Bones protruding from our fleshy gums. Washed with bacteria. Crevices hiding all manner of gunk.
Devices for tearing at other animals' flesh. And chomping plants.
The opening quote from the Secret Lives of Dentists sums this up perfectly:
Teeth outlast everything.
Death is nothing to a tooth.
Hundreds of years in acidic soil just keep teeth clean.
A fire that burns away everything else, hair and skin...
even bones, leaves your teeth dazzling.
Life is what destroys teeth.