(1) powder/liquid, glass-based systems; (2) machinable or pressable blocks of glass-based systems; and (3) CAD/CAM or slurry, die-processed, mostly crystalline (alumina or zirconia) systems. The authors believe it is important to classify glass-based systems this way because they have seen a greater correlation to clinical success (and thus failure) based on the processing techniques of these materials than based on their chemical or micro-structural nature within classes of materials. Specifically, machined blocks of materials have performed better than powder/liquid versions of the same material. - See more at: https://www.dentalaegis.com/id/2009/10/many-different-types-of-ceramic-systems-have-been-introduced-in-recent-years-for-all-types-of-indirect-restorations#sthash.4ItTOR4b.dpuf