Parents nod politely when I say the word sealant and then ask, reasonably, what one actually is. It is one of the least dramatic things we do and one of the most useful, so it is worth five minutes of plain explanation.
What a sealant is
Look at the biting surface of a back tooth in good light. It is not flat. It is a landscape of ridges and narrow grooves — pits and fissures, in the trade — and some of those grooves are deeper and narrower than a toothbrush bristle. Bacteria and food debris are very much smaller than a bristle. That is the whole problem in one sentence: there are places on a molar that cannot be cleaned, however conscientious the brushing, and those are the places where decay in children most often starts.
A sealant is a thin liquid resin flowed into those grooves and hardened in place, turning a valley nobody could clean into a smooth surface a brush can sweep across. It sits on the tooth rather than in it. Nothing is drilled away to make room for it.
Which teeth, and when
- The first permanent molars, at around six. These arrive behind the last baby teeth without anything falling out first, so a great many parents do not notice them come through at all. They are the teeth most likely to need a filling in childhood, and the first ones we would seal.
- The second permanent molars, at around twelve, once they are far enough through to keep dry.
- Sometimes premolars, if their grooves are deep, and sometimes baby molars for a child whose risk is high.
Not every tooth needs one. A molar with shallow, smooth, self-cleaning grooves may be better left alone. We look at the tooth, at the rest of the mouth, and at the child's decay history, then tell you which ones we would seal and which we would watch. If the answer is that nothing needs sealing yet, that is a perfectly good answer and you will get it.
What the appointment feels like
This is the part children want to know and the part that is easiest to describe honestly, because there is nothing in it that hurts.
- We clean the tooth and show it to your child in a mirror.
- We dry it and keep it dry with cotton rolls, or occasionally a rubber dam. Staying dry is the whole trick — a sealant placed on a wet tooth will not stay on, so we would rather stop and start again than rush this bit.
- A gel goes on for a few seconds to roughen the enamel very slightly. It tastes sour. That is the worst thing that happens.
- Rinse, dry again.
- The sealant is flowed into the grooves with a fine tip.
- A blue light, held close for twenty or thirty seconds, sets it hard. It is bright but not hot, and your child wears the orange glasses, which are widely considered the best part.
- We check the bite with a strip of coloured paper and smooth off anything that feels high.
A few minutes per tooth. No injection, no drill, no numbness, and no waiting afterwards — they can eat lunch on the way home. The genuinely hard part, for a small child, is holding still with their mouth open for several minutes in a row, which is why we often do two teeth at one visit rather than four.
How long they last
Years, usually, but not forever and not uniformly. Sealants wear under chewing, and they can chip at the edges or come away entirely, sometimes without anyone noticing. A sealant that is half there is not doing the job it was placed to do, and it can shelter the very thing it was meant to keep out.
So a sealant is not a thing we do once and forget. We look at every one of them at every check-up, and we repair or replace the ones that need it. That maintenance is part of what makes them work, and it is a good reason not to skip a routine appointment on the grounds that nothing is hurting.
What they do not do
A sealant protects the chewing surface. It does nothing at all for the surfaces between the teeth, where the other common childhood cavities start, and nothing for the gum line. It is not a coating over the whole tooth and it is not a substitute for anything.
Brushing twice a day with fluoride toothpaste, flossing where teeth touch, fluoride varnish at check-ups and keeping the number of sugar occasions down all still matter exactly as much as they did before. If you want the everyday version of that, my colleague Marisol has written brushing without a battle.
Sealing over very early decay
Occasionally we will place a sealant over a groove that already shows very early decay — a lesion that has demineralised the enamel but has not yet broken through into a cavity. Sealing such a tooth can arrest that early damage by cutting off what feeds it. It is a legitimate and well-described approach, but only with supervision: regular review, and radiographs where they are indicated, so that anything progressing underneath is caught rather than hidden.
If we are doing that on your child's tooth we will say so in those words, not in passing, and we will show you the photograph before and the photograph after. You should never find out afterwards that a sealant was doing more than it appeared to be doing.
Sealants for children are a covered benefit under Ohio Medicaid, and most private plans cover them too, though plans differ on which teeth and how often. We check your cover before we book, not after — see insurance and Medicaid.
The clinical detail, alongside cleanings and fluoride, sits on cleanings, fluoride and sealants.