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Mine does resin printing. I have two crowns that were printed and they feel 10x better than my old porcelain crowns.I couldn't help but note that my dentist used a scanning wand to scan my ground down tooth to make the inner surface of the crown.Boy I was wishing I had his technology.I jokingly asked him if he could print some model trains for me..... and he said his only does teeth.
Now I'm wondering how a printed part would hold up while being used a master in a vulcanizing mold for spin casting white metal (I cast using Britannia Metal -LEAD FREE Pewter Alloy- 92 Percent Tin). For the organic rubber molds I use, it'll need to take 330 degrees while under 2500 to 3500 psi for about 35 minutes. Next warm day we get around here, I'll have to try it. If this does work, it'll open the door for all kinds of stuff that I've wanted to do (like steam loco frames).
I had a crown made from a 3D scan few years ago, The dentist kept scanning the ground down tooth with a wand for quite some time and the software kept forming the 3D model. But I think that dental scanner is specifically made for producing featureless organic shapes, rather than objects with lots of flat surfaces and small and distinct details (like our models). That would explain your dentist's response. The crown itself was not 3D printed but machined by a small NC milling machine from a block of special ceramic which after machining was put in an oven and fired to be hardened. But that was few years ago so the technology could have changed since that time.
I was recently in this business on the engineering side of things. There are a few methods out there for dental scanning. I once tried to scan a small Delrin gear using a $50,000 laser dental scanner. It didn't work out too well because that type of scanning is based on reflectivity of the laser. There are some scanner sprays you can use on the part to be scanned to make it reflect properly but you have to know what you are doing. The software is the key in putting all that data into a 3D solids model.The method you two describe is actually "photo scanning". The wand doesn't use any type of laser but it is actually a small camera that captures snap shots very quickly. The software then pieces the images into a 3D solids model. The reason why it takes some time is that the dentist needs to move the wand around a few times to absolutely capture all the nooks and crannies of the tooth in the confined space of your mouth. If the wand can't see that area, it will not be captured and you'll end up with voids in the model.
The polling pockets were tapered, but the slicing stepped them. I quick twist with a drill bit will fix that.