Fluoride Varnish and Fissure Sealants: Does My Kid Need These?

by ParentCo. June 21, 2017

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A friend mentioned in a recent chat that her son had fissure sealants placed on his four first permanent molars and now feels relieved that he won’t get dental cavities on these adult teeth. Another mum responded that her daughter had fissure sealants on her molars and within three months all the fissure sealants needed “topping up” because her daughter grinds her teeth in her sleep. I was asked if I placed fissure sealants on my daughter’s molar teeth, to which I replied, “Katelyn’s molars have not been fissure-sealed. She does get fluoride varnish two to three times a year though.” That led to an interesting discussion regarding what is preferable for prevention of dental cavities in children: fissure sealants or fluoride varnish? And are these really necessary?

What does current scientific evidence say?

We immediately dived into our mobile phones for current research papers, updates, and recommendations. Here are the key findings from our impromptu journal club: Conclusions from the respected Cochrane systematic review, published in 2016, suggest that there are only a limited number of good quality studies available, and analysis of these indicate that fissure sealants may be slightly superior to fluoride varnish when it comes to preventing dental cavities. However, the evidence is of such a low quality that clear conclusions cannot be drawn. Results of a large Cardiff University study comparing fluoride varnish and fissure sealants in eight hundred high dental decay risk children in the UK, published in March 2017 in the Journal of Dental Research, concluded that semi-annual applications of fluoride varnish is just as protective against dental cavities as fissure sealants.

What are fissure sealants?

Fissure sealants are thin layers of adhesive materials placed over the biting (occlusal) surfaces of primary or permanent molar teeth to physically cover the hard to reach deep pits and grooves of teeth where bacteria and food debris may accumulate and result in dental decay. A Cochrane systematic review published in 2013 looked at the benefit of fissure sealants alone for prevention and control of dental decay and concluded that fissure sealants are primarily beneficial for children with high dental decay risks. A combined American Dental Association and American Academy of Pediatric Dentistry report on fissure sealants also supported the benefit of fissure sealants for preventing and arresting dental decay on biting surfaces, not only in adult molar teeth but also baby molar teeth.


  • Fissure sealants provide physical protection that stays on the tooth and does not dissolve quickly.
  • Fissure sealants prevent bacteria and food debris from hiding in the bottom of pits and grooves of molars where the toothbrush can’t reach.
  • Fissure sealants are useful for arresting early enamel decay on the biting surfaces of molar teeth and for preventing decay from starting.


  • Fissure sealants are placed on the biting surfaces of teeth and protect these surfaces only.
  • Fissure sealants may break off or wear over time, so regular repairs are critical.
  • Placement of fissure sealants require more cooperation from children than fluoride varnish.
  • Fissure sealants cost more than fluoride varnish.
  • For children with little risk of dental decay (i.e. no cavities, restorations, or visible dental plaque on teeth, and excellent oral hygiene and diet), fissure sealant placement may be perceived as unnecessary or over-servicing.

What is fluoride varnish?

Fluoride varnish is a fluoride-containing agent that is applied or painted onto teeth for prevention of dental decay. Fluoride varnish is formulated especially to stick onto the teeth surfaces to enable remineralization by fluoride ions over time. According to the American Academy of Pediatric Dentistry and American Academy of Pediatrics, children as young as six months of age can benefit from semi-annual applications of fluoride varnish. Originally, fluoride varnish only contained sodium fluoride. In recent times, calcium- and phosphate-containing fluoride varnishes have been marketed as having superior decay prevention and remineralization benefits. However, a recent laboratory study published in the International Journal of Paediatric Dentistry in May 2017 suggested that the original sodium fluoride which only containing varnish was superior for remineralization of enamel decay.


  • Fluoride varnish is able to reverse early tooth demineralization and remineralize tooth structures.
  • Fluoride varnish can be applied to all surfaces of teeth and so exert benefits that are not limited to just pits and fissures.
  • Fluoride varnish requires less cooperation from children and is easier to apply than fissure sealants.
  • Fluoride varnish costs less than fissure sealants.


  • Effectiveness of fluoride varnish depends on multiple applications per year.
  • Fluoride varnish may not penetrate into the deep pits and grooves of at-risk teeth easily.

The verdict?

The consensus we came to from available evidence was that both fissure sealants and fluoride varnish are useful. Whether one is preferable over the other will vary from person to person and depend on various factors including level of dental decay risk, depth of molar pits and grooves, age, habits, and lifestyles.



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