1. Some people lose their teeth because they can't speak and lack communication, because they have a lisp.
2, because he is too fat to lose weight, he is controlling himself to eat, otherwise he may dream of losing his teeth.
There is also a saying that a person's belief is not firm enough, and his confidence is shaken or lost, because his mouth is used to spread ideas, and ideas are the basis of beliefs, similar to the first point.