Many fissure sealants stay in place for years, but not all of them, and a sealant only protects the grooves it still covers. A meta-analysis of sealant materials (Kühnisch and colleagues, Dental Materials, 2012) estimated that about 84 per cent of light-cured resin sealants were fully intact after five years. That leaves a share that wear, chip or lift, which is why each one is checked at routine visits and topped up when needed.
Why sealing the grooves works
The chewing surfaces of back teeth have narrow pits and fissures where plaque gathers and a toothbrush struggles to reach. Much decay in children's back teeth starts in these grooves. A sealant is a flowable resin painted into them and hardened, leaving a smoother surface that is easier to clean.
Sealants are most often placed on the first permanent molars soon after they come through, around age six, and on the second molars around age twelve. Our guide to when adult teeth come in explains that timing.
The evidence for children is good. A Cochrane review (Ahovuo-Saloranta and colleagues, 2017) found moderate-quality evidence that resin sealants on the permanent molars of children and adolescents reduced decay compared with no sealant over two years, with benefit still seen at four years. How large the benefit is depends on how likely the tooth was to decay in the first place.
Protection depends on the sealant staying whole
A sealant protects only the grooves it covers. If an edge chips or part of it wears through, plaque can collect in the exposed section again. This is not a failure of the treatment so much as its normal life cycle, and it is the reason a quick look at every check-up is part of having sealants.
How long a sealant lasts depends on the material, how well the tooth was kept dry while it was placed, and how hard the teeth are used. The same 2012 meta-analysis found that resin sealants were retained far better over five years than glass ionomer and several other materials. Grinding, chewing ice or hard lollies, and very hard biting can all shorten a sealant's life.
Checking and topping up a sealant
At a routine visit, the dentist or OHT looks at each sealant for wear, chips or lifted edges. If part has worn away, the area is cleaned, the enamel is conditioned and fresh sealant is added over the gap, bonding to what is left. Nothing is drilled away from the tooth, so an injection is not usually needed.
If decay has started underneath or beside a lost sealant, that area needs treatment instead, usually a small filling. Catching wear early makes this less likely. Our guide to a child's first filling explains what that involves.
Sealants cover the grooves, not the whole tooth
Sealants protect the chewing surfaces only. The sides of the teeth and the areas between them still rely on twice-daily brushing with fluoride toothpaste, cleaning between the teeth and keeping sugary snacks and drinks to a minimum. Our article on when children should start flossing covers the part sealants cannot reach.
Common questions
Do sealants need replacing?
Not routinely. They need checking, and a worn or chipped one is usually repaired by adding fresh material rather than starting again.
Will my child need an injection?
Usually not. Placing or repairing a sealant does not involve drilling away tooth, so most children find it an easy visit.
Can adults have sealants?
Yes, where the grooves are deep and still healthy and decay risk is higher. Our article on sealants for adults explains who is likely to benefit.
At Lumi Dental, our dentists and oral health therapists place and check sealants as part of children's routine care, and eligible children are bulk billed under the Child Dental Benefits Schedule. See our current deals page or read about family dental care at our Melrose Park practice. This article is general information and not a substitute for personal dental advice.
