People often assume that once they have a porcelain crown placed on a tooth, it will last the rest of their lives. Although dental porcelain crowns may last for a very long time, it is not correct to say that they will last forever.
This is one of the most difficult questions asked of a dentist because, in essence, no one can be sure. However, there are a few resources available that can give us an idea of how long your porcelain crowns may last.
One resource is insurance companies. Even though the insurance company should not dictate the type of treatment that should be done, they give some insight into the matter. Insurance companies will pay for a new porcelain crown on the same tooth after five years. So, in essence, they believe that dental crowns will last at least five years. Another resource available is the dental literature. The dental research has some extreme variability in this area. It provides information that ranges from a 20% failure rate in 3 years all the way to a 3% failure rate in 23 years. So, which is correct? The answer actually has to be looked at on a case-by-case basis. To do this, we need to look at why dental crowns have to be replaced.
There are many reasons why dental crowns need to be redone. Fracture is one example. The fracture incidence of dental crowns can be related to either the type of restoration (gold, metal ceramic, all-ceramic) or where the restoration is placed in the mouth (anterior vs. posterior). Another risk factor is if a person has a grinding habit at night. A crown will have a higher risk of fracture in a mouth that applies more forces to the teeth by grinding than in one that does not have any incidence of grinding.
Decay can be another reason why dental crowns need to be replaced. Just because a tooth receives a crown does not mean it is less prone to decay. In fact, because it has more areas that may trap plaque, it needs to be cleaned as well, if not more meticulously, during home care.
Esthetics can be another reason why dental crowns are replaced. Esthetics is one of the main reasons people choose to have a new crown made in the anterior part of the mouth. This occurs because as we get older, our teeth will change color and progressively get darker while the tooth with the crown will stay the same color as the day it was placed. A discrepancy between the color of the teeth will become more evident over time. In addition to color, esthetic changes in the position of the gum tissue over time can also affect the look of the crown.
Which one of these areas may be a factor in a patient's mouth is uncertain. An idea can be obtained by evaluating the reason a crown was needed in the first place (such as a fractured tooth, decay, etc.). In conclusion, it is unclear how long dental crowns will last. Their life span may be anywhere from a few years all the way to 20 years and beyond. A lot of it will depend on the need for the crown in the first place and how well the mouth is taken care of after the crown is placed.
By Greggory Kinzer, DDS, MSD