I think its horrible - its far too early to make that decision for your child. I think its something a person should make for themselves. "Expensive dental work" could mean only a few teeth impacted - the rest may be perfectly great. I see no reason to take them out.
For many children, my daughter in this case, it was an option, and was suggested. We didn't go that route but given both parents teeth and the dentist's assessment it would have been reasonable.
I think what your main concern is that such a drastic body modification should not be done in a flippant manner. I feel the same way about hormone therapy.
