Crowns cover the entire surface of your tooth. They are used to protect existing teeth and/or improve their appearance. They are usually made of porcelain and may have a gold core. To fit the crown your dentist will reduce the size of your existing tooth to make enough space for the crown and then make a mould for the dental technician. Your dentist will fit you with a temporary crown until the dental technician has made yours. Your dentist will cement the crown into place.