D.B.
None of us can see the xrays or any damage (or lack of it) up in the gums. What you do when you are not sure is that you go get a 2nd opinion. Take the xrays with you (either the films or the images on a disk) so you don't have to pay for a second set. You can ask your dentist for a referral to another dentist for a 2nd opinion (no good dentist or doctor will oppose you seeing another specialist), or you can ask your pediatrician for a name of a pediatric dentist.