Curse you, Denisovans!
This is a tooth.
Well, technically, I suppose, it's a drawing of a tooth. (ceci n'est pas une dent.) Still, it gets across the idea. A tooth has a particular shape vaguely like this, and, as all fools know, a tooth (at least the ones in the back) has two roots.
So gather ’round, it's time for a story.
Let’s set the Wayback machine to, like, 1999 or so. I had a root canal done on one of these. A root canal is a rather unpleasant procedure in which a hole is drilled in the top, the nerve inside and down the roots is reamed out and then filled in with...well, I don't know what it’s filled in with. Concrete, maybe. Something. And then a crown is stuck on the top.
Anyway, I had this done, and for years afterward every visit to a dentist was kind of a variation on the same theme:
Dentist: *takes X-rays.*
Dentist: *looks at the X-rays*
Dentist: "Ah, I see a root canal. Wait, hang on, there's a weird shadow. It looks kinda like...hmm, not an abcess, it's just...what is that?"
Dentist: *hammers on my tooth with a little metal thing*
Dentist: *Touches my tooth with an ice cube*
Dentist: “Does that hurt?”
Me: “Nope!”
Dentist: *shrugs* “Huh, weird. Whatever.”
That's our backstory. Our tale takes place yesterday, when I'm in an office working on having a crown (a different crown) replaced because it's failed. Cue the normal X-rays, “hmm that’s strange,” only this time, something changes.
This time, I have a dentist whose mind is fueled by the desire to Know. A dentist not content to shrug and say “weird, whatever.” A dentist illuminated by the blazing light of curiosity that dragged our ancestors from the trees and sent them across the savannah to invent tools like spears and slings and particle accelerators, all because “¯\_(ツ)_/¯” isn't a good enough answer. He’s like, weird, something strange here, let’s look further.
Now, molars have two roots. Everyone knows this. One tooth, two roots.
Except that he does a bunch of X-rays from different angles and guess what? Fuck me dead, that tooth I got the root canal on, it has three roots.
Three. Roots.
And the dentist who did the root canal, he missed that.
It happens, apparently. It happens more in some genetic groups than others, and it might be related, as it turns out, to interbreeding with Denisovans somewhere in our ancient Homo sapiens lineage.
Representative illustration
Loooong story short, over the past twenty-something years, that unfilled third root has been quietly accumulating cruft like old FORTRAN code, and now they need to fix it.
But apparently they don’t want to remove the crown-not sure why, but for whatever reason they have to leave the crown on, which is made of metal by the way, drill through it, and re-do the root canal.
Anyway, my dentist was all “This is way above my pay grade, you’re gonna need a specialist for this. Oh, if they can’t drill straight through the crown, the other option is to go at it from underneath, which means they drill a hole through your jaw into the bottom of the tooth, fix the root, then put a bone graft in the hole.” Which, I mean, I'm no medical professional, but that sounds straight out of a Stephen King novel. “The Toothening,” something.
So that’s a thing.