You probably do not remember when you grew your very first tooth, but if you are a parent you certainly remember the first tooth of your child. This tooth, and for that matter, the whole baby, developed from a single cell, a stem cell.

We are so used to and are not that much in awe, that we, after the first baby teeth fall out, grow another set of teeth. Usually we just accept as a fact that that is the last set of teeth we ever grow. One characteristic of a good scientist is, that he tries to overcome accepted knowledge, and the fact that we grow two set of teeth and no more, is certainly a challenge for a good scientist.

That is particularly challenging as there are observable facts that bodies are able to repair pretty severe damages. Bones grow together, cuts heal and the lizard can even grow back a whole tail.

As the blue-print for the whole body is contained in every single cell of the body, why stop at two sets of teeth?

Great progress has been made in answering this questions and now researchers were successful in using stem cells to grow a replacement tooth for an adult mouse, the first time scientists have developed a fully functioning three-dimensional organ replacement, according to a report in the Proceedings of the National Academy of Sciences.

The researchers at the Tokyo University of Science created a set of cells that had the genetic instructions to build a tooth re-activated, and then implanted them into the mouse’s empty tooth socket. The tooth grew out of the socket and through the gums, as a natural tooth would. After eleven weeks the engineered tooth had matured. It had a similar shape, hardness and response to pain or stress as a natural tooth, and worked equally well for chewing. The researchers suggested that using similar techniques in humans could restore function to patients with organ failure.

Takashi Tsuji, PhD. Tokyo University of Science A ‘tooth germ’ implanted in a mouse’s jaw grew into a fully functioning tooth with the properties of a natural one.