Cavity germs swim in baby drool

U. ILLINOIS (US) — Infant saliva harbors bacteria associated with tooth decay and cavities—the most prevalent infectious disease in U.S. children.

“By the time a child reaches kindergarten, 40 percent have dental cavities,” says Kelly Swanson, professor of animal science at the University of Illinois. “In addition, populations who are of low socioeconomic status, who consume a diet high in sugar, and whose mothers have low education levels are 32 times more likely to have this disease.”

Swanson’s study, published in PLoS One, focuses on infants before their teeth erupt, unlike most studies that focus on children already in preschool or kindergarten—after many already have dental cavities.


“We now recognize that the ‘window of infectivity,’ which was thought to occur between 19 and 33 months of age, really occurs at a much younger age,” he says.

“Minimizing snacks and drinks with fermentable sugars and wiping the gums of babies without teeth, as suggested by the American Academy of Pediatric Dentistry, are important practices for new parents to follow to help prevent future cavities.”

For the study, Swanson and colleagues used high-throughput molecular techniques to characterize the entire community of oral microbiota, rather than focusing on identification of a few individual bacteria.

“Improved DNA technologies allow us to examine the whole population of bacteria, which gives us a more holistic perspective,” Swanson says. “Like many other diseases, dental cavities are a result of many bacteria in a community, not just one pathogen.”

Through 454 pyrosequencing, researchers learned that the oral bacterial community in infants without teeth was much more diverse than expected and identified hundreds of species.

This demonstration that many members of the bacterial community that cause biofilm formation or are associated with early childhood caries (ECC) are already present in infant saliva justifies more research on the evolution of the infant oral bacterial community, Swanson says.

“The soft tissues in the mouth appear to serve as reservoirs for potential pathogens prior to tooth eruption,” he says. “We want to characterize the microbial evolution that occurs in the oral cavity between birth and tooth eruption, as teeth erupt, and as dietary changes occur such as breastfeeding versus formula feeding, liquid to solid food, and changes in nutrient profile.”

Educating parents-to-be on oral hygiene and dietary habits is the most important strategy for prevention of dental cavities.

The study was funded by the United States Department of Agriculture-Cooperative State Research, Education and Extension Service.

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