This article is general information for our patients, not a diagnosis. Whether a particular tooth benefits from a sealant is a decision we make together at an exam.
The chewing surface of a back tooth isn’t flat. Under a light it looks like a tiny mountain range — ridges with deep, narrow valleys running between them (the “pits and fissures”). Those grooves are where nearly all decay in children starts, and the first thing I weigh when I look at a newly erupted molar is whether the brush can actually clean the bottom of them. Often it can’t: some grooves are narrower than a single toothbrush bristle. A sealant is simply a way of filling those grooves in so they stop collecting the plaque that leads to a cavity. Below I’ll walk through what they are, how well they work, and how I decide whether a tooth needs one.
Before we go further, it’s worth being clear on what a sealant is and isn’t. A sealant is a preventive measure, not a diagnosis or a cure. Deciding whether a particular tooth will benefit isn’t something I settle from a glance — it comes from reading a few things together: how deep and closed the grooves are, your child’s overall decay risk, whether the tooth can be kept dry long enough to seal it, and sometimes an X-ray to check nothing is already brewing between the teeth. Use this to understand the idea; the actual call happens in the chair.
What are pit and fissure sealants?
A fissure sealant is a material placed into the pits and fissures of a tooth to prevent or stop decay from starting there. In plain terms, it’s a coating — usually a tooth-coloured or lightly tinted plastic (resin) — that we flow into the grooves and then set hard so the surface becomes smooth and sealed. The name is a mouthful, but it’s descriptive: the pits are the little dimples and the fissures are the lines between the cusps, and those are exactly the spots the sealant covers.
They’re used almost entirely on the back teeth — the molars and premolars — because those are the teeth with the grooved chewing surfaces. Front teeth are smooth and rarely need them.
How do dental sealants work?
Sealants work by geography, not chemistry: a cavity needs a sheltered spot where plaque can sit undisturbed long enough to soften the enamel — and a deep groove is the perfect shelter. Seal the groove and you take away the shelter.
That matters because those chewing surfaces punch well above their weight for decay. They make up only about an eighth of all the tooth surfaces in the mouth, yet they account for around half of the cavities in school-age children. So a coating that protects just those surfaces still covers a large share of the risk. If you’d like the fuller picture of how a cavity actually starts, we cover that separately — sealants are one of the ways we interrupt that process before it gets going.
Are fissure sealants necessary?
Not on every tooth, and I’d be wary of anyone who says otherwise. The honest answer is that sealants are a risk-based decision. Every child benefits from fluoride and good brushing; a sealant is the extra step we add when a tooth’s grooves are deep enough, or a child’s decay risk is high enough, that brushing and fluoride alone may not be sufficient for that surface.
Where they earn their place, the evidence is genuinely good: across the research, molars that have been sealed develop roughly 60 percent fewer cavities than molars left unsealed, and for the grooved surface of an erupting molar a sealant tends to protect better than fluoride varnish on its own. That’s why, for a higher-risk child, I’ll often recommend sealing the first permanent molars soon after they come through. For a child at low risk with shallow, easy-to-clean grooves, regular fluoride and brushing may be all that surface needs.
Which teeth, and when?
The main target is the first permanent molars, which usually arrive around age six, and the second molars around age twelve. A tooth is most vulnerable to decay just as it’s coming through and in the couple of years afterwards, before the enamel has fully hardened and while it sits at the back where brushing is hardest — so that’s the window where a sealant does the most good.
Timing has a practical catch, though. To place the common resin sealant well, the tooth has to be kept completely dry while it sets, and a molar that’s only half-erupted with gum still over part of it can be hard to isolate. If a tooth can’t be kept dry, sealing it in a hurry does more harm than good, because a sealant that lifts at the edge can trap trouble underneath. In that situation we either wait until the tooth is up enough, or use the more moisture-tolerant material described below as a temporary measure.
What are sealants made of?
There are two main types, and we choose between them based on the tooth in front of us:
- Resin-based sealants. The usual choice, and the one with the strongest track record for staying put. They need a dry, fully erupted tooth. We clean the surface, apply a mild etching gel for a few seconds to give the enamel a slightly rougher grip, rinse and dry, flow the resin into the grooves, and set it with a blue curing light. The whole thing bonds to the enamel and lasts well.
- Glass ionomer sealants. These release a little fluoride and, importantly, tolerate a bit of moisture, so they’re useful on a tooth that’s only partly erupted or on a young child who finds it hard to keep still and dry. The trade-off is that they don’t hold up as long, so we often treat them as a bridge until a resin sealant can be placed properly.
What does it feel like to have one placed?
Having a sealant placed is gentle: there’s no drilling and no freezing — nothing is removed from the tooth. Your child sits back, we keep the tooth dry with cotton and a little suction, paint on the coating, and set it with a light. Start to finish it’s a few minutes per tooth, and most children are surprised it’s over so quickly.
That easiness is part of why I like sealants as one of the earliest things a young patient has done. A quick, easy, positive visit builds the kind of trust that makes everything afterwards easier — and if your child is anxious, our notes on how to help a nervous child feel at ease go into that further. If you’re new to all this, your child’s first dental visit walks through what to expect.
How long do sealants last, and do they need checking?
A sealant isn’t quite fit-and-forget: many stay fully intact for years — a good proportion are still completely in place a decade on — but chewing gradually wears them, and edges can chip or lift over time. That’s not a failure; it’s expected. What matters is that we look at them at each check-up and top up or replace any that have worn, because a sealant only protects the groove while it’s actually covering it. Kept an eye on and maintained, they go on doing their job for a long time.
Do sealants replace brushing and fluoride?
No — and this is the part I’m careful to be clear about: a sealant protects the grooved chewing surface, but it does nothing for the sides of the teeth or the spots between them. That’s where the other half of decay happens. Sealants are a complement to the basics, not a substitute: they sit alongside twice-daily brushing with a fluoride toothpaste, cleaning between the teeth, and sensible snacking. If you want to firm up the everyday side, our guide to everyday brushing and fluoride covers it. Think of a sealant as closing one door while good habits keep the others shut.
Are sealants safe? And can adults get them?
Yes, sealants are safe, and yes, adults can get them — the most common question I get is about BPA, since sealants are a resin. The reassuring answer is that the trace amount involved is very small and considered insignificant next to everyday sources, and the protection from a cavity avoided is real. Nothing is drilled or removed, so a sealant doesn’t weaken the tooth.
And it’s not only for children. Adults with deep, un-decayed grooves — especially anyone at higher decay risk, or who has watched cavities start on those surfaces before — can benefit from the same coating on a sound molar. The principle doesn’t change with age; it’s the shape of the tooth and your risk that decide it.
Sealants in Barrie, and what they cost
Because sealing a molar is quick and preventive, it’s one of the more affordable things we do, and it’s a covered benefit under most plans. Sealants for children are included under the Canadian Dental Care Plan (CDCP), which we accept, and we offer direct billing so most of the paperwork is handled for you. As a family-run practice with evening and Saturday appointments, we try to make the preventive visits the easy ones to keep.
If your child’s first molars have recently come through, or you’re wondering whether sealants make sense for your family, we’re glad to take a look and give you a straight answer — a plan for your teeth or your child’s, not a sales pitch. Call us at 705-721-9229 or book a visit or call us through our contact page, and we’ll fit you in as soon as we can.
This guide is part of our Children’s Dental Care library, where you’ll find the rest of our guides on prevention, first visits and looking after young teeth.
