It's a scientific feat equal parts fascinating and stomach-turning: Scientists have been able to grow "rudimentary teeth" from urine, reports the BBC. Suspend your disbelief, and read on: The Chinese team's process, as outlined in Cell Regeneration Journal, had researchers harvest cells from urine and then convert them into stem cells; these were combined with material from a mouse and transferred into the creature. Three weeks later, a tooth-like structure began to emerge: It "contained dental pulp, dentin, enamel space, and enamel organ," the researchers say.
"The final dream of total regeneration of human teeth" is still a distant prospect, they caution. One hurdle: The "teeth" they grew were not as hard as our teeth, perhaps because they weren't used as they developed, reports the New Scientist. And that's not the only issue. Among the others: figuring out how to grow a specific size and shape. "It doesn't take a genius to figure out there's a big difference between an incisor and a molar tooth," says one researcher in the field of regenerative dental medicine. And then there's that urine. A British stem cell scientist calls it "probably one of the worst sources" of stem cells, due to the relative dearth of cells in it and the increased contamination risk. Countered the study's head researcher, "This is the most convenient source." (Click for another wild scientific breakthrough involving mice.)