Effectiveness of bi-annual fluoride varnish application in the control of dental caries in preschool children: results after 12 months of follow-up

The aims of this study were to evaluate whether the application of fluoride varnish in preschool children at six-month intervals reduces the number of children with dentin caries and decreases the incidence of enamel and dentinal caries lesions in the primary dentition. We also sought to assess whether this intervention is inversely associated with the occurrence of tooth abscess and dental pain and to describe any possible side effects. The study population comprised 200 children, 12 to 48 months of age. They were enlisted in a public health center in the city of Rio de Janeiro and were randomly assigned to the test group (Duraphat® fluoride varnish) or the control group (placebo varnish). To record caries incidences, the children were examined at the baseline and every six months, during the period of one year, by two trained and calibrated pediatric dentists (Kappa=0.85). The presence of pain, abscess and side effects were recorded through interviews with the children’s caregivers. The children, their caregivers, the operators and the examiners did not know which group each child belonged. At the end of the follow-up period, 71 children of test group and 77 of the control group were analyzed. We found that 13 children in the test group and 20 children in the control group presented new dentinal caries lesions (Chi-square test, p= 0.34) and that the mean caries increment at the dentin level was 1.1(dp= 3.4) and 1.4 (dp=2.8) in the test and the control groups respectively (Mann-Whitney test, p=0,29). One child reported dental pain and tooth abscess, and two other children reported only dental pain. All three children belonged to the test group. One child reported a burning sensation in the mouth following application of the placebo varnish and one parent of a child in the test group felt upset about the yellowish discoloration of the child’s teeth after the application of the fluoride varnish. We concluded that the six-monthly application of fluoride varnish in preschool children is safe and appears to contribute to the control of caries progression. However, a longer follow-up period is necessary before conclusive evidence can be drawn regarding the effectiveness of this intervention. We did not find an association between the occurrence of tooth abscess and dental pain, and the professional use of fluoride varnish.