A crown is a cap that encircles a tooth or fits over a dental implant. A crown can be made from many materials (they are often used to improve the strength or apperence of teeth). Because the crown is made for you, it will look as natural as possible and therefore fits with the rest of your teeth.
The dentist prepares the tooth to make space for the crown. A dental impression is taken of your teeth. This can be done by taking an alginate impression or by a digital scanner. Also the colour is chosen and the bite registered. The crown is made in a dental technician lab. A temporary crown is placed to protect the prepared tooth. When the crown is ready it is placed in the mouth and if the fit and the colour is as desired, it is then cemented in place.