Amongst the varied practical applications of tissue engineering presently under development, growing replacement teeth has consistantly been near the front of the pack. Given the lower levels of risk involved in working on less vital structures such as teeth and hair, it wouldn't be surprising to see these medical applications of stem cells and tissue engineering brought to widespread clinical use in advance of heart and nerve regeneration.

In any case, here is another step forward towards those shiny new teeth you've been waiting for, grown from your own stem cells:

Fully functioning teeth have been grown from stem cells planted in the mouths of mice, scientists said today.

If you head over to PNAS, you'll find that the paper is open access and the full PDF is available:

The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging. Here, we report a successful fully functioning tooth replacement in an adult mouse achieved through the transplantation of bioengineered tooth germ into the alveolar bone in the lost tooth region. We propose this technology as a model for future organ replacement therapies. The bioengineered tooth, which was erupted and occluded, had the correct tooth structure, hardness of mineralized tissues for mastication, and response to noxious stimulations such as mechanical stress and pain in cooperation with other oral and maxillofacial tissues.

Much of this paper is concerned with establishing that, yes, this tooth is functionally sound and fully integrated with surrounding bone, tissue, and nerves - which is a big deal. It's all too easy to envisage techniques of tissue engineering that fail for one reason or another to generate the correct form of large-scale tissue growth. Japanese research groups have been turning out a number of interesting and important advances in past years, and here they've managed it again.