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When tetracycline was introduced over 60 years ago, people were thrilled to have another alternative antibiotic. While it was bad for bacteria, tetracycline also proved bad for the dentin in children’s teeth, causing a reaction that stained the patient’s teeth grey.

The first case of reported tooth discoloration in children occurred in 1956. Many, many other children had their teeth stained over the following decade before the connection was fully understood.

Teeth whitening can’t change this type of staining, as it is in the dentin of the teeth. Contrary to what you may have heard, teeth whitening doesn’t whiten staining in the dentin. The only way you can do anything about a tooth or teeth that tetracycline has turned grey would be to crown the tooth or to place porcelain veneers on the front side of the stained teeth.

Here’s some more information on tetracycline and staining.

Why did it turn teeth grey?

Tetracycline staining is tied to tooth mineralization. In teeth, mineralization is an ongoing process, where teeth continually lose (demineralization) and gain (remineralization) minerals such as calcium. When teeth lose more minerals than they regain, that is when decay sets in. Mineralization is especially active in young, growing teeth. Ingested fluoride has been proven to help in this process by strengthening the developing permanent teeth from within. Fluoride applied directly to the teeth helps to speed remineralization on the tooth surface.

Once it started showing discoloration, research looked into what tetracycline was doing to teeth. It showed that if the teeth were exposed to tetracycline at a time of tooth mineralization or calcification, the tetracycline bound to the calcium ions in the teeth. If this happens before the teeth erupt, the tetracycline that has bound to the calcium will cause the teeth to come out with an initial fluorescent yellow discoloration. Once these teeth are exposed to light, however, the tetracycline will oxidize, and the discoloration will change from fluorescent yellow to non-fluorescent brown or grey over a period of a few months to years.

The location of the discoloration will correspond directly to the stage of tooth development at the time of the tetracycline exposure. Permanent teeth tend to show the discoloration with less color, but it is more widespread across the tooth.

Tetracycline is limited in its timeframe for use

Once the link and timeframe were established, the FDA changed the rules on the use of tetracycline. Now the antibiotic is not to be used by doctors during the second and third trimesters of pregnancy or in children up to 8 years of age. These ranges are the periods of calcification of the teeth.

If you have a tooth or a few teeth that tetracycline turned grey, during your next checkup and cleaning with us, we can talk about solutions. Call Dr. Egger at (989) 773-3560 to make an appointment.