Fluoride varnish as a public health measure to reduce caries

A cluster randomised controlled trial (RCT) was carried out.

Twice-yearly applications of fluoride varnish were made in a test group of children from relatively deprived areas, with a similar no-intervention control group. The test and control children were from two school years (aged 6-8 years) from 24 state primary schools in the Manchester area. Fluoride varnish was applied five times at school over a period of 26 months by dental hygienists.

Caries increment indicated by decayed, missing or filled teeth in the primary (dmft) or permanent dentition (DMFT)was measured.

A total of 2091 children in 24 schools were eligible for inclusion in the study. No response was received from 1023 children, 154 did not consent and 914 gave positive consent. Of those giving positive consent, 457 were randomly allocated to the test group and 457 to the control group. During the study, 263 children in the test group received five varnish applications and 319 received four or more applications. At baseline there were no important differences in caries levels of participants in the test and control groups. At the final examination there was only one statistically significant difference in the caries increment, for small enamel lesions only in the primary dentition, with the test children having fewer lesions. This was not, however, apparent for the other levels of caries diagnosis, nor for all three levels of caries diagnosis in the permanent dentition.

The results of this study suggest that the use of this type of fluoride varnish intervention cannot be recommended as a public health measure for reducing caries in this population.