The Malice of Raspberry Seeds
Sorry for a period of quiet, I've had a bit of a tooth ache and been trying to book a visit to a dentist. It's all because raspberries are coming in season, and I've been enjoying Eton messes under the guise of healthy eating. (It's nothing to do with gnashing of teeth over the baffling election results... honest.) But that also means I've been jamming raspberry seeds in my perfectly shaped molar-dimple-raspberry-seed-receptacle - resulting in that jarring hellish sensation of teeth meeting in an unexpected way. Similar to M. R. James' tale of The Malice of Inanimate Objects, when a similar jarring is experienced on using stairs, and:
"as age increases, the extra step on the staircase which leads you either to expect, or not to expect it."
And he then says:
"we have to acknowledge with gloomy resignation that our world has turned against us... The word is passed round, and the day of misery arranged."
Why are teeth so maddeningly insistent on attention when they feel wrong? Most of the time, they don't communicate at all.
Admittedly, one of the great achievements of mammalian evolution is a long term close meshing of teeth. Reptiles make do with a fairly infinite series of replaceable but simple peglike teeth - with the philosophy that the teeth can just lop food into chunks and swallow it whole. And if a tooth falls out, well another one will pop up to replace it as quickly as in whack-a-mole.
But for us mammals, any disturbance to this natural order of teethy things, for instance by an errant raspberry seed, can be maddening. And yet, we have all quite happily and unawaredly held twice as many teeth in our jaws and lose teeth with barely a thought. I will remind you of this with the compulsory nightmare image of a child's skull who is in the process of loosing their milk teeth (from the J A Fairfax Fozzard collection. See more information here, hare, here).
This is all part of the wonderful process of keeping sets of perfectly meshing teeth for a decade or so (which we have extended to a good half century for some poor teeth - hence my sensitive, filled molar giving my trouble.)
This turnover of teeth is terribly convenient for archaeologists who use juvenile skulls to help estimate tooth wear rates in a population - and so diet composition and clues about culture - clues about how much food is cooked and how much is grit.
You may not recall but your first set of adult molars erupt at around 7 years old. (Though you may, like me, have sold them to the tooth fairy, and then later found your parent's stash of your teeth, and resold them again and again!) The second set of molars come through later, at around 12 years old, so the amount of wear on the first molar in a child's skull combined with their estimated age give a good indication of tooth wear per year.
This skull in the Duckworth collection (and presumably previously from the Cambridge Museum of Anatomy) shows a molar sitting around in the jaw, ready to erupt. (Though, Americans, you can buy your own copies here and here. All the best things are for sale in America.)
Ready for when that second set of molars have worn down too, the wisdom teeth pop out sometime around 20 years old. Historically, these extra teeth could have been a lifesaver, as other teeth were worn down to the soft, pulpy, tender dentine - the brown bits in the teeth of this Roman skull's mouth (ouch).
Of course, life isn't so simple. Since the days of the caveman when tough things like bugs and trees, were your food, skull and jaw shapes have changed. We don't always have room for wisdom teeth to come through, causing more pain and inconvenient trips to the dentist.
And, of course, anything in our DNA that makes repeated things will go wrong sometimes, in this case, hyperdontia. Google it. Enjoy the nightmare images of how many teeth can grow in your mouth.
(Note, this is different from teeth growing in other parts of your body. Instead, for your broad education and further nightmares, google teratoma and for the gentlemen out there, vagina dentata.)
Meanwhile, I've off to use the floss. Both mental and dental.