Oral Health›Dental visits and treatments

Fissure Sealants: Protecting the Grooves in Back Teeth

Fissure sealants are thin coatings painted into the grooves of the back teeth to help keep out food and bacteria. Here is who they are for, how they are put on, how long they last and what the evidence shows.

Updated September 2026·By the OHA editorial team·8 min read·How we write
Key takeaways
  • A fissure sealant is a thin coating painted into the grooves on the chewing surfaces of back teeth, where decay often starts.
  • They are mainly used on children's adult back teeth soon after they come through, at around 6 and again around 12. Guidance on whether every child needs them differs by country.
  • Putting them on is quick and painless, with no injection or drilling.
  • A Cochrane review found moderate-quality evidence that resin sealants reduce decay in children's back teeth.
  • Sealants wear over time, so your dental team should check them at check-ups. They do not replace brushing with fluoride toothpaste.

The grooves and pits on the chewing surfaces of the back teeth are called fissures. healthdirect Australia explains that tooth decay often starts there, and the Better Health Channel (Victoria) says the grooves are so small that toothbrush bristles cannot get in to clean away food and bacteria. A fissure sealant (also called a dental sealant) fills in those grooves. For how decay develops, see tooth decay.

What is a fissure sealant?

The US National Institute of Dental and Craniofacial Research (NIDCR) describes sealants as thin plastic coatings that protect the chewing surfaces of back teeth. The Better Health Channel says they were developed in the 1960s and create a smooth surface that is easier to clean.

The main types are resin (a plastic material) and glass ionomer (a cement that releases fluoride), according to Cochrane and the American Dental Association. The Australian Dental Association says the material is usually white or clear and sometimes contains fluoride.

Who are they for?

The main use is on the permanent (adult) molars, the large back teeth, soon after they come through:

  • The NHS says sealants can be applied when the adult back teeth come through, usually at about 6 or 7, and again between 11 and 14.
  • The Better Health Channel says the first permanent molars come through at about 6 or 7 and the second molars at about 11 or 12, and that these teeth benefit most.
  • The NIDCR says first molars appear at about 6 and second molars at about 12, and that the sooner sealants go on, the less chance of decay.

Where the countries differ is whether every child needs them.

UK

The NHS says to ask your dentist about fissure sealing. Delivering Better Oral Health, the UK guidance for dental teams issued with NHS England, strongly recommends resin sealants on adult teeth as they come through for children and young people aged 7 to 18 whose dentist is concerned about their risk of decay. It is not listed as a routine step for every child.

Australia

The Australian Dental Association and healthdirect both say not every child needs fissure sealants. healthdirect says they are most often placed in children aged 6 or older and teenagers, usually soon after the teeth appear, and that people with deep grooves or pits may be advised to have them.

United States

The American Dental Association says its scientific council has for years recommended sealants on the baby and adult molars of all children and teenagers. The US Centers for Disease Control and Prevention (CDC) says children of all ages can benefit, that sealants can go on baby or adult teeth from age 2 and throughout adulthood, and that school sealant programmes help reach children at higher risk.

Adults

The American Dental Association (MouthHealthy) says children and adults can benefit, though the earlier the better. The UK and Australian pages we read focus on children and teenagers. Ask your dental team whether sealants would help you.

How are sealants put on?

healthdirect says a dentist, dental hygienist or oral health therapist can place them. The steps it describes are:

  1. Clean and dry the tooth.
  2. Prepare the surface. The American Dental Association (MouthHealthy) says an acidic gel is used briefly to roughen the surface so the sealant bonds, then rinsed off.
  3. Paint the liquid sealant into the grooves.
  4. Harden it with a special light. Some materials set without a light.
  5. Check the bite and polish off any excess.

healthdirect says it does not hurt and no anaesthetic is needed. The Better Health Channel says it takes only a few minutes and needs no injections or drilling. The CDC says your child can eat and drink as usual afterwards.

Sealants can also go over very early decay. The American Dental Association says they can stop early decay that has not yet formed a hole from getting worse.

How long do they last?

Sources give different figures:

  • The NHS says up to 4 years.
  • The Better Health Channel says usually 2 to 7 years, but they may last much longer.
  • The CDC and the American Dental Association say many years or several years.

healthdirect says chewing can wear sealants down, so they sometimes need replacing. Delivering Better Oral Health advises dental teams to check sealants at every visit and re-seal where needed. How well a sealant stays on depends on careful technique, the same guidance says.

Do they work?

The main evidence comes from a 2017 Cochrane review of 38 studies involving 7,924 children and teenagers aged 5 to 16. It found that children aged 5 to 10 who had resin sealants on their back teeth were less likely to get decay in those teeth. As an example, it says that if 40% of back teeth developed decay over 2 years without sealant, sealant would cut this to 6%. Similar benefits were seen up to four years, with less evidence up to nine years. The reviewers rated this evidence as moderate quality, and noted that most of the studies were carried out in the 1970s. Results for glass ionomer sealants were inconclusive.

