If our permanent teeth will break , then , no teeth will formed , whereas , after breaking of milk teeth , then ,teeth will reform again. Why this happen so?

Dear student.

We, humans, are born with two sets of teeth milk teeth and permanent teeth. This is called diphyodont, where two successive sets of teeth are developed during the lifetime of the organism. The first set of teeth is deciduous and the other set is permanent. Once our jaws mature milk teeth are replaced by permanent teeth and there are no other teeth to replace permanent teeth. This is why permanent teeth do not reform again, whereas milk teeth do.

Regards.