The patient can not remove them. They may be of one piece (crown), of several pieces (bridges) or the entire arch. Metal-ceramic crowns are composed of a metal core and ceramic coated. Currently they are made from alumina or zirconium cores, too.
To make them it is necessary to reduce the teeth, take a silicone impression and sent it to the lab where it is made to finally be fixed in the surgery with a dental bond.