Parents usually meet the term at a check-up, as a suggestion rather than a problem, and reasonably wonder whether it is necessary or an upsell.
Here is what they are and where they actually help — including where they do not.
What is a fissure sealant?
Look at the biting surface of a back tooth. It is not flat. It has a landscape of ridges and grooves — the fissures — and in many children those grooves are deep and narrow.
Narrower than a toothbrush bristle. That is the whole problem in one sentence. Food debris and plaque settle into a space that no amount of conscientious brushing can reach, and they sit there.
A sealant is a thin flowable material run into those grooves and set hard with a light. It fills the trap, leaving a smooth surface a brush can actually clean.
Why do back teeth specifically?
Because that is where childhood decay overwhelmingly starts. The first permanent molars — arriving around age six, often without parents noticing because no baby tooth falls out to announce them — have the deepest grooves and the longest working life ahead of them.
They are also right at the back of a young child’s mouth, which is the hardest place for them to brush well.
What is actually involved?
No drilling, no injection, and usually under ten minutes per tooth:
- The tooth is cleaned.
- A gel is applied for a few seconds to microscopically roughen the enamel so the sealant bonds.
- It is rinsed off and the tooth is dried thoroughly.
- The sealant is flowed into the grooves.
- A light sets it hard, and the bite is checked so it does not feel high.
The fiddly part is keeping the tooth dry — saliva contamination is the main reason a sealant fails early. That is why a wriggly four-year-old is a harder proposition than a settled eight-year-old, and why it is worth doing when a child can cooperate for a few minutes.
The timing that matters
| Tooth | Usually arrives | Best sealed |
|---|---|---|
| First permanent molars | Around age 6 | Soon after it is fully through |
| Second permanent molars | Around age 12 | Soon after it is fully through |
| Premolars | Ages 10–12 | If the grooves are deep |
| Baby molars | From about age 2–3 | Sometimes, if grooves are deep and decay risk is high |
Follow the teeth, not the birthday. Children erupt teeth on their own schedule, and a sealant placed on a tooth that is only half through will not seal properly.
There is a real reason to be prompt: a sealant works by keeping decay out. Once decay has already started in a groove, sealing over it traps it — so the assessment before placing one matters as much as the placement.
What sealants do not do
Being clear about the limits, because this is where expectations go wrong:
- They do not protect between the teeth. The contact surfaces where teeth touch are the other major site of childhood decay, and a sealant does nothing there. Flossing does.
- They do not replace brushing. They remove one hiding place, not the need to clean.
- They are not permanent. They wear, and they can chip off a hard-working molar. They need checking.
- They do not treat existing decay. A tooth that already has a cavity needs a filling.
- They are not needed on every tooth. Shallow, well-formed grooves that a brush can clean do not need sealing. Whether your child’s teeth have deep fissures is something to look at, not assume.
Does my child actually need them?
It depends on genuine risk factors rather than on a rule:
More likely worthwhile: deep, dark, narrow fissures you can see; a history of decay in baby teeth; a diet with frequent sugar; difficulty brushing thoroughly at the back; other family members with high decay rates.
Possibly not needed: shallow biting surfaces; no decay history; consistent brushing that reaches the back teeth properly.
An honest dentist will tell you which of those describes your child. If every child in a practice needs sealants on every molar, something other than clinical judgement is happening.
What it looks like at our clinic
At FTS Chin Dental in Likas we look before recommending:
- Whether the permanent molars are through, and how deep the grooves actually are
- Whether there is already decay in the grooves — which changes the answer entirely
- How your child’s decay risk looks overall, including what the baby teeth have done
- Whether your child can manage a few minutes of keeping a tooth dry
Children’s dentistry is priced at consultation, because what a child needs varies far more than an adult check-up does. There is a play corner in the waiting area, which helps the appointment start better than it otherwise might.
We see children of all ages, from first visits to teenagers.
For what routine cleaning appointments do and how often they are needed, see how often you actually need scaling. Our children’s dentistry page covers what else we do for younger patients.