E-max crowns are made from Lithium Disilicate glass, while zirconia crowns are made from zirconium dioxide. Both are ceramic products and are durable. E-max, however, is more translucent than zirconia. If you have bruxism, choose zirconia. E-max may give up under extreme pressure. Then, if you are masking the front of your mouth, choose E-max. They match your natural teeth better. E-max may cost you more than zirconia in many parts of the world.