Tooth Decay in U.S. Children Drops Sharply

Times Science Writer

Half the schoolchildren in the United States have never had tooth decay, and the rest have substantially fewer cavities than did children at the beginning of the decade, according to a major new survey released Tuesday by the National Institute of Dental Research.

Overall, cavities in schoolchildren’s teeth have been reduced by 36% since 1980, the survey found, while cavities between teeth--which are the most difficult to treat--have declined by 54% and are now rare.

Although the decline in tooth decay was uniform throughout the country, the incidence of cavities remained highest in the Northeast and along the Pacific Coast--a finding that has puzzled experts since the 1940s.


Government experts credited the improvement to increased use of fluoride in water, toothpaste and mouthwash, and noted that many of the remaining cavities could be prevented by new procedures that seal teeth in a plastic coating.

“What we are seeing is the beginning of the end for a disease that has plagued mankind throughout history,” said Dr. Harold Loe, director of the dental research institute, which is part of the National Institutes of Health in Bethesda, Md.

“It’s a pretty exciting thing to see that kind of success,” said Dr. James Saddoris, president of the American Dental Assn. “Now that we are solving the problem of cavities, it gives us the opportunity to work on other types of problems, such as periodontal (gum) disease and oral cancer.”

The new results were based on an extensive examination of 40,000 students between the ages of 5 and 17 at schools throughout the country during the 1986-87 school year. The students were selected as representative of the 43 million children in the United States.

Check Faulty Surfaces

Specially trained dentists counted the number of tooth surfaces--out of 128 surfaces in a typical set of 28 teeth--that had decay or fillings. A missing tooth was counted as five surfaces. Wisdom teeth were not included since few schoolchildren have them.

The mean number of surfaces that were decayed, filled or missing was 3.07 per child, said Dr. James P. Carlos, chief of epidemiology at the institute. A similar survey taken during the 1979-80 school year had shown a mean of 4.77 per child, indicating a 36% decline. The 1979-80 study had revealed a similar 35% decline in number of cavities since the early 1970s.


The survey found that the lowest incidence of tooth decay was in the Southwest--an area including Texas, New Mexico, Arizona and Colorado--with a mean number of 2.4 affected tooth surfaces per child. The highest incidence was in the Northeast, with an incidence of 3.6 surfaces per child. The Pacific Coast was second highest at 3.4 surfaces per child.

“Those differences by region were first discovered in the 1940s in studies of military recruits,” Carlos said in a telephone interview. “At first we thought it was due to different levels of naturally occurring fluoridation. But that explanation doesn’t hold up anymore because fluoride is everywhere and the differences are still there.”

Many Had No Cavities

The new study also found that, overall, 49.9% of the students had never had a cavity. The percentage of cavity-free students ranged from 97.3% among 5 year olds to 15.6% among 17 year olds.

In the 1979-80 study, only 36.6% of the students had never had a cavity. Carlos estimated that the corresponding number was only 28% in the early 1970s.

The new survey was not designed to find a cause for the decline in cavities, Carlos said, “but we are pretty confident that the explanation is the widespread use of fluoride. . . . The biggest decreases in cavities are on the smooth tooth surfaces where fluoride is known to be the most beneficial.”

Responding to the survey, Dr. Elizabeth M. Whelan, executive director of the American Council on Science and Health, a private health foundation, said it was “tragic” that nearly 40% of the U.S. water supply--including that of Los Angeles--is still not fluoridated. “Imagine what those numbers would be like if all of the water were fluoridated,” she said.


Toothpaste Fluoridated

More than 90% of all toothpastes are now fluoridated, and that provides a benefit in areas where the water supply is not treated, said Dr. Vladimir Spolsky of the UCLA School of Dentistry. Fluoride rinses are also often used in schools in such areas, he noted, and are providing “dramatic” decreases in cavities.

Researchers see great hope for continued reduction in cavities. More than two-thirds of cavities are now found on the chewing surfaces of teeth, Carlos said. Decay on these rough tooth surfaces some day could be “virtually eliminated,” he said, by the combined use of fluorides and adhesive sealants--plastic films painted onto teeth to seal out decay.

Dentists, meanwhile, are not particularly concerned about losing patients, according to Saddoris. “As you reduce tooth decay, you retain teeth longer as the population gets older,” he said. “That gives us so much more to do in the future.”

FEWER CAVITIES % of Children Nationwide Found Cavity-Free

Age ‘79-’80 ‘86-’87 5 95.4 97.3 6 89.7 94.4 7 76.5 84.2 8 58.6 75.0 9 50.6 65.5 10 37.9 55.7 11 33.7 45.0 12 26.9 41.7 13 21.1 34.0 14 19.6 27.7 15 14.9 21.8 16 11.8 20.0 17 10.7 15.6 All 36.6 49.9

Source: Nat’l Institute of Dental Research