Gingerbread is one of the staples at Christmas season and children should be allowed to indulge only once, dental experts say.

MCT / Terry Harris

SEATTLE — Here’s holiday advice from a dentist, if not a dietitian: Let your kids eat their sugary booty in one sitting.

Dental decay is on the rise again among U.S. preschoolers, and frequent treats may be one culprit. But the amount of starchy, sticky foods children eat may matter less than how often they eat them. That’s because enamel-eroding acids linger in the mouth for 20 minutes after each snack session.

So allowing your little princess to devour her holiday candy in one sitting instead of doling it out piecemeal is a lesser evil “from the point of view of cavities,” said Dr. Joel Berg, chair of the pediatric-dentistry department at the University of Washington.

Nearly 3 out of 10 American children ages 2 to 5 had visible tooth decay, according to figures released last year by the National Center for Health Statistics, based on surveys taken between 1999 and 2004. That’s a sizable jump from the 24 percent rate in the previous survey, taken between 1988 and 1994.

In older kids and adolescents, on the other hand, dental decay declined during the most recent period.

The worrisome state of oral health, especially for the youngest children, was the topic of a national summit of the American Academy of Pediatrics earlier this month in Chicago. The event was chaired by Dr. Wendy Mouradian, a physician who teaches both pediatrics and pediatric dentistry at the University of Washington.

The pediatrics academy has named oral health one of its top priorities for 2008, along with mental health and care for foster kids and other special-needs care.

Mouradian said early dental decay has a host of causes: Parents too often neglect care for baby teeth. Poor and uninsured children receive much less dental care than their peers. And a third of the U.S. water supply lacks fluoride, perhaps the single biggest defense against decay.

In response, pediatricians and family doctors are increasingly bridging the historical split between medicine and dentistry. The American Association of Medical Colleges has urged better oral-health training for medical students.

Relying on doctors as the first sentries against dental decay isn’t ideal, said Berg, who also is director of dental medicine at Seattle Children’s hospital.

But dentists realize that many young children see doctors numerous times before they ever recline in a dental chair. “A lot of parents think it’s OK to wait until age 3 or 4 before they have a first dental visit,” Berg said.

The American Academy of Pediatric Dentistry recommends that children see a dentist by their first birthday.

Dental decay is an infection, one that can lead to malnutrition, speech impediments and severe pain that can interfere with studies, among other problems. Berg said that every week he sees several children whose faces are swollen from severe infections. It’s not uncommon to see a 3-year-old with almost as many cavities as teeth, he said.

“This is a tremendous amount of disease,” Berg said. Yet, “we’re talking about a disease that’s preventable.”