What are dental crowns?

Crowns, commonly known as Caps, are restorations that are placed by a dentist to restore a tooth to it's natural contour, beauty, and function. Crowns are placed for many reasons, such as a severely chipped or broken tooth, a tooth that is particularly sensitive to biting, or a tooth that has had a root canal. To prepare the tooth for a crown, the area is numbed and the tooth is shaped so that the crown will fit over it. Several different materials such as gold, PFM (porcelain fused to metal), or ceramic, may be used to fabricate the restoration. You and your dentist can discuss which is the best for you. Since placing a crown cannot be reversed, it may not be the first choice for a strictly cosmetic procedure such as changing the color of the tooth, unless the tooth is discolored due to having had a root canal in the past.

How is a bridge different than a crown?

A bridge is used to replace one or more missing teeth. It is placed by preparing one or more teeth on both sides of the space for a crown. A bridge is usually made in one piece, with the teeth which anchor the bridge (abutments) and the false teeth in the middle (pontic) being permanently attached with a very strong cement. Bridges, implants, and partial dentures (the three ways of replacing missing teeth) each have distinct advantages and disadvantages which should be discussed with your dentist.

Why do crowns fail?

Crowns fail for several reasons. Perhaps the most common is decay around the edge (margin) of the crown. This can happen even when the procedure has been properly performed. The second reason is due to failure of the visible part of the crown, such as porcelain fracturing or wearing through the metal on the chewing surface of the crown. Crowns may also need to be replaced for cosmetic reasons. Over time, the margin of the crown may begin to show and become unsightly. In addition, as time passes, the color of the surrounding teeth may change due to either bleaching or natural darkening. Generally crowns are very predictable and last longer than a large filling would.