This one is so obvious we didn't even think of it until mjarkiver wrote up his recent experience at the dentist. We've all been there before, where a section of a tooth is to be replaced. Typically, the remaining surface on the tooth is prepped by leveling and smoothing. Then a mold is obtained by having the unfortunate patient bite onto a blobby mass of sticky goop, thus embedding a 3D rendering of your remaining tooth. This blob is then sent off to the "tooth fabber", who then sends a manufactured tooth back some days or weeks later.

But what if 3D technology was applied to the situation? mjarkiver had exactly that experience. While in the dentist's chair he was 3D scanned, and the resulting 3D digital tooth model was sent to an onsite 3D printer for immediate manufacture:

They did a couple scans with a 3D camera tool, and bam, there was my tooth, which they then overlayed with the correct “tooth shape”, to create an exact 3D model of what the crown would look like. That image then got sent to a 3D printer.

Also, mjarkiver says something quite ominous, something we will all experience in the next few years:

The thing is, this was my first real, honest-to-goodness encounter, in a “day to day” context, with a 3D printer.

Via mjarkiver