Cavity Prevention Guide: Brushing Frequency and Time, Fluoride Toothpaste Concentration, Snacking Habits and Checkup Intervals

The basics of cavity prevention are to remove plaque, the mass of bacteria, every day, to harden the tooth surface with fluoride, and to reduce the time sugar stays in the mouth. The KDCA National Health Information Portal recommends brushing at least twice a day for at least 2 minutes with fluoride toothpaste, and always brushing before bed. Adding floss, control of snacking habits, sealants for children and regular checkups reduces the chances of cavities forming and lets you find them while small if they do.

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

Key facts

Brushing frequency	At least twice a day with fluoride toothpaste; brushing before bed is essential (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)
Brushing time	At least 2 minutes, checking for missed spots in a mirror (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)
Fluoride toothpaste concentration	1,000 ppm or more for adults (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)
Brushing after acidic drinks	After about 30 minutes (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)
Regular checkups	Once a year if there is no oral disease; every 6 months if you have recently had treatment (source: Korea Disease Control and Prevention Agency (KDCA, 질병관리청) National Health Information Portal)
Sealant health insurance	Cavity-free first and second large molars up to age 18, 10% copay (source: National Health Insurance Service (NHIS, 국민건강보험공단))

How often and how long should you brush?

The National Health Information Portal generally recommends brushing at least twice a day with fluoride toothpaste, and stresses that brushing before bed must be done. This is because saliva decreases during sleep and its power to wash the mouth weakens. The other time can be set to suit your lifestyle.

If you brush for at least 2 minutes each time while looking in a mirror, it is easier to find spots you missed. The boundary between tooth and gum, the deep grooves on the chewing surfaces of molars, and the backs of the last molars are easy places to miss. Between the teeth, a toothbrush does not reach, so clean separately with floss or interdental brushes.

How do you make use of fluoride?

Fluoride stabilizes the crystal structure of the tooth surface so it withstands the acid made by bacteria. The National Health Information Portal recommends toothpaste with a fluoride concentration of 1,000 ppm or more for adults, and explains that rinsing daily with a fluoride mouth rinse also helps reduce cavities.

People who get cavities easily, and children, can also receive professional application, in which the dentist applies high-concentration fluoride. Professional application is recommended every 3 to 6 months, and in Korea fluoride application for cavity prevention is not covered by health insurance.

How should eating habits change?

Cavity risk depends not only on how much sweet food you eat but also on how often you put it in your mouth. The National Health Information Portal recommends reducing both the amount and frequency of sugary snacks and drinks, and avoiding them if possible if you have had cavity treatment in the last 3 years. Brush right after eating snacks.

Right after drinking an acidic drink such as a carbonated beverage, the tooth surface is weakened, so it is best to brush after about 30 minutes. The same material notes that using xylitol 3 to 4 times a day, including after brushing, can increase the preventive effect.

Eat a sweet snack in one go rather than nibbling it often
Cut back on the habit of sipping sweet drinks instead of water
After acidic drinks, rinse with water and brush after 30 minutes
After brushing before bed, take nothing but water

How often are checkups and preventive treatments needed?

The National Health Information Portal advises a checkup usually once a year if there is no oral disease, and every 6 months if you have recently had oral disease treatment. At a checkup, cavities between the teeth and the margins of old fillings, which cannot be seen with the eye, can be checked on X-rays.

Cavities form easily during elementary and middle school years when molars come in, so sealants that fill the grooves on the chewing surfaces of molars are recommended. Under health insurance, the copay for sealants on cavity-free first and second large molars of children up to age 18 is set at 10%, so the burden is small.

What more should people who get cavities easily do?

People with many treated teeth, with braces, with receded gums that expose the roots, or whose mouths are often dry because of medication get cavities more easily even with the same habits. In such cases, consult the dentist about shortening the checkup interval and getting regular professional fluoride application.

Around braces, clean above and below the appliance separately with a dedicated toothbrush and interdental brush, and with crowns or bridges, care separately for the margin and under the connected area. If your mouth gets dry at night, it is good to form the habit of moistening your mouth with water instead of drinking sweet drinks before bed.

Common myths and facts

Myth: The sooner you brush right after a meal, the better, always.

After a regular meal, brushing right away is good, but right after an acidic drink such as a carbonated beverage, the National Health Information Portal advises brushing after about 30 minutes.

Myth: Fluoride toothpaste must not be used for children.

The National Health Information Portal recommends fluoride toothpaste even for children under 2, and advises adjusting the amount to rice-grain size under age 3 and pea size for ages 3 to 6.

Myth: If you have no cavities, you do not need dental checkups.

Cavities do not hurt in the early stage, so they are hard to notice yourself. Even without oral disease, a checkup once a year is recommended.

Frequently asked questions

Does chewing xylitol gum alone prevent cavities?

Xylitol is only a supplementary measure and cannot replace brushing and floss. The National Health Information Portal explains that using it 3 to 4 times a day, including after brushing, can increase the preventive effect.

Is an electric toothbrush better than a regular one for preventing cavities?

With any toothbrush, the key is to clean carefully along the boundary between teeth and gums for at least 2 minutes. For people with awkward hand movements or difficulty cleaning thoroughly, an electric toothbrush can help.

From when should I use floss?

The National Health Information Portal advises using floss once teeth have come in. For children, a parent does it for them, and regular use helps reduce cavities between teeth and gum disease.

My mouth is often dry. Is that related to cavities?

Saliva neutralizes acid in the mouth and washes away food, so cavities form easily when saliva decreases. If dry mouth continues, check whether it is related to medication or a systemic disease, drink water often and shorten checkup intervals.

Can adults get fluoride applied at the dentist too?

Yes. The National Health Information Portal recommends professional fluoride application at least twice a year for adults at risk of cavities. However, since it is for prevention, it is not covered by health insurance.

References

Korean version →