CAD/CAM: an essential partner in modern dentistry
Introduction:A brief history
Initially developed in the aeronautical and automobile industry in the 1960s, in order to standardise the production of routine, repetitive forms, CAD/CAM’s dentistry application was considered an ambitious and somewhat fanciful project, each prosthetic piece being unique and specific to the individual patient.
In 1973, François Duret had the idea of transferring this concept to making dental prosthetics, and thus became the inventor of dental CAD/CAM, the foundations of which he discussed in his paper “Optical impression”.
Thanks to the work of F. Duret, CAD/CAM was born and went on to revolutionise the world of dentistry.
This technology has continued to evolve and improve ever since in the field of odontology, carving itself a reputation as an indispensable tool in the digital age.
The first part of this article examining dental CAD/CAM will be dedicated to a definition of the CAD/CAM chain and its various components and their characteristics. We will then look at the various classifications within the dental CAD/CAM chain, and discuss its applications, benefits and limitations.
Definition
The dental CAD/CAM chain (Computer Aided Design / Computer Aided Manufacturing) is a collection of coordinated technological resources for recording (acquisition) analogue clinical data in digital format and virtual modelling, before producing a tangible bespoke medical device.
It therefore concerns all odontology specialties requiring bespoke medical devices.
Digital flows and components in the CAD/CAM dental chain
A full CAD/CAM dental chain comprises 4 links separated by interfaces:
1st Iink: Data acquisition
Acquisition involves digitising clinical data, followed by a processing stage. This can be done directly in the mouth using an intra-oral camera, or by scanning plaster moulds or impressions.
2nd link:CAD
CAD (computer aided design) is the process of creating virtual objects using a graphic representation. It includes a stage prior to the prosthetics design stage involving the “post-processing” of points obtained during the acquisition stage using optical impressions. At the end of this stage, the virtual model appears on the screen after digitisation.
3rd link:CAM
CAM (computer aided manufacturing) is the process of making objects; transforming a virtual object (created by CAD) into a material object. This involves dedicated software to generate toolpaths, determining the tools’ positions during manufacturing.
4th link:NCMT (Numerical control machine tools)
This is the fourth and last component in the CAD/CAM dental chain, and is responsible for manufacturing.It’s a programmable machine tool fitted with a numerical control.
The manufacturing process is conducted either:
–By subtraction (by removing materials): we talk about subtractive manufacturing, primarily machining via milling.
–By addition (by adding materials): we talk about additive manufacturing, better known as 3D printing. The main additive processes for formatting are stereolithography (SLA), fused deposition modelling (FDM), laser micro-fusion (LM) and selective laser sintering (SLS).
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