Can Porcelain Lumineers Be Placed over Existing Porcelain Crowns?

Lumineers and non-prep restorations can be bonded to crowns. However, I do not recommend this method because it will add bulk to your teeth and make your teeth appear to be a lot bigger than they are. The best option is to remove the crowns and have Cosemetic Emax crowns placed. Good luck!

No point placing veneers over crowns, just replace the old crowns with Emax porcelain crowns and enjoy another 15 years problem free dentistry.

Actually, I had one of my patient's ask me the exact same question this week.  This isn't something I've done before, which is exactly what I told my patient.  It's also more expensive to place Lumineers than to just replace existing crowns in my office.  Even though lumineers can be as 0.3mm thin, the final result will still look a bit more bulkier which can be unesthetic.  Also we have no idea how well Lumineers will bond to porcelain, this isn't a procedure that the company advocates.  So why perform a procedure that's more expensive and also not very predictable?  I would recommend to just to replace the existing crowns if the shade really bothers you.  Good Luck!