Test-Tube Teeth

Scientists are connecting stem cells to create the tooth buds that form in the early embryo. The idea is to implant these "primordial teeth" (that are in their early stage) into human jaws and let the cells take it from there. By using a patient's own stem cells avoids the problems that often happen in ordinary transplants.

Teeth form from just two cell types in the embryo, epithelial cells and mesenchymal cells. The epithelium becomes enamel on the outside, and the mesenchyme forms the connective tissue and blood vessels inside. Tooth development involves an elaborate network of thousands of genes. The researchers have learnt which are most important genes in the control of size and shape. Some genes only work in the upper jaw, others only where molars grow.

In one experiment, Sharpe's team (from King’s College London) took early tooth buds from growing embryos and switched on a gene known to be active in growing molars. They implanted the buds in the front of the jaws of mice, where incisors would normally grow. However, they emerged with molars in front and back. Sharpe then turned this gene on artificially and transformed the way a tooth develops. Sharpe's team took tooth buds forming in a mouse embryo and replaced the mesenchyme with stem cells taken from an adult mouse, to see whether they could use stem cells. Stem cells can be pushed to convert into almost any tissue in the laboratory, when given the right signals. The stem cells were changed into tooth tissue when they were implanted into a mouse kidney, where the blood supply provides enough oxygen to get a complete tooth. For this Sharpe concentrated on adult stem cells, because eventually for human patients, doctors don't want to be extracting embryonic stem cells. (The advantage of using adult stem cells to regenerate human teeth is that the cells will come from the patient.) By the positive results he achieved, it appears that the adult mouth can provide a suitable environment for tooth development. However there is more research ad investigation to be made to complete this for human bioengineered teeth.

• The advancement is unlikely to be controversial as it is not against nature and will be advantageous for people who need new teeth.

• This advancement will benefit people who need new teeth and also has two other particular advantages: teeth are easily accessible and our quality of life is greatly improved if we have them, however, we don’t need our teeth to live. Someday, this may mean the end of crowns and dentures. It could also mean an end to the endless suffering, caused by tooth loss worldwide. Therefore, the advancement is likely to have a positive affect on our everyday life.