Milk Teeth Issue with 11 yr Child

[Pun2017]

Hi

My daughter is 11y old. Her lower 2 incisor teeth never fell off. (Rest of the teeth are mostly in place).

I got x-ray done and it shows that actual teeth did not exist and hence milk teeth were never pushed out.

How common is it? What is the reason and what are the treatment options available?

Her those 2 milk teeth are somewhat shaky now.

I am very concerned about the dental health of my daughter.

Any help would be deeply appreciated.

Thanks