Porcelain Veneers over dental implant crown on front tooth? (Photos)

From your smile photos, it seems like a large discrepancy between the gum symmetry and since you have a high lip line, it obviously shows. The porcelain veneer over the crown is really not the answer! 
Possibly redo drown and at the gum line place pink composite to blend to your gums, the result will be better. Your best bet to seek a periodontist advise, to see if there is a way to reshape the gum, and augment, or possibly lower your lip line !
Best of luck!

Your best bet would be to consult a good cosmetic dentist to evaluate your whole situation: Tooth Size, Space Size, Bite, Function and Esthetics.To close the gap, or even to reduce it, you need to treat the tooth on either side of the space. Other teeth may also need to be made wider to create abeautiful smile.

Yes you can have a crown veneered are replace the implant crown. You likely had a lot of bone loss and it can be very difficult to promote the body to regrow bone in the front, so your dentist did the best with pink porcelain to mimic the gums.  There are stains that could be used to modify the shade and you could possibly reduce the crown and re-cover with a veneer but it will be very dentist specific and a challenge for anyone.  I would suggest a dentist who uses CEREC as they could fabricate and stain right there chairside as it may be hard to work with an outside lab.

Hi:
Sorry to hear about your situation.  There is a possibility of getting a porcelain veneer over the crown to handle some of the problems you are discussing.  My suggestions is to consult with an experienced cosmetic dentist.
Best,
Dr. Maddahi

Dear Sarah, Thank yo for providing these photographs. Your problem is particularly complicated. I understand what was done for you and what the dentist tried to accomplish. I also understand your disappointment. To give you the results that you want which are ones that are spectacular, you really need to see someone who understands state of the art techniques and materials. I have such a team here in Chicago, but for someone living in Brooklyn, I would highly recommend Dr. Dennis Tarnow. He practices in Brooklyn and teaches at Columbia. Good luck, Dr. Neal