This was a gentleman that had two crowns done many years ago. They were made with the Empress 2 system which had the lithium disilicate core (Empress 2) and Empress 1 pressed on top of them. (Some Empress history on Empress is found here.) They were in good condition, but the patient never liked how long they were, and after bleaching they no longer matched the adjacent teeth.
Using CEREC’s CAD/CAM system and the newer and improved lithium disilicate material from Ivoclar-Vivadent, Emax CAD, they were easily replaced. The color match was much easier as well, because it was done in one visit.