Will removal of a crown from a live tooth damage the nerve? (Photo)

Thanks for your question! Anytime a dentist works on a tooth there is the possibility for further nerve trauma. It won't necessarily cause the need for a root canal, but it is a possibility. It's up to you to weigh the pros and cons of getting the crown redone vs repaired. The repair might not be as strong (it may chip or come off), and it may or may not improve the shade to your standards, however it is kinder to the nerve and if it doesn't work you can still get the crown redone at that point.
 Also, make sure you give your gum tissue plenty of time to heal before addressing the black triangles. These can take a long time to fill in after having crowns placed. After a few months, if they haven't filled in then you can consider the crown repair/replacement to fill in the area OR treatment with dermal fillers to plump up the tissue! I hope this helps.