Dental crowns, also known as dental caps, cover damaged or discolored teeth. Crowns cover the entire tooth, starting at the gum line. They are usually made of gold, porcelain or a combination of both.
Though crowns can be used to improve the appearance of a tooth, they are not primarily cosmetic devices. Dentists recommend crowns to protect or strengthen a weakened tooth or to restore a disfigured tooth to its original shape. ﾓCappingﾔ a tooth requires buffing away part of a tooth to make room for the crown so dentists often discourage it as a cosmetic method unless the teeth are damaged.
Crowns strengthen teeth by binding the sides of the weakened tooth together much the way a splint holds together a broken bone. Large fillings taking up over a third of the tooth may weaken that tooth over time; crowns are often used in cases where such weakened teeth threaten to break.
There are three types of crowns: metal ceramic or porcelain fused to metal (PFM). Metal crowns are used mainly on the back teeth and are made of gold alloy palladium nickel alloy or chromium alloy. Ceramic crowns and PFM crowns both look like natural teeth though PFM crowns are stronger. For obvious esthetic reasons they are better choices for capping front teeth. The ﾓcappingﾔ procedure takes place under anesthetic. Because the crown is about two millimeters thick the dentist first shaves this same amount off your existing tooth to void awkward-looking oversized teeth. The dentist will also re-shape your tooth into a form upon which a cap can easily sit. He or she will then make a replica of the tooth. Usually this replica will be a putty mold. This mold is then sent to a laboratory where the crown will be made based on this mold. In the case of a porcelain crown the dentist will choose a shade close to the color of the surrounding teeth. You meanwhile will return home with a temporary acrylic crown. You will return about two weeks later to have the crown fitted and once both you and your dentist are satisfied with the ﾓlook and feelﾔ of the crown cemented over your original tooth. If a tooth is severely damaged your dentist may decide to first perform a root canal a treatment where the dentist removes inflamed or infected tissue from the inside of your tooth. He or she must then build a ﾓpost-and-coreﾔ foundationﾗa foundation for the crown to sit on.