Fissure sealants are one of the simplest, cheapest, most evidence-supported things we can do to protect a child’s adult back teeth. They take about ten minutes per tooth, no drill, no anaesthetic, no aftercare beyond the usual brushing, and good evidence shows they reduce decay on treated surfaces by roughly 70 to 80 percent over the first few years.
If you’re weighing up whether your child needs them, our children’s dentistry service covers sealants as part of routine NHS care, and there’s no extra charge because NHS dental treatment is free for children under 18 in England (and under 19 in qualifying full-time education). The decision is purely clinical: does this child’s tooth anatomy and decay risk warrant a sealant, and is now the right time to apply one?
What a fissure actually is
The chewing surfaces of your back molars aren’t flat. They’re a landscape of ridges and grooves designed for grinding food, and the deep narrow valleys between those ridges are called fissures. Some children have shallow, easy-to-clean fissures. Others have fissures so deep that a single bristle of a toothbrush can’t physically reach the bottom.
Bacteria, plaque, and food particles do reach the bottom, of course. The result is exactly what you’d expect: decay starts in the fissure and works its way down, often invisibly from the outside until it hits the dentine.
That’s why a back molar can look perfectly fine on a casual glance and still have an active cavity hidden inside it.
How sealants work
A sealant is a thin layer of liquid resin (or sometimes glass ionomer) that we paint into the cleaned fissure and harden with a small light. Once set, it physically blocks bacteria and food from reaching the vulnerable enamel underneath. The tooth surface above the sealant becomes smooth, which means a toothbrush can clean it properly.
The whole process for one molar runs roughly like this:
- Clean the tooth thoroughly with a small rotating brush and prophy paste
- Isolate the tooth so it stays dry (cotton rolls or a small dam)
- Apply a mild etching gel for about 20 seconds, then rinse and dry
- Paint on the sealant resin so it flows into every crevice
- Cure with a blue light for 20 to 40 seconds
- Check the bite and polish off any high spots
No injection, no drilling, no scary noises. Most children describe it as “a bit weird but not painful”. The taste of the etch gel is the most common complaint, and that’s gone within seconds.
Which teeth get sealed and when
The first permanent molars usually erupt around age 6, often without parents noticing because they come through behind the baby teeth rather than replacing one. The second permanent molars follow around age 12. These are the four teeth at each corner of the mouth that we’re most likely to seal.
The window for sealing is fairly tight. We want the tooth fully erupted, dry, and uncontaminated, but we also want to seal it before any decay has started. In practice, we assess at each six-month check-up and recommend sealing as soon as the tooth is high enough above the gum to keep dry during the procedure.
| Tooth | Typical eruption | Best time to seal | Why |
|---|---|---|---|
| First permanent molars | Age 6 to 7 | Within 12 months of full eruption | Deep fissures, high decay risk early |
| Second permanent molars | Age 11 to 13 | Within 12 months of full eruption | Often deeper fissures than firsts |
| Premolars | Age 9 to 12 | Only if at high risk | Generally shallower fissures |
| Wisdom teeth | Age 17+ | Rarely sealed | Difficult access, often extracted later |
Which children benefit most
Sealants aren’t automatic for every child. We assess each case based on:
- Depth and shape of the fissures (some are flat enough to skip)
- Existing decay history in baby teeth
- Diet and brushing quality at home
- Any medical conditions affecting saliva or enamel
- The child’s ability to keep the tooth dry during the procedure
In our experience, the children who benefit most are those whose first permanent molars come through with visibly deep, dark grooves and whose baby molars have already needed fillings. For those children, sealing the firsts as soon as they’re up is essentially preventive insurance.
A child with shallow fissures, no decay history, and excellent home care may not need sealants at all.
How long sealants last
A well-applied sealant on a fully erupted, dry tooth often lasts five to ten years, sometimes longer. We check them at every routine appointment and top up or replace as needed. Some children come back at age 14 with the sealant we placed at age 7 still completely intact. Others lose part of one within a year, usually because the tooth wasn’t quite high enough at the time of placement.
If a sealant chips or wears, it doesn’t suddenly mean the tooth is decayed. It just means we need to repair or replace the sealant before bacteria can find their way back into the fissure. That repair is also free on the NHS and takes only a few minutes.
Common questions parents ask us
Worth knowing: a sealant doesn’t change the colour of the tooth in any obvious way. The resin is usually clear or very faintly tinted, and once it’s polished, you’d struggle to see it in a mirror.
Sealants don’t replace brushing. They protect the chewing surface, but the smooth sides and the gumline are still vulnerable. Twice-daily brushing with fluoride toothpaste is just as important after sealing as before.
Sealants don’t contain mercury. They’re a plastic resin, similar to white filling material, and the BPA exposure from a sealant is well below the levels we get from normal day-to-day food packaging. The NHS overview of decay treatment includes sealants as a standard preventive measure.
If you’d like a properly detailed dive into the evidence, the Cochrane reviews on pit and fissure sealants summarise dozens of trials and consistently show meaningful decay reduction.
Booking sealants and what the appointment is like
If your child is around 6 or 12 and you’ve not had sealants discussed at a recent check-up, please mention it at the next visit, or ring ahead so we can plan time for the procedure. We can usually examine, clean, and seal in a single appointment if the child is comfortable.
For children who are particularly anxious, we sometimes split the visit. The first appointment is just an examination and a polish, so the child gets used to the chair and the noises. The second appointment, a fortnight later, is the actual sealing. That sounds like overkill for a ten-minute procedure, but for a nervous seven-year-old it’s the difference between a successful sealing and a refused one. Two short calm visits beats one stressful long one every single time.
After the appointment, your child can eat and drink normally straight away. There’s no soreness, no numbness, and no aftercare beyond the usual brushing twice daily with fluoride toothpaste. We’ll check the sealant at every six-monthly visit and top it up or replace it if any part has worn or chipped.
You can reach our team at Westcliff Dental Practice on 01702 344 500. We see children of all ages on the NHS, and we’re happy to talk through whether sealants are right for your child before you book, particularly if previous dental visits have been difficult or your child is anxious about new procedures.
