Kids' Cavities, Fluoride and Sealants: How Do I Protect Baby and Adult Teeth?

Why do kids get cavities?

Cavities form when bacteria in the mouth make acid that harms enamel. NIDCR says tooth decay begins when bacteria in your mouth make acids that attack the surface of the tooth, which is the enamel. NIDCR says that when decay-causing bacteria meet sugars and starches from foods and drinks, they form acid.

Even babies can get cavities. The AAP says 23% of all kids will get cavities before their fifth birthday. It also says even the natural sugars in breast milk and formula can start the process. Baby teeth are small and their enamel is thin, so decay can move quickly.

This is not about blame. Most parents are doing their part. The goal is to know what raises the risk and what lowers it. Our guide on cavities explains how decay works in teeth of any age.

What is early childhood caries?

Early childhood caries means tooth decay in a very young child. NIDCR says young children are at risk for early childhood caries, sometimes called baby bottle tooth decay, which starts in the baby’s front teeth and extends to the back teeth.

The AAP lists habits that raise the risk. Putting a child to sleep with a bottle lets sugars from formula and breast milk linger on the teeth. Letting a child sip sweet drinks through the day does the same.

A clean, damp cloth on the gums after meals, brushing as soon as teeth appear, and water between meals are simple counters. The next table sets out habits that help and habits that raise risk.

What do early cavities in a child’s teeth look like?

Early signs can be easy to miss. The AAP lists white spots on the teeth as a sign that the tooth is losing the calcium and minerals that keep it strong. It lists tan, brown or black spots, or pits, as a sign that the tooth is decaying.

NIDCR adds that in early decay there are usually no symptoms, so a child may not complain. That is why regular dental visits matter. A dentist can find early spots before they turn into holes, when fluoride and good care may help the enamel.

If you see a white, brown or black spot on your child’s tooth, or a small pit, make an appointment. Do not wait for pain.

Which drinks and snacks are friendlier to teeth?

Water is the drink to choose every day. The AAP says regular tap water, which usually contains fluoride, is the healthiest drink for your child’s teeth. It also says fruit juice, soda and sweetened drinks are not good for a little one’s teeth, and that after age one, juice should be limited to 4 ounces a day and mixed with water.

Sticky snacks can cling to teeth. The AAP lists raisins and other dried fruits, gummy candies, taffy, fruit roll-ups and snack bars with honey or molasses. If your child eats them, have them brush or rinse with water afterward.

Timing matters as much as the food. A snack at a set time causes one acid attack. Sipping or grazing all day causes many. Plan meals and snacks, and offer water between them.

How does fluoride protect teeth?

Fluoride makes enamel stronger and helps repair early damage. The ADA says fluoride is a naturally occurring mineral that helps prevent tooth decay by making the surface of the teeth stronger and more resistant to cavities. It also says fluoride helps repair the damage acids can do, a process called remineralization.

For young children, the ADA says teeth benefit from fluoride even before they break through the gums, through the food and drink a child takes in. Once teeth are in, fluoride toothpaste, fluoride in drinking water and treatments at the dentist all add to the protection.

NIDCR says enamel can repair itself using minerals from saliva and fluoride from toothpaste, or from fluoride applied by a dentist or hygienist. That repair works at the early stage, before a hole forms. After a cavity forms, the tooth needs treatment. NIDCR says dentists commonly treat cavities by filling them. You can read about dental fillings on the practice’s page.

Is fluoride safe for children?

The ADA says that for more than 70 years the scientific evidence has shown that adding fluoride to community water supplies is safe and effective. The AAP also describes fluoride as a safe and useful cavity-fighting ingredient. Both stress using the right amount.

Amounts matter, because young children may swallow toothpaste. The ADA says to supervise children aged 3 to 6 so that they use the right amount and do not swallow too much. It also says children under age 6 should not use mouthwash unless a dentist recommends it, since they may swallow it instead of spitting.

If you have a question about fluoride for your child, ask your dentist or your child’s doctor. They know your child’s health and water source. Community water fluoridation is a public health topic, and you may see debate about it. Look for sources you can check.

How much fluoride toothpaste should a child use?

Use a small amount, and add help as your child grows. The ADA gives this guide by age.

The ADA says to teach children to spit out toothpaste. The AAP says to teach your child to spit without rinsing. If your child is under 6, skip fluoride mouthwash unless your dentist suggests it.

Does our water have fluoride?

It depends on your water supply. The AAP says to check with your local water utility to find out if your water has fluoride. The ADA says the current recommendation is that communities adjust fluoride levels to 0.7 milligrams per liter of water.

For one local data point: Missouri American Water reported 0.59 ppm fluoride in its 2025 annual water quality report, with a range of 0.49 to 0.59 ppm (report dated March 27, 2026). That is a report number, not a judgment, and it covers the system named in the report. Your own address may be served by a different supplier, and some homes use private wells.

Check your water bill or call your utility to learn which report applies to you. If your home uses a private well, the AAP says to ask your doctor whether your child should have a prescription for fluoride drops or chewable tablets. The ADA says such supplements may help children aged 6 months to 16 years who live where fluoride is not added to local water. Your dentist or pediatrician can advise you.

What are fluoride varnish and in-office fluoride treatments?

These are fluoride products applied by a dental team. The ADA says a dentist may apply fluoride directly to the teeth during a visit, and that this treatment is often recommended for children to prevent early cavities. The AAP says a pediatrician or dentist may apply fluoride varnish two to four times a year, and that it can continue as a child grows.

Fluoride varnish is a surface treatment painted on the teeth. Ask your dentist whether it fits your child, and how often. The practice’s family dentistry text mentions fluoride treatment for children as something it may recommend.

What are dental sealants, and who needs them?

Sealants are thin protective coatings on the chewing surface of back teeth. NIDCR says they are thin plastic coatings that protect the chewing surfaces of children’s back teeth from cavities. The pits and grooves on those teeth can trap food and germs that a toothbrush cannot reach.

The ADA says sealants have been shown to reduce the risk of decay by nearly 80% in molars, and that they are no substitute for brushing and flossing. Sealants can even be placed over areas of early decay to prevent further damage, so a dentist can watch the tooth.

The practice describes its approach on its dental sealants page. Our insurance and financing page shows how to ask about coverage.

How often should kids see the dentist?

It depends on your child’s risk. The AAP says that at the first visit, the dentist can check your child’s teeth and set the frequency of future checkups. Regular visits catch early decay, when treatment is simplest, since NIDCR says early decay usually has no symptoms.

Read about timing and what to expect in our guide to your child’s first dental visit.

Next step

Learn how the practice describes care for children on its dentistry for kids page. Then call (636) 273-5866, Monday to Thursday, or request an appointment. Bring your child’s toothpaste and ask the team to check the amount and technique.