[torinmr]

Could that also be related to diet? I'm guessing your grandmother practically never ate sugar if she was living on 200 grams of bread a day.

I've also heard that early modern humans had fairly good teeth for their age despite the presumed lack of dental care, presumably also due to differences in their diet from us.

[Cerium]

Diet is super important. I used to drink orange juice every day. I got a cavity every 6 months. I have stopped drinking orange juice and have not had a cavity since.

[filoeleven]

I just heard a radio piece about how basically all humans had Hollywood smiles (where the teeth lined up perfectly) until the Industrial Revolution, when our jaws began to shrink and there was no longer enough room for all the teeth. I didn't get to hear the part where they discussed/hypothesized whether the changes were due to diet or environment or something else.