London: Stem cells obtained from urine could one day allow humans to regrow lost teeth, scientists claim.
Chinese scientists used stem cells from urine to create tiny 'tooth buds' that when transplanted into mice grew into tooth-like structures.
Stem cells - cells which can grow into any type of tissue - are popular among researchers looking for ways to grow new teeth to replace those lost with age and poor dental hygiene.
The group at the Guangzhou Institutes of Biomedicine and Health used urine as the starting point, 'BBC News' reported.
Cells which are normally passed from the body, such as those from the lining of the body's waterworks, are harvested in the laboratory. These collected cells are then coaxed into becoming stem cells.
In the study, a mix of these cells and other material from a mouse was implanted into the animals. The researchers said that after three weeks the bundle of cells started to resemble a tooth: "The tooth-like structure contained dental pulp, dentin, enamel space and enamel organ."
However, the "teeth" were not as hard as natural teeth.
The research is not immediately going to lead to new options for the dentist, but researchers said it could lead to further studies towards "the final dream of total regeneration of human teeth for clinical therapy".
However, experts caution the goal faces many challenges. Professor Chris Mason, a stem cell scientist at University College London, said urine was a poor starting point.
"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. You just wouldn't do it in this way," he said.
He also warned that the risk of contamination, such as through bacteria, was much higher than with other sources of cells. The study was published in Cell Regeneration Journal.