different perspectives in a process known as computer-aided design (CAD). To materialize virtual objects using CAD, a computer-aided manufactory (CAM) process has been developed. To transform a virtual file into a real object, CAM operates using a machine connected to a computer, similar to a printer or peripheral device.13 In 1987, Brix and Lambrecht used, for the first time, a prototype in health care. It was a three-dimensional model manufactured using a computer numerical control (CNC) device, a type of machine that was the predecessor of rapid prototyping.6 Some rapid prototyping machines had already been in experimental use in the 1970s, and computed tomography (CT) was invented in the 1960s by Godfrey N Hounsfield, an electronic engineer, in collaboration with Allan McLeod Cormack, a physicist. However, it was only in the 1990s that an actual three-dimensional model was built to reproduce the anatomy of a patient based on CT images obtained during that patient’s examination4, thanks to advances in CT scanner quality and the development of specific software for this purpose. In 1991, human anatomy models produced with a technology called stereolithography were first used in a maxillofacial surgery clinic in Viena.16 Prototyping was developed to respond to the need to test functionality, ergonomics, shape, adaptation and design in production engineering, an area in which the term prototyping is