17250 N. 43rd Ave #3
Glendale, AZ 85308
Peterson, Jonathan R D.D.S.
2220 W Southern Ave # 102
Mesa, AZ, 85202-4706
Valley Endodontics Specialty
20100 N 51st Ave # C310
Glendale, AZ, 85308-5000
Johnson, Randall J D.D.S.
7600 E Camelback Rd # 4
Scottsdale, AZ, 85251-2106
Van Der Werf Endodontics
1630 S Stapley Dr # 208
Mesa, AZ, 85204-6659
We have all seen smiles that you know have dental crowns in the front. You look at them and say to yourself that something is not natural. Many times, it is the dark rim of gum tissue that gives it away. The dark rim of gum tissue does not occur around natural teeth, only around teeth that have been covered with dental crowns.
The dark line is associated with an old porcelain dental crown. This style of dental crown is referred to as porcelain fused-to-metal dental crowns because it uses tooth-colored porcelain on the outside and it uses metal under the porcelain for strength. The dark line originates from the edge of the dental crowns where the porcelain and the metal meet at a knife-edge at the gum line. At the knife-edge, a very thin amount of the metal always shows. One of the illusionary techniques cosmetic dentists have used was to hide the thin dark line under the gum line. Over time, the gum tissue would recede and expose the dark line. In some patients the dark line would show through the gum and make it appear dark as well.
The only way to eliminate the esthetic problem is to replace the dental crowns. When replacing just one single dental crown in the front, you should expect that it might take more than one try-in of the new dental crown before it is permanently cemented into place. Because your central incisors are the most prominent teeth in the mouth, matching them is the most difficult esthetic challenge. Only the best dental technicians are able to mimic one central incisor tooth next to another.
Some of the clever ways dentists and dental technicians have been able to mimic natural teeth is through the new advancements in dental materials. New all-tooth-colored ceramic dental crowns are the latest technological advancement cosmetic dentists have to recreate natural teeth. In comparison to porcelain fused-to-metal dental crowns, all-ceramic dental crowns do not contain any metal, thus no dark line can appear.
Some advantages and disadvantages of all-ceramic dental crowns are as follows:
Dental crowns often need to be replaced after several years of service for esthetic or functional reasons. With the growing esthetic awareness of patients and the available ceramic technology, this type of re-treatment is becoming more common in the dental office.
By Benjamin O. Watkins, III, DDS
People often assume that once they have a crown placed on a tooth, it will last the rest of their lives. Although dental 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 dental crowns may last.
One resource is insurance companies. Even though the dental 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 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 tooth 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