I'll point out here that when you have a silver filling replaced they don't actually "remove" the filling... at least, not how I expected. They basically jackhammer it into tiny pieces and suction it out.
About an hour into the procedure the dentist says to the assistant something like "Wow, it's gone through the side of the tooth"; and then they talk about how weird it is as he keeps drilling away. He finishes that, and then pulls out a matrix band and attaches it to the tooth. Since I had no idea what it was at the time I was thinking he was going to pull the tooth. But then he left it attached, and the band retainer (or whatever the arm is called) was sticking out of one side of my mouth, and the suction tube the other.
Then we had several rounds of medicine, filling material, epoxy, light gun; removal of the matrix band and suction tube, and abandonment of me.
After a minute or two the assistant came back (we're at 90 minutes of a 10 minute procedure at this point); and I asked her about the band, and what was weird. So she explained to me that when the dentist had jackhammered away the filling, 1/4 of the tooth was hollow. The thin shell was then removed, and the posterior cheekside (in this case dexter) cusp is made entirely out of the epoxy/plaster/whatever.
Then he came back and shaped it a bit, so that it's more tooth-shaped; and then he was done so the orthodontist came over for my adjustment (and not to mention that the dentist wanted the wire off while doing the procedure). Muttering to herself the whole time about how long the procedure had taken; but she wasn't the one who spent an hour and a half with their head being the closest part of their body to the floor. After it was all said and done it took another 5-10 minutes before I could walk.
And I guess there's a mild chance that the nerve in the tooth gets damaged when doing this; so I'm supposed to call if I start experiencing any pain from that tooth.... what's left of it, at least.