There are a few potential causes for why a tooth might be darker than the others.
It sometimes occurs that you may have an enamel defect in that tooth. Most of the time, this won’t make your tooth turn dark: your tooth will have always been dark. But sometimes there’s a defect that may cause one tooth to stain more than your other teeth.
Tooth Decay and Infection
A cavity can cause the tooth to darken. You may not see the cavity on the surface: it could have a small hole at the top, but much more decay underneath. This is why we use DIAGNOdent, a laser cavity detection system that can find tooth decay hiding under the surface.
If a tooth develops a significant amount of decay, it can become infected. Oral bacteria invade the center of a tooth, killing the nerve and filling the tooth with bacteria. This can cause the tooth to become dark in color.
Metal Amalgam Fillings
Sometimes the cure is almost as bad as the disease, and that’s the case for metal amalgam fillings. They can be used to fill in a cavity, but the silver metal can turn dark as it oxidizes. Sometimes, the filling can even make the entire tooth turn dark in color.
Another common cause of tooth discoloration occurs when your tooth gets struck. The tooth may initially seem fine, but, slowly, it turns darker in color than your other teeth. The tooth nerve may have died inside.
How to Fix a Discolored Tooth
If a single tooth has become discolored, we have a couple of options. In some cases, we can try tooth bleaching on the discolored tooth. This is an unreliable and unpredictable treatment option.
A more reliable approach is using porcelain veneers to cover the discolored tooth. This can give consistent, attractive results.
Sometimes, in the case of tooth decay, trauma, or large metal amalgam filling, we might recommend root canal treatment and a porcelain crown instead of a veneer. Which treatment is best for you depends on the exact condition of your teeth.