ANSWER - Great question! The possibilities are endless though I suppose it depends on what end you are trying to achieve. I'm going to assume that you want to use the teeth for magic related to the child herself and the most logical thought that comes to mind is using them for the purpose of protection. The easiest way to do this would be to string the teeth together onto a chain and use it as amulet to invoke the happiness and innocence of youth. Your daughter could keep it all her life and wear it on occasion as a link to her childhood self.
Another idea would be to make an infusion of the teeth. Any mildly acidic liquid (cola, lemon juice, vinegar) would dissolve the teeth and the fluid could then be bottled and used to anoint your daughter at times in her life when she feels she needs additional protection.
You could also consider burying one of the teeth on the family property as a link to connect her with the heart of her home and as part of a magical imperative to always draw her back safely toward the family.
Finally I would suggest that you could keep one of the teeth yourself, perhaps safely contained in a locket worn on your person so you can continually lend your own protective energies to your daughter regardless of where she may end up in the world.
Image - I found this on Twitter the other day and found it disturbingly fascinating.