I remember chewing ice sitting next to my grandfather when i was 8 years old. I am now 62 years old and still chew ice everyday . I still have my teeth and they are in excellent shape. Maybe my family just have good strong enamel or maybe the author is full of shit.
Teeth can repair themselves.
If they get damaged, it doesn’t matter if they repair themselves.
Everybody’s teeth get damaged. If a person has good teeth, it’s because his body repairs them.