Sealants or fluoride varnishes: which treatment is better for preventing decay in the permanent back teeth of children and adolescents?

Tooth decay is when a small hole develops in a tooth. This happens because bacteria that live in the mouth feed on sugar in the food we eat. As they feed, the bacteria produce acid that attacks teeth. If teeth are not cleaned regularly after eating, or if someone consumes a lot of sugary foods and drinks, the repeated acid attacks can create holes in the hard outer surface of the teeth. If untreated, these holes can deepen and damage the layer of tooth underneath the surface (dentine). Many people around the world develop tooth decay at some point in their life. In most adolescents and children over the age of six years, decay damages the biting surfaces of the permanent teeth at the back of the mouth.

To prevent decay, dentists can apply a dental sealant, or fluoride varnish, directly onto the back teeth. A dental sealant is a coating made from an adhesive material such as resin or glass ionomer, which the dentists applies once to teeth. It seals off the grooves in teeth that tend to collect food, and protects them from the acid. By comparison, a fluoride varnish is a sticky paste that contains high levels of fluoride; fluoride is a mineral naturally present in teeth that protects them from damage. Fluoride varnishes need to be applied to teeth by the dentist two to four times a year.

What was the research?

A systematic review of the evidence to find out whether dental sealants (or sealants together with fluoride varnishes) or fluoride varnishes are more effective for reducing tooth decay on biting surfaces of permanent back teeth in young people

Who conducted the research?

The research was conducted by a team led by Wafa Kashbour from the University of Manchester, UK, on behalf of Cochrane Oral Health. Puneet Gupta, Helen V. Worthington and Dwayne Boyers were also on the team.

What evidence was included in the review?

We looked at the data from 11 randomised controlled trials. A total of 3,374 children aged 5 to 10 years participated in the trials, and were randomly assigned to receive dental sealant (or sealant together with fluoride varnish) or fluoride varnish alone. The evidence is current as of March 2020.

What did the evidence say?

When we combined four studies that compared resin sealants versus fluoride varnish, we found that neither intervention worked better than the other.

The three individual studies that compared sealants made from glass ionomer versus fluoride varnish could not be combined and had mixed results.

One small study found that using both sealants and fluoride varnish may work better than using fluoride varnish alone.

Five studies reported that no side effects were associated with the use of either sealants or fluoride varnishes. The other studies did not mention whether or not any side effects occurred.

How good was the evidence?

The evidence was of very low certainty so we are not able to be confident in the findings.

What are the implications for dentists and the general public?

At present, we do not know whether it is better to apply sealants or fluoride varnish to prevent tooth decay in children’s back teeth. We do know that both interventions are effective for reducing tooth decay, and current evidence does not suggest that one works better than the other.

Fourteen studies are currently underway. Their findings could improve the evidence in future versions of this review.

What should researchers look at in the future?

More high‐quality research is needed to compare the relative effectiveness of sealants versus fluoride varnishes for preventing dental decay on biting surfaces in back teeth.


Kashbour  W, Gupta  P, Worthington  HV, Boyers  D. Pit and fissure sealants versus fluoride varnishes for preventing dental decay in the permanent teeth of children and adolescents. Cochrane Database of Systematic Reviews 2020, Issue 11. Art. No.: CD003067. DOI: 10.1002/14651858.CD003067.pub5.

This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Group Editorial Base.

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