Can Elongated Teeth Be Pushed Up into Gums?

Yes they can and it is a very important movement is some orthodontic treatments.  Since your son is 11 years old it may be best to wait till all the permanent arrive and then start his orthodontic treatment.  Be sure to go to an ADA recognized orthodontic specialist as these type cases are more difficult to manage and need the extra training of the orthodontic specialist.  I use the Damon System braces and we have good success with intrusion in these cases.  It also helps us to avoid permanent toot extractions and expanders  in most but not all cases.  On getting more consultations, keep doing it until you get a very good explanation that makes good sense to you.  Also ask to see photographs of similar cases that this orthodontist has personally treated and read the reviews on the web.   I also recommend not going to "corporate" type dental practices where the same "hired gun" orthodontist may not even be there to finish you son's treatment.  I have seen patients have four different orthodontists during their treatment in some of these places and the treatment did not work out well at all.

Fact. Most definitely pushing a tooth in can happen and is often needed to obtain the healthiest, most attractive final result. We do this all the time, even with Invisalign. I'd say you are lucky to have found an orthodontist that has that cosmetic eye. Your finest dentist, Orthodontists and periodontist use intrusion to help move teeth, bone and gums into more ideal positions for better long term health. It's a funny concept I know, but it can be done.