Betsy Miller
Dental sealants are clear or tinted plastic coatings that are painted onto the chewing surface of the back teeth (the molars and bicuspids). The sealant protects the surface of the tooth from plaque, which can cause tooth decay. Brushing and flossing are still needed to prevent cavities in other areas and to keep the gums healthy.
Sealants are used because the back teeth have irregular surfaces that contain pits and grooves, also called fissures. Fissures occur naturally and are so small that a toothbrush bristle cannot fit into them. This makes it impossible to completely remove plaque and bits of food when brushing. Because of this, people may develop cavities in these areas, even if they have no other cavities.
The overall rate of cavities in American children's permanent teeth has been declining. However most of this decline has been in the smooth portions of teeth. The rate of cavities in the chewing surfaces of the back teeth has not decreased as quickly. Because of this, pit and fissure cavities make up a greater proportion of cavities today.
Who Benefits From Sealants?
The American Dental Association recommends sealants for all children, even those who receive fluoride treatments or drink fluoridated water. Fluoride is most effective on the smooth surfaces of the teeth, and least effective in pits and fissures.
Sealants may be used on baby teeth if the dentist recommends it. More commonly, they are used on six-year molars and twelve-year molars. Sealants may be applied shortly after these teeth come through the gum, or to other permanent teeth during childhood through adolescence, or even in adulthood.
Your dentist will assess your child's risk for decay and develop an individual treatment plan, which may include sealants. The dentist will take into consideration whether your child's teeth have deep fissures that make them difficult to clean. Children with deep fissures or who have a tendency toward tooth decay may be in greater need of sealants.
Sealants can be used on teeth without decay that are at risk for cavities, teeth with enamel cavities, or questionable teeth that may have enamel cavities. An enamel cavity has decay only in the enamel layer of the tooth. Fissures are so small that the dentist may not be able to tell with absolute certainty whether the tooth has a small cavity. Traditionally dentists used instruments to check pits and fissures for cavities. This method was found to give a high rate of false positive results ‚ teeth that some dentists thought had cavities, actually did not. For this reason, dentists are less likely to use instruments when assessing pits and fissures today.
The dentist will wait until a child's molar is completely through the gum so that the tooth can be kept dry when the sealant is applied. The child must also be able to tolerate having the sealant applied. From that point on, sealants can be applied in childhood, adolescence and even adulthood if the tooth would benefit from this treatment.
How Is A Sealant Applied?
Sealants may be applied by dentists, or by hygienists or dental assistants supervised by a dentist.
1. The tooth is cleaned and dried. Cotton is placed around the tooth so that it will stay dry.
2. The dentist puts a solution onto the chewing surface of the tooth for 10-30 seconds. This solution slightly roughens it to help the sealant to stick to the tooth. If some of this solution gets on another part of the tooth, or a different tooth, it will do no harm.
3. The dentist removes the cotton, then rinses and dries the tooth. Fresh cotton is placed around the tooth.
4. The dentist then paints the sealant onto the tooth in a thin film that covers the pits and fissures. Some sealants are cured with ultraviolet (UV) light to harden. Others quickly harden without curing.
Recently, new sealants have been developed that use a solution that does not need to be rinsed. These sealants do not require UV light. The solution is applied for 20 seconds. Air is blown onto the tooth. Then the sealant is applied. It is not necessary to rinse the tooth or to replace the cotton with this method, so it may be easier for young children to tolerate.
Frequently Asked Questions
How Long Does The Sealant Last?
Sealants last for several years. During routine dental examinations the dentist will check to make sure the sealant is still intact. After several years, the dentist may need to reapply sealant.
What If The Dentist Puts A Sealant On A Tooth That Has An Enamel Cavity?
Enamel cavities under sealants stay the same size. They do not continue to grow larger because no plaque, food, or germs can get into the cavity. The dentist will not apply a sealant to a tooth with a deep cavity.
Can The Sealant Be Absorbed? Is It Safe?
Sealants are safe. They have been used since the 1960s. Studies have been done to test the blood of people who have sealants. The results show that the chemicals in sealants cannot be detected in the bloodstream.
When Should Sealants Be Avoided?
Sealants are not recommended for teeth with dentin caries (deep cavities that extend through the enamel of the tooth and into the dentin). Sealants are also not recommended if the tooth is not far enough through the gum to be kept dry; if the tooth has a filling, or in a baby tooth that is expected to fall out in a short time.
Betsy Miller is a freelance technical writer and editor. She lives in the San Francisco Bay Area with her husband and two children.
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