I cant think of any reason to use stem cells from urine to grow teeth. Urine is generally considered sterile so the number of any type of cell is low. Interestingly I worked on a project that involved isolating adult stem cells from human fat tissue. There are ~ 1000x more stem cells in fat than in blood. The cells were used in reconstructive surgery for mastectomy patients.
So, they’re just pissing in the wind?............