Veneers and old implant tooth - what are my options?

I had an accident and lost my front tooth a while ago, so I got an implant, probably about 20 years ago. It's been great since, still had no problems with it. But now I want to improve my smile and I really want to get veneers. I talked to my dentist and he said that it's impossible to put veneer or lumineer over and implant crown. What are my options? Is replacing an implant crown to a whiter one is the only option? is it a bad idea to do so just to get veneers?