Quick, name the most common chronic disease of childhood in the United States.

I bet you didn't say dental caries, or as any kid who has heard the ominous whirring sound of a dentist's drill would call them, "cavities." Fifty-nine percent of kids between 12 and 19 have at least one cavity, and poor and minority children are disproportionately affected, according to this study by the American Academy of Pediatrics.

On Monday, the academy issued new recommendations on tooth care, suggesting that parents start  brushing children's teeth, with fluoride toothpaste, as soon as they erupt.

"We’re still seeing a lot of cavities in very young children," said Rebecca Slayton, a pediatric dentist and member of the executive committee of the academy's section on oral health.  "Various national surveys show that we are making progress in some age groups, but in the younger age groups we are not."

Some of the problem stems from poor and immigrant children lacking dental care, but even among parents with the resources to get their children to dentists, there is a lack of awareness that baby teeth need the same care as permanent ones. And infants, of course, can't complain about tooth pain. Cavities are caused by bacteria in the mouth that erode tooth enamel, and the chances of getting them depend on diet, genetics, differences in saliva, the roughness of the tooth surface and the strength of a child's immune system, as well as oral hygiene, Slayton said.

Many parents don't take their children to their first dentist appointment until the kids are four or five years old, Slayton said. Dentists would like to see them when they are about a year old. Pediatricians, however, see newborns right away and can make important contributions to tooth care, she said, so the academy has sought to clarify its policies for them. In conducting that review, it moved in the direction of other groups, which recommend, among other things, that parents start brushing new teeth as soon as they erupt.

If you don't think dental care for children is a big deal, there is always the horrific case of Deamonte Driver, the Maryland 12-year-old who died in 2007 after a tooth abscess spread to his brain. What could have been an $80 tooth extraction ended up costing $250,000 in medical care for Deamonte, in part because his family couldn't find a dentist who would take Medicaid payments.

There is little danger of making even a 6-month-old sick with fluoride toothpaste. The only known side-effect is fluorosis of permanent teeth, which can produce stripes or opaque areas in permanent teeth that usually aren't noticeable and have no impact on health. And mostly gone are debates over fluoride in water, so many children are receiving fluoride that way.

The new recommendations call for brushing teeth as soon as they appear, but not with the large gob of toothpaste you see in most ads. Infant teeth need only a strip of toothpaste as long as a grain of rice. Apply it across the brush instead of lengthwise to accomplish this, Slayton said. When a child turns three, the amount of toothpaste can be increased to the size of a pea. The organization also recommends that pediatricians apply a sticky fluoride varnish every three to six months after teeth emerge. And they can prescribe systemic fluoride for children who aren't getting it in their water supply, as long as they know how much fluoride a child is getting overall. Fluoride rinses are not recommended for children.