Teeth are something the human body can’t build again, but researchers in Japan have found a way to grow them successfully in mice.

Teeth grow from teeth germs, but humans only have a limited amount. Researchers from the RIKEN Center for Developmental Biology set out to discover if it was possible to grow more than one tooth from a single germ.

Teeth germs were taken from mice and grown.  After 14.5 days the germs were split into two using a nylon noose (below) in the hope, according to the team: “that signalling centers—which control the wave of molecules that regulate the development of the tooth—would arise in each part.”

Photo credit: RIKEN

The experiment was successful. The split germs created two teeth, which the team (including staff from the Tokyo Medical and Dental University) transplanted into the jaw of mice.

They successfully grew to be about half the size of standard teeth (below), with half the crowns, but permitted the mice to eat and respond to stimulus.

X-ray of mouse mouth with implanted teeth growing

The team found the newly grown teeth worked with orthodontic devices, such as braces – adjusting and moving like regular teeth.

The technique could help the one in ten people born missing a tooth or with teeth that aren’t properly developed, who currently rely on false teeth and implants, according to team leader Takashi Tsuji

“Our method could be used for paediatric patients who have not properly developed teeth as a result of conditions such as cleft lip or Down’s syndrome, since the germs of permanent teeth or wisdom teeth could be split and implanted.

“In the future, we could also consider using stem cells to grow more germs, but today there are barriers to culturing such cells, which will need to be overcome” he said.