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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

Fluoride varnish and fissure sealant are equally good at preventing tooth decay on children’s first permanent back teeth when applied to six or seven year olds in South Wales. Six applications of fluoride varnish were less expensive, by about £68 per child, for the NHS at 36 months compared to applying the more expensive fissure sealant.

Children’s permanent back teeth are particularly vulnerable to decay when they first come through. The pitted biting surface can make these teeth difficult to keep clean to prevent decay.

This NIHR-funded trial looked at two interventions to prevent decay: fluoride varnish applied six times every six months at school and a syntheticresin, protective polymer coating, applied once and replaced if needed.

This large, UK-based trial supports NICE recommendations to apply fluoride varnish to children’s teeth as part of a school-based community dental programme in areas of high need with children at risk.

Why was this study needed?

The NHS spends £30 million per year removing decayed teeth in children and there is a strong link between socioeconomic status and rates of decay.

Children’s first teeth start coming through around six months, these “baby teeth” are then replaced by permanent teeth. Around six years old children’s back teeth, the first permanent molars, come through. These do not replace baby teeth. Maintaining good dental hygiene and regular brushing with fluoride toothpaste is important in preventing decay and prolonging the life of teeth.

Poor oral health can have a big impact on people’s lives as it leads to pain, tooth loss, affects daily tasks such as eating and speaking, and can reduce people’s confidence in social situations. Children from socially and economically deprived backgrounds are at increased risk, so this study looked at two different methods to protect the first permanent molars from decay in an area where children were at high risk.

What did this study do?

This randomised controlled trial included 1,015 children aged six and seven years old. In addition to their usual toothbrushing, children either had a fluoride-rich varnish applied to their first permanent molar teeth or a hard resin fissure sealant applied to provide a protective layer.

The varnish was reapplied at six, 12, 18, 24 and 30 months. Fissure sealant was checked every six months and repaired if damaged. The intervention was delivered by a community dental service in an area of high socioeconomic deprivation in South Wales.

The health professionals assessing the children’s teeth for decay were not informed of which treatment they had received, but fissure sealant is visible on the teeth so they may have been aware of the treatments that each child had received. The trial included sufficient numbers of children for us to feel confident in its findings and 82% of the children were assessed at 36 months.

What did it find?

  • There was no difference in the proportion of first permanent molar teeth that developed decay (7.5%) in both the varnish and fissure sealant groups.
  • The pitted, biting surfaces of teeth were more likely to develop decay than smooth surfaces (6.4% compared to 1.1%) after 36 months. There was no significant difference between the varnish and fissure sealant.
  • Overall fluoride varnish was cheaper to use than fissure sealant (£432 compared to £500) and created a significant cost saving for the NHS of £68.13 (95% confidence interval [CI], £5.63 to £130.63) per child compared to fissure sealant at 36 months.
  • Children were asked to indicate how happy they were at the start and end of the trial, using a visual scale of faces showing different emotions or feelings. The children in the fluoride varnish group were significantly more likely than the fissure sealant group to say they were happy at the start of the trial, but were significantly less likely to report being happy at the end of the trial. Most of the children completed the trial, which suggests that the treatment was generally acceptable.

What does current guidance say on this issue?

NICE 2014 guidelines recommend that local authorities undertake a needs assessment to identify areas where children are at a high risk of poor oral health. In these areas NICE recommends that authority’s commission supervised tooth brushing schemes in nurseries and primary schools.

Where a tooth brushing scheme is not feasible, NICE recommends a community-based programme of applying fluoride varnish at least twice a year in primary schools. Ideally – where resources permit – NICE recommends commissioning both tooth brushing and fluoride varnish programmes.

What are the implications?

Fluoride varnish and fissure sealant were similarly effective in preventing tooth decay in six and seven year old children’s first permanent teeth. These interventions were effective amongst children with high social and economic deprivation, who are particularly at risk of tooth decay.

Fluoride varnish was cheaper than fissure sealant and saved the NHS more money. Although the children were less happy with the varnish than the fissure sealant, most continued to the end of the trial, suggesting that the treatment was acceptable even if not entirely pleasant.

The findings of this trial support NICE recommendations to use fluoride varnish as part of a school-based community dental programme in areas of high need.


Citation and Funding

Chestnutt IG, Hutchings S, Playle R, et al. Seal or Varnish? A randomised controlled trial to determine the relative cost and effectiveness of pit and fissure sealant and fluoride varnish in preventing dental decay. Health Technol Assess. 2017;21(21):1-256.

This project was funded by the National Institute for Health Research Health Technology Assessment (project number 08/104/04).



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NICE. Oral health: local authorities and partners. PH55. London: National Institute for Health and Care Excellence; 2014.

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Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


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