A “crown” or a “cap” is the term used to restore a decayed or broken tooth that needs to be completely encased to protect the tooth beneath it. A crown's dual purpose is to restore the tooth's form and function. Decades ago gold was the material of choice for a crown. What we ultimately choose depends on a particular crown's requirements with regard to the tooth's appearance and function, and to some extent what you want.
Gold: Gold crowns last the longest and wear the best (at about the same rate as natural teeth), but they are not used as frequently today, especially if they are visible in a person's smile. Gold crowns are made of cast gold, a technique that has been in use for over a hundred years. They can last for decades, and have been known to last 50 years or more. They tend to cost less per tooth than porcelain or other materials.
All-Porcelain: “All porcelain” crowns have a natural appearance and as technology improves they are gaining popularity. Dental porcelains are composed of ceramic substances that are variations of glass. This gives them their translucent, lifelike appearance — but it makes them brittle and subject to fracture. Therefore all-porcelain crowns may not be a good choice for back teeth because they frequently fail under the biting forces applied during chewing and especially adverse habits like tooth clenching or grinding. Porcelain crowns are made of material that doesn't wear. Consequently, it can cause excessive wear to the teeth they bite against.
Porcelain-Fused-to-Metal (PFM): PFM crowns have been in use for more than 40 years. They combine a substructure of gold or platinum for strength and have porcelain “facings” for the visible surfaces. In some ways they combine the best of both worlds, but they do have some problems; the metal can show through the porcelain, detracting from its life-like appearance. These crowns can have a functional lifespan of about 20 years or more.
New and Future Materials: Newer “pressed-ceramic” restorations and computer-milled ceramics have received good reviews for aesthetics and service. These new materials are being intensively researched. Initial results look good, but we'll have to see how they last over time.
Contact us today to schedule an appointment or to discuss your questions about crowns and other dental restorations. You can also learn more by reading the Dear Doctor magazine article “Gold or Porcelain Crowns?”