Crowns are a cosmetic restoration used to improve your tooth's shape or to strengthen a tooth. Crowns are most often used for teeth that are broken, worn, or have portions destroyed by tooth decay.
Crowns are "caps" cemented onto an existing tooth which fully cover the portion of your tooth above the gum line. In effect, the crown becomes your tooth's new outer surface. Crowns can be made of porcelain, metal, or both. Porcelain crowns are most often preferred because they mimic the translucency of natural teeth and are very strong.
Crowns are often preferable to large, silver, amalgam fillings. Unlike fillings which apply material directly into your mouth, a crown is fabricated outside your mouth. Your crown is created in a lab from a unique impression made of your tooth. Using this impression a dental laboratory technician is able to examine all aspects of your bite and jaw movements. Your crown is then sculpted just for you so that your bite and jaw movements function normally once the crown is placed.
Large fillings, especially on the back teeth, do not hold up well. Breakage and cavities occur more frequently. Food trapping and gum diseases are more of a problem. Crowns strengthen a tooth, making breakage and cavities much less likely to happen and creating healthier gum tissue.