Effectiveness of fluoride varnish for children under three years
Fluoride varnish for children under three years probably reduces caries in milk teeth.
- Issued/Revised: 2015
In Norway three year olds gets their first free dental examination at the public dental health centre. This public dental health service is free of charge until the child turns 18. By two years of age, children are examined at the children’s public health centre (helsestasjon) and referred to public dental service when needed.
We have summarized results from nine randomized controlled trials on the effect of fluoride varnish for children up to three years.
The available documentation shows that:
- Fluoride varnish probably reduced caries in milk teeth.
- Fluoride varnish may have few or no side effects or other adverse events.
We have no information about infections or poisoning.
A Norwegian study from 2013 revealed that 13 percent of all three year olds had caries in their milk teeth’s. However, the prevalence of caries varies; many children have little or no caries, whereas some children develops more and earlier caries. Probably, preschoolers who develops caries have increased risk of developing more caries on permanent teeth’s during the school years.
In Norway three year olds get their first free dental examination at the public dental health center. This public dental health service is free of charge until the child turns 18. Children at two years of age are examined at the children’s public health center and referred to public dental service when needed. We do not know how many children are referred.
The Norwegian Directorate commissioned this systematic review. The results will be used in the development of a new evidence-based guideline for children’s public dental treatment.
We identified one systematic review about fluoride varnish for children under 16 years. The review was published by the Cochrane Collaboration and the literature search was updated in May 2013. To identify more resent trials we contacted the authors of the Cochrane-review. We also performed a systematic literature search to find new randomized controlled trials about the effects of fluoride varnish for children under three years. We searched the following databases: MEDLINE, PubMed, Embase, Cochrane CENTRAL and IS Web of Science. We searched for ongoing trials registered in the WHO International Clinical Trials Registry, without language restrictions. We read the reference list from the Cochrane-review, other overviews and guidelines to find relevant trials.
Two researchers assessed all titles and abstract independently according to the predefined inclusion criteria. All possibly relevant trials were read in full text by two researchers. Risk of bias for all trials was assessed for the new trials, whereas the risk of bias assessment from the Cochrane-review was used for the trials included there. We graded the documentation in accordance with guidance with the Cochrane -handbook.
The search for trials was conducted in June 2015. We included nine randomized controlled trials. All studies except one had two years follow-up.
Six trials reported prevented caries in surfaces of milk teeth (dmfs). The intervention groups received either fluoride varnish, fluoride varnish and counselling or a health program in addition to fluoride varnish. A meta-analysis of the six trials with 2500 children revealed that fluoride varnish prevents caries in surfaces of milk teeth with a Prevented fractions of 0.38 (0.27 – 0.49). This means 38 % fewer surfaces with caries in the fluoride varnish group. Moderate quality (⊕⊕⊕⊝).
Meta-analysis of three trials with 443 children revealed that fluoride varnish prevents caries in milk teeth (dmft) with a Prevented fractions of 0.72 (0.51 – 0.94). This means 72 % fewer teeth with caries in the fluoride varnish group. Moderate quality (⊕⊕⊕⊝).
Five trials reported on the risk of developing new caries in milk teeth. The intervention groups received either fluoride varnish or fluoride varnish and counselling. The meta-analysis of five trials with 1127 children revealed a risk reduction of new caries risk ratio: 0.75 (0.55 – 1.01)). Low quality (⊕⊕⊝⊝).
We do not know if fluoride varnish leads to infections or poisoning because none of the studies reported this outcome. Six trials with 2 738 children reported side effects or other adverse events. One case was reported in the placebo-group and two cases of in the fluoride varnish group. Thus, we conclude that fluoride varnish seems to have few or no side effects or other adverse events. Low quality (⊕⊕⊝⊝).
Fluoride varnish for children under three years probably reduces caries in milk teeth. None of the trails were performed in Norway, but one was performed in Sweden in the 1970’s. Fluoride varnish was used much the same way across studies. We assume no difference in effect for Norwegian children.
Our conclusion is in line with that of the authors of the Cochrane-review who concluded that fluoride varnish two to four times a year leads to a reduction of caries in both milk teeth and permanent teeth. There is a risk that relevant studies were lost in our systematic search, but we find it unlikely that any potential missing trials would have substantially changed our conclusion.
Fluoride varnish for children under three years probably reduce caries in milk teeth.