Smile, baby -- those teeth are lifesavers

In future, the tooth fairy may leave children something more than a silver coin in a glass of water, in exchange for their lost milk teeth.

Researchers at the Hanson Institute in Adelaide believe pluripotent stem cells from those deciduous teeth could help sustain their owners' dental, skeletal, neural and cardiovascular health well into the autumn of their lives.

Dr Stan Gronthos' research team at the institute has identified teeth -- milk teeth, in particular -- as a rich source of stem cells.

The institute's director, Prof Howard Morris, said teeth were potentially a much more convenient and less invasive source of stem cells than bone marrow.

The teeth contain mesenchymal stem cells that, while not matching the versatility of haemopoietic stem cells from bone marrow, or the totipotent capabilities of embryonic stem cells, are capable of forming teeth, bone, heart and skeletal muscle, and even new neurons for aging brains.

"The availability of adult stem cells has been one of the major issues confronting the clinical use of stem cells for repairing tissues," Morris said.

"The presence of adult stem cells in teeth offers a way around the problem -- we lose our deciduous teeth naturally, and many people have their wisdom teeth extracted in teenage. Even having a tooth extracted is not a major, invasive operation, like having bone marrow extracted.

"If necessary, someone with a life-threatening condition could donate a tooth to generate stem cells for organ repair, knowing that they would have no problems with any organs or tissues grown from them would be autologous, so there would be no problems with immunological rejection."

Morris said the main problem was storing the cells over the longer term and expanding them when required -- they could not be maintained indefinitely in culture because they could only divide around 40 times before their shortening telomeres began to cause chromosomal abnormalities.

"The other challenge, which we're now tackling, is to identify the pathways by which the cells can be induced to develop into particular tissue types, like bone and muscle," he said. "We have an NHMRC grant to do research in animal models into replacing teeth and jaw bone with tissues grown from stem cells."

He said the stem cells could be used to regrow teeth, or to repair bone damaged by periodontal disease. Solving the problem of the limited doubling capacity of adult stem cells from teeth might be as simple as freezing them in liquid nitrogen, as was currently done with IVF embryos.

Morris said the Hanson had lodged patents on a variety of clinical applications for tooth-derived adult stem cells.