Cochrane Summaries

Trusted evidence. Informed decisions. Better health.

Fluoride varnishes for preventing dental caries in children and adolescents

Marinho VCC, Worthington HV, Walsh T, Clarkson JE
Published Online: 
11 July 2013

Review question

The main question addressed by this review is how effective the use of fluoride varnish for the prevention of caries in children and adolescents is compared to placebo (a treatment without the active ingredient i.e. fluoride) or no treatment.


Tooth decay (dental caries) is a significant health problem worldwide. It affects not only the vast majority of adults but also children, from 60% to 90% of them. In other words, six to nine children in every 10 are affected by tooth decay. Levels of tooth decay vary both between and within different countries, but it is generally true that children in lower socio-economic groups (measured by income, education and employment) have greater levels of tooth decay. Untreated tooth decay causes progressive destruction of the tops of teeth (crowns) and this is often accompanied by severe pain and suffering. Repairing and replacing decayed teeth is extremely costly in terms of time and money and is a major drain on the resources of healthcare systems.

The prevention of dental caries in children and adolescents is regarded as a priority for dental services and considered more cost-effective than its treatment. Fluoride is a mineral that prevents tooth decay. Fluoride is added to the water supply in many areas. It can also be applied directly to teeth in the form of fluoride varnish. This is applied to first (baby) and permanent teeth (depending on the age of the child) usually by a dental professional from two to four times a year. Because it stays on the surface of the tooth for relatively long periods of time it releases fluoride in an efficient and effective way.

Study characteristics

This review of existing studies was carried out by the Cochrane Oral Health Group and the evidence is current up to 13 May 2013.
In this updated review there are now 22 trials published between 1975 and 2012 in which a total of 12,455 children were randomised to treatment with either fluoride varnish or placebo/no treatment. Study duration ranged from one to five years among included trials (12 of these lasted two years).

Key results

The evidence produced has been found to be of moderate quality due to issues with trial designs. However in the 13 trials that looked at children and adolescents with permanent teeth the review found that the young people treated with fluoride varnish experienced on average a 43% reduction in decayed, missing and filled tooth surfaces. In the 10 trials looking at the effect of fluoride varnish on first or baby teeth the evidence suggests a 37% reduction in decayed, missing and filled tooth surfaces. There was little information concerning possible adverse effects or acceptability of treatment.

Quality of the evidence

The evidence presented is of moderate quality due to issues with trial designs.