New research suggests baby teeth may be fruitful providers of stem cells.

The research, conducted by a group of cell biologists at the National Institutes of Health and the Institute of Medical and Veterinary Science in Australia, is published in Monday's issue of Proceedings of the National Academy of Sciences.

Initial findings suggest baby teeth could become a more easily accessible and far less controversial way to get stem cells.

The researchers said the stem cells remain alive inside the tooth for a short time after it falls out of a child's mouth, suggesting the cells could be readily harvested for research.

But they found that adult teeth don't cut it. They said stem cells from baby teeth showed higher rates of growth and duplication than stem cells derived from bone marrow and adult teeth.

The researchers were also able to make the baby teeth stem cells develop into more tissue types.

"Doctors have successfully harvested stem cells from umbilical cord blood for years," said Dr. Songtao Shi, a scientist at NIH's National Institute of Dental and Craniofacial Research and the senior author on the paper. "Our finding is similar in some ways, in that the stem cells in the tooth are likely latent remnants of an early developmental process."

Children normally develop a set of 20 deciduous, or "baby," teeth, which appear when an infant is about six months old and are generally replaced, one tooth at a time, between age 6 and 12.

The new finding, as so often happens in science, stems from a chance interaction.

Shi said it happened one evening when his then 6-year-old daughter, Julia, asked for help in pulling out a loose baby tooth.

"Once it was out, we sat and looked carefully at the tooth," said Shi, a pediatric dentist. "I said, 'Wait a minute, there is some red colored tissue inside of the tooth,' so I took the tooth to my laboratory the next day and examined it. Sure enough, it had beautiful pulp tissue left over."

A few days later, when another of Julia's teeth came out, Shi said he was better prepared. He placed the tooth into a liquid medium used to culture cells, drove it to the laboratory, and extracted the dental pulp. Soon thereafter, he isolated living stem cells from the tissue, a discovery that would lead to the collection of more exfoliated teeth from Julia and other children.

Then the research team began studies to determine whether the cells would grow well in culture. Using dental pulp extracted from children's incisors, they discovered that about 12 to 20 stem cells from each tooth had the ability to colonize and grow in culture.

Ronald Kalil, a professor of neuroscience at the University of Wisconsin-Madison Medical School, is concerned about the findings. He said the research doesn't indicate how many stem cells developed into other tissue types.

Scientists hope to someday manipulate stem cells to grow into all kinds of adult cells.