Teeth are amazing. One of the areas where human crystal formation happens. Our modern diets are horrible for teeth.

https://m.youtube.com/watch?v=t4RgBZlKlJI

Evolution expects us to grind away about a millimeter of our teeth while we are young by eating rougher things to make way for wisdom teeth, for example.

For healthy teeth, you should be very hydrated. If your mouth isn’t watering, you might not be hydrated enough.