The most common complaint associated with crowns is that they look "opaque," "lifeless," and "fake" compared to natural teeth. Do you need an expensive dental makeover to solve the problem? No!
The appearance of a crown is affected by many factors, but ultimately, the final result is determined by how the crown reacts with light. Natural teeth have a high degree of translucency, which means a certain amount of light passes through the tooth. The result of this is that the tooth appears to have depth and vitality.
Traditionally, crowns are made of two materials:
Generally, it is this type of crown that can appear opaque. The reason for this is that while porcelain is very translucent and lets light travel easily through it, no light can pass through the underlying metal. In order to prevent the metal color from showing through the porcelain, which would make the crown seem dark or gray, the metal has to be "masked out" with an opaquing material. It is this masking or opaquing that can affect the final appearance, giving rise to the opaque or lifeless look.
The answer is no. One thing that can be done to improve the appearance is to remove the metal margin that goes around the crown. By keeping the metal inside the crown and having porcelain at the junction between the crown and the tooth, the "black line" appearance at the gum line can be eliminated, thereby increasing the translucency in this area. It also is necessary to have an adequate thickness of porcelain over the metal substructure. If the metal that has been masked out is too close to the outer surface of the crown, the appearance of depth is lost. What it mostly comes down to, however, is the skill level and artistry of the technician who is making the crown. When done correctly, porcelain crowns with a metal substructure can give you the best of both worlds without the expense of an extreme makeover. They can be made to exactly match your other teeth while still appearing lifelike, and since there is metal in it, they have increased strength.
Today, there are dental crowns available that do not require a metal substructure and are made of only porcelain. Depending on the specific type, they get their strength either from the bond to the remaining tooth structure or from a dense tooth colored substructure. Since there is no metal, these types of dental crowns allow more light to pass through, which enables them to have more depth and vitality, much like natural teeth. So why isn't this type of crown used all the time? The main reason is that they are not as strong as crowns with a metal substructure. So, if a person grinds their teeth, these crowns have a greater risk of fracture. Another reason why an all-ceramic dental crown cannot be used in all situations is if the underlying tooth structure itself is dark. Very dark teeth are difficult to mask with these types of crowns because of their translucency. In these instances, the dark color may show through the crown. So, for situations where a lot of force will be placed on the teeth (such as grinding habits) or if a tooth is really dark, a well-made porcelain crown with a metal substructure may be a better restoration.
By Greggory Kinzer, DDS, MSD