There is no “secret block” when it comes to CEREC. Any material can be used with Cerec chair-side or with Cerec In-Lab. This is a review of the possible materials using the chair-side system.
There are the standard monolithic ceramics, but there are exciting polychromatic blocks to use as well. Milling chair-side zirconia is even possible!
Some of my favorite materials are:
eMax CAD: lithium disilicate
TelioCAD: bis-acrylic for provisionals
Lava Ultimate: composite