Scientists grew new teeth in lab

Although any application to humans is years away, the team hopes the new approach could eventually lead to the regeneration of entire organs in the lab.

Bioengeered organs are still in the earliest stage of development. Last year, Anthony Atala of Wake Forest University Medical School in Winston-Salem, North Carolina, and his colleagues transplanted some lab-grown bladders into human patients, a first for a discrete, complex organ. Efforts to grow working teeth, however, have met with difficulty.

In the new study, tissue engineer Takashi Tsuji of Tokyo University and colleagues started with separate populations of the two cell types that make teeth: epithelial cells and mesenchymal cells. Isolating the two types from the tooth germ--the nascent tooth tissue that hasn't erupted from the gum--of a mouse embryo, the researchers expanded each cell population to 105 cells each. They then injected both populations into a drop of collagen.