Crowns or caps are protective coverings placed over damaged or malformed teeth. The crown can be made of metal such as gold, porcelain bonded to metal, or all porcelain. On the first dental visit the tooth must be prepared for the crown and then an impression is taken. A precise model of the tooth is made from the impression and the dental laboratory makes a crown that fits the model very precisely. It usually takes from two to three weeks to make the crown during which time the prepared tooth is fitted with a temporary crown. This prevents the prepared tooth from being sensitive or suffering further damage. On the second visit, the temporary crown is removed and the new crown is tried in. If the crown fits properly and meets the expectations of the dentist and the patient, it is permanently cemented on the prepared tooth. No other dental restoration will last longer than a crown and most crowns give decades of good service.