Using a dental sealant (a thin plastic coating) is a safe, painless and low-cost way to protect your child's teeth from decay. Sealants have been used on children's teeth for more than 10 years.

The thin plastic coating is bonded to the chewing surfaces of the molars and premolars. The sealant forms a hard shield that keeps food and bacteria from getting into tiny grooves in the teeth and, therefore, prevents the teeth from decay.

The chewing surfaces of the back teeth have tiny grooves that form as each tooth develops. This is where most decays occur in children. That's because the bristles of a toothbrush can't get down into the grooves to remove trapped food and bacteria. Usually, sealants are used on molars and premolars. Fluoride from toothpaste helps protect the smooth surfaces on the front teeth and on the sides of the back teeth. But only sealants can keep food and bacteria from getting into the grooves on the chewing surfaces of the back teeth.

Sealants should be applied as soon as the first permanent molars (six-year molars) come in, usually when the child is between five and seven years old. The second molars (12-year molars) and the premolars should be sealed as soon as they come in. However, it's never too late to apply sealants, as long as the teeth are free of decay and fillings.

What about baby teeth?

The baby molars often don't need to be sealed. However, your dentist may recommend sealing the baby molars if there is a high risk of decay. Since baby teeth are 'space holders', losing baby molars from decay can cause crowding when the permanent teeth come in. Generally, all the back teeth can be sealed in one 30- to 60-minute office visit.

How are sealants applied?

The dentist, or another trained personnel in the dentist's office, applies the sealant. There is no numbing or pain. The treatment is done in three quick, easy steps.

1. The teeth are cleaned, dried and etched.

Any plaque (a bacterial film) is first removed from the teeth. Cotton rolls are placed around the teeth to keep them dry. Then each tooth is treated with a mild etching solution to kill any bacteria and to make the surface slightly rough. A rough surface helps the sealant to better adhere to the tooth.

2. The sealant is painted on and hardened. The chewing surface of each tooth is painted with liquid sealant using a small brush or applicator. The sealant is then hardened, usually with a special light.

3. The sealant is carefully checked. Each tooth is examined to be sure that the grooves are fully covered and that the sealant will not interfere with chewing. The sealant bonds to the tooth as it hardens and so your child can eat normally right away.

Follow up

Dr Dennis Jones - Peta-Gaye Clachar/Staff Photographer

The dentist or hygienist will look at the sealants at each regular dental check-up. Problems are rare and can almost always be corrected. Call the dentist if the sealants interfere with chewing or cause any sensitivity in your child's mouth.

How long do sealants last?

Sealants can last for many years. If they chip or come off, they can easily be replaced. Any problems can be detected and corrected at your child's regular dental check-ups. As long as the sealants are in place, decay cannot develop in the grooves. You can help the sealants last by encouraging your child not to chew on ice cubes or sticky candy.

Dr Dennis Jones is a dentist in private practice; email: yourhealth@gleanerjm.com.