Lumineers or similar type of resotrations (Lumineers are really just a brand name, like Kleenex is to tissue) can be bonded to porcelain crowns to camouflage crooked teeth. There is a debate on whether or not this is the best way to fix things though. I can tell you that many of my patients that have had old crowns and wanted them to look better, straighter, whiter, using newer materials. I usually remove the old crowns and replace them with a more esthetic all porcelain material. Often I find decay or leakage around these old crowns and replacing them becomes not only an esthetic advantage, but functionally a huge improvement. It is almost impossible for a dentist to know what is under a crown. Putting beautiful veneers over crowns could be risky. The other disadvantage to this method is that the bond to porcelain is not always predictible or successful. If you go forward with this method the bonding must be done very carefully.