Nothing specific happened to Madison Keys’ teeth as she grew longer ones just from genetic mutations.
They are completely normal and it is part of the hereditary mutations that some people grow larger teeth.
Not only the larger ones but there are people with smaller teeth as well.
It is scientifically reported that the genetic mutations for growing teeth sometimes alter slightly but it is not any kind of problem or disorder.
She used braces as a child to control her outgrowing teeth and now they look beautiful to justify her gorgeous smile.