The ultimate goal of this research is to replace teeth lost through injury or ageing with those grown from a person’s own cells.
A team from the Guangzhou Institute of Biomedicine and Health in China isolated cells normally found in human urine, that have been shed from the lining of the urinary tract. These cells were induced to become pluripotent stem cells, and stimulated to develop into an epithelium, which would make up the surface of the tooth. They were then combined with early-stage dental cells from mice, mesenchymal cells, that have the capacity to develop into the dental pulp in the middle of the tooth.
The resulting bundles of cells were transplanted into the kidneys of other mice and, after three weeks, about one third of them had grown into tooth-like structures containing dental pulp, dentin and enamel.
The researchers said that their work, along with future studies stimulating human cells into forming the dental pulp as well as the epithelium, would lead to 'the final dream of total regeneration of human teeth for clinical therapy'.
The advantage of using urine as a source of stem cells is that it is very easily accessible, unlike alternatives such as bone marrow. However, Professor Chris Mason, a stem cell scientist at University College London, told the BBC that he was sceptical about using urine as a source of stem cells. '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 also noted that 'the big challenge' in growing cells in the lab is that 'the teeth have got a pulp with nerve and blood vessels which have to make sure they integrate to get permanent teeth'.
The research was published in the journal Cell Regeneration.