The back teeth do the hard work of chewing, and their biting surfaces have deep grooves called fissures. These grooves can be narrower than a single toothbrush bristle, so food and bacteria settle in them and are almost impossible to clean out. That’s why most decay in children’s adult teeth starts on the chewing surfaces of the molars.
Fissure sealants are a simple, painless way to protect these grooves.
What is a fissure sealant?
A fissure sealant is a thin, tooth-coloured or white protective coating painted into the grooves of the back teeth. It flows into the fissures and sets hard, creating a smooth surface that’s easy to brush and keeps bacteria and food out. Sealants are made from resin or glass ionomer materials, and some release fluoride.
Which teeth are sealed?
Sealants are most often placed on the adult molars:
- First permanent molars, which come through around age 6 behind the baby teeth (often unnoticed, because nothing falls out to make room)
- Second permanent molars, which come through around age 12
Sometimes premolars or baby molars with deep grooves are sealed too, and occasionally adults with deep fissures and a high decay risk benefit.
Who benefits most?
Not every child needs sealants. Your dentist will recommend them based on:
- The shape of the grooves: deep, narrow fissures are higher risk
- Past decay: children who have had decay in baby teeth are more likely to get it in adult teeth
- Diet: frequent snacking and sweet drinks raise risk
- Brushing: newly erupted molars sit low at the back and are hard to reach
- Medical needs: children with conditions that make brushing difficult or decay more serious
The best time to seal is soon after the tooth has fully come through, before decay has a chance to start.
How sealants are applied
- Clean the tooth thoroughly.
- Keep it dry using cotton rolls or a small suction tip. This is the most important step, because moisture stops the sealant bonding.
- Prepare the surface with a mild solution so the sealant can grip, then rinse and dry.
- Paint the sealant into the grooves.
- Set it with a blue curing light, which takes a few seconds.
- Check the bite and smooth any high spots.
There’s no drilling and no needles. It takes a few minutes per tooth, and children can eat normally straight away.
How long do sealants last?
Sealants can last many years, but they wear and can chip or come off, especially in the first year. We check them at every check-up and top up or replace them when needed. A sealant that has partly come away can trap food, so regular checks matter.
Do sealants replace brushing?
No. Sealants protect only the chewing surfaces. Decay can still start between teeth and along the gum line, so brushing twice a day with fluoride toothpaste, cleaning between teeth once teeth touch, and limiting sugary snacks remain essential.
Are they safe?
Sealants have been used for decades and are considered safe and effective by dental organisations. Some people ask about BPA in resin materials; the exposure from dental sealants is extremely low and brief. If you have concerns, ask us about the materials we use, including glass ionomer options.
Cost and health funds
At Hornsby Dental, fissure sealants are $50–$100 per tooth. They’re a preventive item usually claimable under general dental extras. Sealing four molars typically costs far less than filling even one cavity, and avoids the drilling.
Other ways to protect children’s teeth
- Fluoride varnish at check-ups
- Drinking Sydney tap water, which is fluoridated
- Keeping sweet foods to mealtimes
- Water and milk as everyday drinks
- Helping with brushing until around age 8
- Six-monthly check-ups
See children’s dentistry and preventive dentistry.
Fissure sealant FAQs
Does it hurt?
No. There’s no drilling or injection. Some children don’t like the taste of the preparation solution, but it’s quickly rinsed away.
Can sealants be placed over early decay?
Sometimes, for very early decay limited to the enamel, sealing can stop it progressing. Deeper decay needs a filling.
Will my child notice them?
The tooth may feel slightly different for a day, then most children forget they’re there.
At what age should my child be checked for sealants?
Around age 6, when the first adult molars appear, and again around age 12. Regular check-ups make sure the timing is right.
Find out more about children’s dentistry in Hornsby.
Book a visit at Hornsby Dental
Hornsby Dental is at Suite 21, 14 Edgeworth David Avenue, Hornsby, about three minutes’ walk from Hornsby Station, with free street parking nearby. We’re open Monday to Friday 9am–6pm and Saturday 8:30am–4pm. Book online or call (02) 8090 1100.
This article is general information only. It isn’t a substitute for advice from your dentist about your own mouth and health.