seen. Teeth present a unique challenge for researchers because the stem cells must be stimulated to grow the right balance of hard tissue, dentin and enamel , while producing the correct size and shape." Link: http://singularityhub.com/2012/05/10/toothless-no-more-researchers-using-stem-cells-to-grow-new-teeth/ 10 May 2012 Learning from the Regrowth of Feathers and Hair? Permalink | View Comments