Q: How early should I begin brushing my son's teeth? He's a year old and has six teeth. When should he see a dentist?

A: Cleaning should start as soon as teeth appear. You can brush your son's teeth with a soft-bristled brush before he goes to bed. If he resists the toothbrush, you can use a soft wet cloth. The idea is to remove all food and drink, especially sweet and sticky matter, from the teeth to prevent caries (cavity) formation. And don't let him take a bottle to bed. If you have gotten into this habit and cannot break it easily, fill the bottle with water only. Avoid sugary foods during meals and snacks, too. Even though these are "baby" teeth and will come out; if they become diseased, the permanent teeth that follow can be affected.

When your son gets a bit older, he will want to brush his teeth himself. You will need to supervise and perhaps even complete the job. Without considerable encouragement, young children rarely brush long enough and thoroughly enough to clean all tooth surfaces.

The amount of toothpaste on the brush, should also be monitored. Your son should brush with fluoride-containing toothpaste, but just enough to be seen on the bristle-tops. You want to minimize the likelihood that large amounts of toothpaste will be swallowed. Fluoride is essential for preventing cavities, and you should be grateful if there is fluoride in your drinking water. However, excessive amounts in the body can darken teeth.

When your son's permanent teeth come in, they will fit more tightly together then his baby teeth do. Permanent teeth require flossing to remove bits of food that are trapped. Children are not usually coordinated enough to floss well until they are eight or 10 years old.

Many dentists suggest children begin dental visits as early as one or two years of age. We would recommend that you wait no longer then age three and that your son see a dentist earlier if there are any signs of problems with his teeth. If your own dentist sees children, ask him or her when you should make an appointment for your son.

Dr. Wilson is director of general pediatrics at the Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.