Does being immortal include immortal teeth?

Thor is not immortal. He can be killed. And Odin was old man, long grey hair and at times infirm. So yes, Thor had to brush and floss.

But he is not prone to tooth decay the same we we humans are. It takes ages for him to get a cavity.

“Immortal” simply means not dying. You could 206 years old, unable to leave your bed, toothless blind and withered, and be immortal.
The Norse gods, as interpreted by Marvel, are just long-lived aliens.

Εverything is included.

The teeth eventually go, but the hair remains magnificent!

Plus then you can fly.

Yes, in that instance, teeth are immortal. Brushing and flossing are a must for appearance sake. They would have to be immortal since teeth are the weakest link in the body. My grandmother, who died at the age of 96, had all of her teeth and not one cavity! (Supposedly due to high natural fluoride levels in the water of western Oklahoma where she and her family lived.)

That’s amazing @kritiper. Was the rest of her family that way?

@Dutchess_III I would bet they were. Can’t say for sure.