Resin Filling Guide: Pros and Cons of Light-Cured Composite Resin, Health Insurance Rules Up to Age 12, Lifespan and Care

A resin filling is a treatment in which tooth-colored composite resin is placed in the space left after decay is removed and hardened with light. It has the advantages of removing little tooth, finishing in one visit and looking natural. In Korea, permanent-tooth cavities in children up to age 12 are covered by health insurance with a 30% copay for outpatient clinics, and other cases are uninsured, so the cost differs by dental clinic.

Published 2026-11-08 · Updated 2026-11-08 · DentalStatics editorial team

Key facts

Health insurance eligibility	Permanent-tooth cavities of children aged 5 to 12 (baby teeth excluded) (source: National Health Insurance Service (NHIS, 국민건강보험공단))
Excluded from health insurance	Resin treatment for wear, erosion, fracture or cosmetic purposes (source: National Health Insurance Service (NHIS, 국민건강보험공단))
Start date and copay rate	From January 2019, 30% copay at the outpatient clinic level (source: Ministry of Health and Welfare (보건복지부))
Benefit age expansion	Expansion by one year from the current 12 to 13 approved (September 2026) (source: Ministry of Health and Welfare (보건복지부))
Resin lifespan	Reported variously as 3.3 to 16 years (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)

What kind of material is resin and what are its pros and cons?

According to the KDCA National Health Information Portal, composite resin is a material made of organic polymer and inorganic filler, similar to tooth color and bonded to the tooth. Most use a light-cured type that hardens immediately under light, so it is placed directly in the mouth and finished in one visit.

Because it bonds to the tooth, there is no need to grind away extra healthy tooth to create retention shapes as with amalgam. On the other hand, it is weak against wear, so in wide areas that bear heavy chewing force it wears or breaks easily, and the margins can discolor from pigments such as coffee and tea.

Advantage: close to tooth color, little tooth removal, usable on both front teeth and molars
Advantage: completed immediately in the mouth, easy to refill just part of it
Disadvantage: lower wear resistance than other materials
Disadvantage: direct restoration is hard when the cavity is wide, and surrounding discoloration is possible

In which cases is it covered by health insurance?

From January 2019, the Ministry of Health and Welfare applied health insurance to light-cured composite resin fillings for permanent teeth up to age 12, with a 30% copay at the outpatient clinic level. Before that, only amalgam and the like were covered and resin was uninsured.

The National Health Insurance Service guides the eligible group as children aged 5 to 12 receiving resin fillings to treat cavities. Baby teeth are not eligible, and treatment for tooth wear, erosion, fracture or cosmetic purposes other than cavities is not covered either. In September 2026, a plan to widen the eligible age to 13 passed the Health Insurance Policy Deliberation Committee.

How long does resin last?

The National Health Information Portal explains that resin lifespan is reported in the literature as varying from 3.3 to 16 years, and that research standards are vague so it is hard to state precisely. If used for a long time it can break or develop secondary decay at the margin, so its condition is checked with regular checkups.

Cutting back on heavily pigmented things such as wine, green tea, black tea, curry, coffee and cigarettes can slow discoloration, and staining at the margin can be removed by polishing. One advantage of resin is that when part of it comes off, only that part can easily be refilled without replacing the whole thing.

What should you do if it is sensitive or painful after resin treatment?

Brief sensitivity to cold right after treatment is common and mostly decreases over time. The National Health Information Portal explains that side effects such as discoloration, sensitivity, gaps from bonding failure and nerve inflammation can rarely occur and are tending to decrease with improvements in materials and adhesives.

If it hurts when biting, the resin may have been filled slightly high, and a bite adjustment often helps. If it throbs on its own or the sensitivity gets progressively worse, nerve inflammation may have developed, and you need to check whether additional treatment such as root canal treatment is needed.

How does resin compare with other filling materials?

Besides resin, materials that fill cavities directly include amalgam and glass ionomer. The Ministry of Health and Welfare explained that until resin became covered, only amalgam and the like were insured, and even now in adult cavity treatment, whether it is covered and the copay differ by material.

If the cavity is wide and filling with resin carries a large risk of wear or breakage, an inlay made from an impression is considered. The National Health Information Portal explains that resin inlays, an indirect restoration, can be made more precise and stronger than direct restorations. It is good to decide with the dentist by weighing position, size, chewing force and cost together.

Common myths and facts

Myth: Resin is always a worse material than a gold inlay.

The National Health Information Portal explains that composite resin is gradually replacing amalgam and gold inlays even in molars. However, an inlay may be better where the cavity is wide or chewing force is high, so it is judged by size and position.

Myth: All children's cavities are covered by resin health insurance.

The covered group is permanent-tooth cavities in children up to age 12. Treating a baby-tooth cavity with resin is uninsured, and even for permanent teeth, fracture or cosmetic purposes other than cavities are not covered.

Myth: Resin is a harmful material for the body.

The National Health Information Portal describes composite resin as a material with extremely low risk to the human body. If you have concerns, you can ask the dentist about the material before treatment.

Frequently asked questions

Is resin treatment finished in one visit?

Small cavities are mostly finished in one visit. If there are several cavities or a deep one needs nerve-protecting treatment, treatment may be split up.

Does resin insurance cover baby-tooth cavities of a 12-year-old?

No. Resin health insurance applies only to permanent teeth, so for baby-tooth cavities you use another covered material or choose uninsured resin.

How much is the copay for insured resin?

The copay rate at the outpatient clinic level is 30%. The National Health Insurance Service webzine guided about 25,000 won, 30% of a benefit cost of about 85,000 won, which may vary with the number of surfaces filled, type of dental institution and fee changes.

When will it apply if resin insurance widens to age 13?

In its briefing on the September 2026 Health Insurance Policy Deliberation Committee results, the Ministry of Health and Welfare said it would widen the composite resin benefit from age 12 to 13. The exact start date is set by public notice, so confirm with the dentist or the NHIS before treatment.

My front tooth broke. Can it be repaired with resin?

If the broken area is small, the shape is often restored with resin. However, a fracture is not a cavity, so even for ages 12 and under it is not covered by resin insurance, and if the broken area is large or the nerve is exposed, other treatment may be needed.

References

Korean version →