Computer-aided design and computer-aided manufacturing make you think of vast robotic arms assembling cars, but did you know that both have a growing presence in dentistry, changing the way dentists can operate and allowing the decentralisation of parts of the design and fabrication process out of regional laboratories and back into local clinics.
With restorative dentistry, the challenge has always been to provide seamless yet sturdy interfaces between prosthetics and natural living teeth or bone. The production of such prosthetics is therefore highly dependent on geometry and accurate measurements. With the traditional method this was done through dental moulding; a silicone mould would be taken in the clinic and then couriered to a dental laboratory. With them a plaster-cast replica of the area could be made, as the measurements taken of the replica for the prosthetic or insert were known. After fabrication, the prosthetic could be fitted to the plaster mould and adjusted to try to gain the best possible fit.
3D scanners have changed much of this, not only is the process of moulding itself really irritating as time has to be given for the silicone to set somewhere between 5 and 30 minutes, but patients often find it uncomfortable, particularly compared to the seconds required to capture a scan. The communication of a scan via the internet is so much more convenient than delivery of physical moulds, which always have with them a risk of distortion and warping during transit.
The entry of CNC desktop milling machines into dental surgeries is a relatively new phenomenon that has only just started to creep into the early adopters and tech-focused clinics. It allows the automated milling (cutting and grinding) of pre-made blank blocks of porcelain-polymer composite, with no previous manufacturing experience. A dental nurse can set up the machine and run it and after a few minutes, the finished piece can be collected from the machine. When paired with good quality design software and the appropriate staff training, it allows a normal sized dental clinic to produce its own crowns and other small oral prosthetics. Many of these surgeries have used this to offer same day crowns or onlays, something that would only have been possible in dental hospitals or universities that had on-site fabrication facilities.
Use in orthodontics
Both the computer design and 3D scanning come together with Invisalign London where patients’ teeth are scanned and a simulation is used to predict the coming treatment, allowing patients to see the future results of the care before they commit to it. The aligners are manufactured off site using UV resin and 3D printing technology, but how long will it be until those printers themselves find their way into the clinic? At the current rate, it seems that more and more decentralisation should be expected and with issues concerning supply chains and uncertainty affecting many medical fields, dentistry is the one that seems to be leading the way in freeing itself from the many obstacles and pitfalls which can beset it.