Image Credit: http://www.cockeysvilledentist.net/
Recently, I broke yet another tooth which required - of course - another crown. But this time was different. Today, after my dentist did the standard tooth preparation, a licensed technician scanned my tooth using a hand-held 3D scanner and then downloaded the CAD file onto the computer right next to my chair. I got to watch her manipulate the 3D model - the dental office knew I have a 3D printing company, so they humored me. She explained how she first determines the borders and then calculates the bite (using a scan of the tooth's chewing mate). She then proceeded to determine the best tooth shape to ensure a proper rough fit.
The procedure used was a great example of a hybrid manufacturing process because once the file was ready, the tooth was made using subtractive instead of additive manufacturing. A block was milled to the correct size and then further reduced by hand through successive mouth fittings. Once the ideal fit was achieved, the uncured porcelain crown was baked for a mere 20 minutes and then glued permanently (hopefully) into my mouth.
It would have been really cool if it had been 3D printed, but honestly, this process took less time, so for now, that's good enough for me.