What is a sealant?
It is a preventive treatment that seals the narrow, deep grooves on the biting surface of the molars with a sealing material (a flowable resin material), reducing the places where bacteria can stay. Its formal name is pit and fissure sealant. The biting surface of a molar is uneven like mountains and valleys, so cavities easily start in grooves so deep that toothbrush bristles cannot reach them.
Parents often ask, “My child’s molars don’t even have cavities, so why treat them?” The purpose is different from a composite filling, which removes an existing cavity and fills it. A composite filling treats a decayed spot, while a sealant seals a groove that has not yet decayed.
When is the best time to get sealants?
After the permanent molar has fully come up into the mouth, and before it starts to decay. The first permanent molars usually come in around age 6, and the second permanent molars around age 12. Newly erupted permanent teeth are also hard for children to brush.
However, I do not decide by age alone. I look at whether the tooth has fully come in, how narrow and deep the grooves are, whether decay has already started, and the child’s usual brushing and cavity risk together. If the grooves are shallow, food clears out easily, and brushing keeps them clean, I do not seal them unnecessarily.
For baby molars too, prevention can be discussed if the grooves are deep and the child gets cavities often, but the priority is the permanent molars that will be used for a long time.
Are sealants covered by health insurance?
For children aged 18 or under, cavity-free first and second permanent molars are covered by Korean National Health Insurance. If there is already a cavity or the tooth is not an eligible tooth, coverage is different. Whether it is covered can only be confirmed accurately by checking that surface directly at a checkup.
Are sealants placed on grooves that look dark?
| Current condition of the groove | Treatment |
|---|---|
| Deep, clean groove | After cleaning it, the sealing material is flowed in and hardened. It is not a drilling treatment |
| Groove with only staining | I do not call it a cavity based on color alone; after examination I decide whether it needs prevention or treatment |
| A spot that has already progressed inside | I do not cover over it. I confirm the cavity and fill it |
Not everything dark is a cavity, and even something that looks like a small dot can have progressed inside, so I look at X-rays as well when needed. Covering a groove that has already decayed inside is not a sealant. Cases where the teeth look fine on the outside but decay between them are written about separately in cavities between teeth.
Fluoride application is another preventive treatment I recommend alongside it. If a sealant blocks the grooves, fluoride makes the whole tooth surface a little harder and increases resistance to early cavities. The two do not replace each other.
If my child gets sealants, will they never get cavities?
No. A sealant only seals the grooves on the biting surface; it does not protect the surfaces between teeth or near the gums. Brushing and flossing still need to continue as usual. The sealing material can also wear or come off with chewing, so we check whether it is still there at checkups and reseal it if needed.
How we handle it at Wonjin Dental
I do not seal every molar automatically. If the grooves are deep and the cavity risk is high, I seal them in advance; if decay has already started, we go to a filling treatment instead. When sealing a clean groove, I do not drill the tooth; I clean the groove, flow in the sealing material, and harden it with light. Pit and fissure sealants are an insurance-covered item, and fluoride application is ₩30,000 (as of September 2026, all treatment fees).
Frequently asked questions
Do sealants hurt? Is anesthesia used?
When sealing a clean groove, there is no drilling, so it is usually done without anesthesia. For children, the hardest part is keeping their mouth open so that saliva does not touch the tooth.
How long do sealants last?
It depends on biting force and habits, but they often last for several years. Even if part of one comes off, it can be resealed at a checkup.
Can adults get sealants too?
Yes. If there are deep grooves without cavities, adults can also have them sealed for prevention, but insurance only covers children aged 18 or under, so for adults it is not covered by insurance.
Can my child eat right after getting sealants?
It is hardened with light right away, so eating right after treatment is fine. For the first day or two it may feel slightly high when biting, and if it keeps catching, we adjust the height.
