A bio-engineered germ of a tooth placed in the jaw of a mouse (top) buds through the gum at 36 days (center) reaching the size and alignment with opposing teeth for proper chewing after 49 days (bottom).
The teeth function like the real thing – roots, inner pulp, and outer enamel as hard as normal teeth.
Continuing to gain control over details, cell biologist Takashi Tsuji of Tokyo University of Science says the crown widths, cusp positions, and tooth patterning were not yet quite normal.