I agree, parents can NOT let this happen. In fact, in a child’s mind, when the parents don’t act it is quite possible the child interprets this as nothing can be done because she is ugly, she does have ugly teeth, etc. and places the parents in an adversarial position along with the bullys.
By the time a kid actually tells the parents they’ve usually already been bullied for a considerable time. Further teachers ‘KNOW’ who the bullies are. Unfortunately the bullies parents are often bullies themselves.
In this case the police should have been brought in..and depending on what the states laws are against bullying the parents would know what to do in that regard.
But Imo the best avenue is to go right to the bully with other parents. Get him/her alone and put the fear of God in them.....works every time!