By Courtney H. Chinn, D.D.S., M.P.H.
Columbia University College of Dental Medicine

You may have heard the term "sealants" before at your dentist's office. Perhaps your dentist has even recommended them for you or your child.

While sealants offer an effective way to prevent cavities, there has been some question as to which patients and which teeth could benefit most from them. Expert guidelines based on the latest research have recently come out. They offer helpful advice on the best use of sealants for both children and adults.

Getting dental sealants is a common procedure. It's simple, quick and painless. First, the chewing surfaces of a tooth found to be at risk for dental decay are thoroughly washed and dried. Then, a thin liquid coating of plastic is painted into the deep grooves and crevices of the tooth surface. This coating is hardened into place, "sealing" the tooth from any future food, debris or bacteria that might enter and cause decay.

Dental sealants are not a perfect "cure-all" for future cavities, but they are still a highly effective way of protecting teeth. This is especially true with the new permanent molars of young children. These teeth are often at high risk for decay when they first appear in the mouth. The American Academy of Pediatric Dentistry (AAPD) encourages dental sealants for both baby and adult teeth that tend to collect a lot of plaque or have a high risk of developing a cavity.

Discussion in the dental community about the most appropriate use of sealants has centered on two questions:

1. Which teeth should have sealants placed as a preventive measure?
2. Does placing a sealant on a tooth with some early decay cause the decay to get worse?

In February 2008, the U.S. Centers for Disease Control and Prevention (CDC) published findings from a work group that had examined current research on sealants. Their main goal was to update the dental community on how well sealants prevent cavities in the permanent teeth of adults and young children. The group also recommended guidelines.

In March 2008, the American Dental Association (ADA) also published recommendations for the use of sealants . Both groups addressed the two common questions about sealants very well.

Which teeth should be sealed to prevent cavities?

If sealants are so helpful, shouldn't everyone get sealants on all their teeth? Not necessarily. The ADA supports sealant placement only on those teeth that are found to have a high risk of future cavities.

If a dentist finds that you or your child is at high risk of tooth decay, sealants on the chewing surface of permanent teeth may be recommended. In some cases, they may be used even on baby teeth. However, if either you or your child is found to be at low risk of dental disease, the benefit of sealants may be minimal and not always recommended.

The "take home message": Ask your dentist about your child's risk, as well as your own risk, for tooth decay. Sealants may be recommended.

Is it all right to place a sealant over a tooth with decay?

This has been a tough issue for dentists. In the past, it has been thought that sealing a tooth with signs of decay might cause a cavity to get bigger undetected beneath the sealant. However, both the CDC and the ADA recommend placing sealants on teeth with "early signs of tooth decay." This means that the decay process has started, but has not yet made a hole in the tooth.

We need to be a little careful about what we call "early tooth decay." A tooth with an obvious cavity definitely ought to get a filling, not a sealant. However, research has found that sealants placed on teeth that are just beginning to decay can help to keep the process from getting worse. Sealants also can lower the number of cavity-causing bacteria on the tooth surface.

The "take home message": Be sure both you and your child see the dentist regularly. Discovered early enough, tooth decay can be stopped using sealants and other preventive treatment.

Courtney H. Chinn, D.D.S., M.P.H., is an assistant professor at the Columbia University College of Dental Medicine. As a pediatric dentist, Dr. Chinn has provided care for young children in a variety of dental settings, including mobile dental vans, community health centers and school-based clinics. Dr. Chinn also has served children with special needs, children with chronic illnesses and other unique child populations. He is working with local Head Start centers to improve the oral health of young children, from birth to age 5, and their families in the Washington Heights community in Northern Manhattan.