Chinese scientists used human urine to grow rudimentary teeth in a laboratory, according to a new study published in the Cell Regeneration Journal.
While the teeth are rudimentary and the technique used to grow them is unappealing, researchers say it could one day be used as a way to replace teeth lost through aging or poor dental hygiene.
Researchers at Guangzhou Institute of Biomedicine and Health extracted cells contained in urine that would normally be passed from the body and managed to coax them into becoming stem cells.
Using urine to cultivate and coax stem cells within into teeth may also be less controversial than harvesting stem cells from human embryos, the researchers report.
A mix of the urine-derived stem cells and material from a mouse was implanted into laboratory mice. After three weeks of growth, the bundle of cells started to resemble a tooth and was composed of "dental pulp, dentin, enamel space and enamel organ," the BBC reported. However these teeth were not nearly as strong as natural teeth.
As such, the technique will be be used for dental enhancements any time soon, but the researchers report that their work could pave the way towards "the final dream of total regeneration of human teeth for clinical therapy."
But the research has its critics. Chris Mason, a stem cell scientist at University College London, told the BBC that urine was a poor choice for a stem cell source.
"It is probably one of the worst sources, there are very few cells in the first place and the efficiency of turning them into stem cells is very low," he told the BBC. "You just wouldn't do it in this way."
Mason also warned that the risk of bacterial contamination is higher with urine than it would be in other sources. He also added that the researchers face the challenge of integrating the tooth pulp with nerves and blood vessels in order to grow functional teeth.