Delivering Better Oral Health reaches a similar view: moderate-certainty evidence that resin sealants prevent and stop decay for up to 48 months, and inconclusive evidence for glass ionomer.

The CDC says sealants applied soon after the adult molars come in can prevent up to 80% of cavities for 2 years and 50% for up to 4 years. It also says children aged 6 to 11 without sealants are almost three times more likely to have cavities in their molars than children with sealants.

Are they safe?

healthdirect says there are no common risks. In the Cochrane review, four studies looked for problems caused by sealants and none were reported. MouthHealthy says there are no known side effects apart from a possible allergy.

Some parents ask about BPA (bisphenol A, a chemical found in some plastics). The American Dental Association says sealants may release very low levels for a few hours after placement and that, on current evidence, there is no health concern from BPA in any dental material.

Sealants and fluoride varnish

Fluoride varnish is a high-strength fluoride coating painted over the teeth, which Cochrane says is applied two to four times a year; our guide to fluoride explains it. healthdirect describes varnish as an alternative to sealants. The sources disagree on which is better for the grooves of back teeth:

  • A 2020 Cochrane review of 11 studies involving 3,374 children aged 5 to 10 found no clear difference between resin sealants and fluoride varnish, but the evidence was of very low certainty. It concluded that both reduce decay and that current evidence does not show one works better than the other. One small study suggested that using both may work better than varnish alone.
  • The American Dental Association says sealants work better. It recommends sealants rather than varnish for sealing the chewing surfaces of molars, citing three studies with nearly 2,000 participants in which sealants cut the risk of new decay by 73% compared with varnish alone.

In the UK, Delivering Better Oral Health recommends both for children at higher risk: sealants on the adult back teeth and varnish at least twice a year. See children's teeth.

What does it cost?

  • England: NHS dental treatment is free for children under 18 (or under 19 in full-time education). For adults who pay, the NHS lists sealants under Band 2.
  • Australia: healthdirect suggests asking your dental professional about the cost.
  • US: the NIDCR says some medical insurance, including Medicaid, and almost all dental insurance pay for sealants, and they are sometimes offered through schools.

See dental costs and help.

When to see a dentist
  • Your child's adult back teeth are coming through, and you would like to know whether sealants are right for them.
  • You are worried about your child's risk of decay, or their back teeth have deep grooves.
  • A sealant feels rough or chipped, or looks as if it has come off.

Frequently asked questions

Do fissure sealants hurt?

No. healthdirect says the procedure does not hurt and no anaesthetic is needed, and the Better Health Channel says no injections or drilling are involved.

Does my child still need to brush sealed teeth?

Yes. MouthHealthy says sealants are no substitute for brushing and flossing, and the NIDCR says children should still brush twice a day with fluoride toothpaste and have regular check-ups. See how to brush your teeth.

Can baby teeth be sealed?

Sometimes. The CDC says sealants can be applied to baby teeth, and the American Dental Association's guideline covers baby as well as adult molars. The NHS and Australian pages we read describe sealants for adult back teeth.

What happens if a sealant comes off?

healthdirect says sealants can wear down with chewing and sometimes need replacing. Your dental team will check them at your regular check-up and can reapply them if needed.

Sources

  1. Taking care of children's teeth, NHS, accessed September 2026
  2. What is included in each NHS dental band charge, NHS, accessed September 2026
  3. Gum disease (free NHS dental treatment), NHS, accessed September 2026
  4. Delivering better oral health, chapter 2: summary guidance tables for dental teams, Department of Health and Social Care and NHS England, accessed September 2026
  5. Delivering better oral health, chapter 4: dental caries, Department of Health and Social Care and NHS England, accessed September 2026
  6. Dental fissure sealants, healthdirect Australia, accessed September 2026
  7. Dental sealants, Better Health Channel (Victoria), accessed September 2026
  8. Fissure sealant, Australian Dental Association, accessed September 2026
  9. Dental sealants, American Dental Association, accessed September 2026
  10. Sealants, American Dental Association (MouthHealthy), accessed September 2026
  11. About dental sealants, Centers for Disease Control and Prevention, accessed September 2026
  12. Dental sealants, NIH National Institute of Dental and Craniofacial Research, accessed September 2026
  13. Sealants for preventing tooth decay in permanent teeth, Cochrane (Ahovuo-Saloranta and others, 2017), accessed September 2026
  14. Sealants or fluoride varnishes: which treatment is better for preventing decay in the permanent back teeth of children and adolescents?, Cochrane (Kashbour and others, 2020), accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.

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