A sealant is a thin coating flowed into the deep grooves on the biting surface of a back tooth and set hard. It seals off the one place a toothbrush physically cannot reach — and that is where most decay in children begins.
The appointment takes a few minutes per tooth, involves no drilling and usually no anaesthetic, and it is one of the highest-value preventive treatments in children’s dentistry.
Why the grooves are the problem
The biting surface of a molar is not flat. It has a pattern of fissures running across it, and in many people those fissures are deep and narrow — narrower than a single toothbrush bristle. Food and plaque fall into them and stay there. No amount of good brushing gets to the bottom.
That is why decay in children starts on the biting surfaces of back teeth far more often than anywhere else, and why a child who brushes reasonably well can still develop a cavity there.
A sealant fills the groove with a material the brush can clean across, turning an uncleanable surface into a cleanable one.
Which teeth, and when
The main targets are the first permanent molars, which erupt around age six at the back of the mouth without any baby tooth falling out first, and the second permanent molars, which arrive around age twelve.
The six-year molars deserve particular attention. Many parents never notice they have arrived, because nothing is lost to make room for them and they appear behind the existing teeth. They are permanent, they have to last a lifetime, and they erupt at exactly the age when a child’s brushing is least reliable — see why baby teeth matter.
Sealants are placed as soon as practical after the tooth has erupted enough to be kept dry during the procedure, which is what the timing depends on. Baby molars are sometimes sealed too, where a child is at higher risk of decay.
What the appointment involves
- The tooth is cleaned.
- A conditioning gel is applied for a few seconds and washed off, which gives the surface a microscopic texture for the sealant to grip.
- The tooth is dried and kept dry — this is the part that actually matters, because moisture contamination is the main reason sealants fail.
- The sealant material is flowed into the grooves.
- It is set with a curing light.
- The bite is checked and adjusted if it feels high.
No drilling, no injection, a few minutes per tooth. Most children find it an easy appointment, which makes it a good early experience for a child who is nervous.
How long they last, and what to expect
Sealants wear with chewing and can chip or partially come away over the years. Well-placed, they commonly last several years, and they are checked at every routine visit and topped up or replaced when needed. That checking is part of what makes them work — a partially lost sealant that nobody notices can trap plaque rather than excluding it.
They may feel slightly odd for a day or two, and a child may say the tooth feels “high”. Tell us if that persists; it is adjusted in a moment.
What sealants do not do
A sealant protects the biting surface. It does nothing for the surfaces between the teeth, where the other main pattern of childhood decay occurs, and nothing for the gum line. It is not a substitute for brushing, for flossing where teeth touch, for fluoride, or for controlling how often sugar reaches the teeth — see tooth decay in children.
They also cannot be placed over an existing cavity. If decay is already present, that is treated first.
Are they safe?
Sealants are a long-established preventive treatment used routinely worldwide. Some parents ask about the materials used; if you have a specific concern, raise it at the appointment and it can be discussed, including what alternatives exist. The relevant comparison is not sealant against nothing, but sealant against the drilling and filling that decay in an unsealed groove leads to.
How to tell whether your child already has them
Parents frequently do not know, and it is worth checking rather than assuming.
Look at the biting surfaces of the back teeth in good light. A sealed tooth has a smooth, slightly glossy surface where the grooves would be, often faintly white or tooth-coloured against the natural tooth. An unsealed molar shows distinct dark lines running across the surface.
The simplest approach is to ask at the next appointment: which of my child’s teeth are sealed, and are any due? It is a specific question with a specific answer, and it is the kind of thing that otherwise falls between appointments.
Why the six-year molars deserve particular attention
These are the teeth this treatment exists for, and they are the ones most often missed.
They erupt around age six at the very back, behind all the existing baby teeth. Because nothing falls out to make room for them, most parents never register their arrival and assume the back teeth are still baby teeth that will be replaced. They will not be — these are permanent and they have to last a lifetime.
They also arrive at the worst possible moment: at an age when a child’s brushing is unreliable, in the least accessible part of the mouth, with grooves that are deep and freshly formed. That combination is why they are the most commonly decayed teeth in childhood.
Two practical things follow. Get them sealed when they come through. And when you brush your child’s teeth, deliberately reach behind the last tooth they had before — it is a real place and almost everyone misses it.
What happens if a sealant is lost
Sealants wear, chip and sometimes come away partially. A partially lost sealant is worse than no sealant at all, because it creates a ledge that traps plaque rather than excluding it — which is precisely why they are checked at every routine visit and topped up or replaced.
This is also why sealants are not a substitute for attending. A sealed tooth in a child who stops coming for three years is not protected in the way the parent assumes.
What they do not replace
A sealant covers one surface of one tooth. It does nothing for the surfaces between teeth, which is the other main site of childhood decay and the one that needs flossing, and nothing for the gum line. It also does not change how often sugar reaches the teeth, which remains the single largest factor — see preventing early childhood decay.
Frequently asked questions
Does it hurt?
No. Nothing is drilled and no injection is needed in a normal sealant appointment.
Can adults have sealants?
Yes, where the grooves are deep and sound. It is less common simply because by adulthood many back teeth already have fillings.
My child already has fillings. Is it too late?
Not for the teeth that are still sound. Sealing the unaffected molars is worthwhile.
Will I be able to see them?
They are tooth-coloured or clear and sit only in the grooves, so they are not noticeable in normal conversation.
Do they replace check-ups?
No — they need checking, and the rest of the mouth still needs examining. See what happens at a child’s check-up.
Ask whether your child’s molars should be sealed
If your child is around six or twelve, it is worth asking specifically at the next visit. See our pediatric dentistry page and our cavity protection page.
To arrange a consultation at our clinic on Abbas El-Akkad in Nasr City, call +20 101 969 7597 or message us on WhatsApp.
