Zirconia veneers reshaping. Do I have to remove all the crowns?

You have 2 options to add length to existing zerconia crown you want:!- Have another zerconia veneer fabricated and bonded to the existing zerconia crown, this can be done without removing your existing zerconia crown. Be aware that the bond of this new veneer is not ideal, and it is considered repair work.2- Redo your 2 front zerconia crowns, a better option. You get 2 new zerconia crowns with the exact length you want.Assuming that already your dentist has shown you how much length can be added to your front 2 crowns.On both procedures extra costs of redoing is involved.

to make longer crowns, it will depend on:
If it is a bridge where all the crowns are joined, it is necessary to remove them all.
if they are individual, just remove the ones you want to make longer.
Another option is not very safe, is to add material placed in your mouth whatever the scenario.

Hi:There is a possibility of preparing the two front crowns and placing a veneer over it to lengthen the teeth without removing all the crowns.Best,Dr. Maddahi

If all of the crowns are connected, yes, they would all need to be removed to change just one or two. You can't add length to zirconia crowns without redoing them completely.