Humanlike teeth have been grown in pigs
Toothlike structures represent a step toward bioengineered replacements for dental implants, say researchers.
Scientists are working on lab-grown human teeth. Pamela Yelick and Weibo Zhang at Tufts University School of Dental Medicine in Boston have grown a mixture of pig and human tooth cells in pieces of pig teeth to create bioengineered structures that resemble real human teeth.
“It’s very difficult to replace an implant, because first you have to rebuild all the bone that has been absorbed over time that’s gone away,” said Yelick. For the last few decades, she has been working to create more humanlike tooth substitutes, using cells taken from real teeth and grown in the lab into toothlike structures. “We’re working on trying to create functional replacement teeth,” she said.
For her research, Yelick uses cells from pig jaws. Pigs grow multiple sets of teeth throughout their lives, so the jawbones contain cells from underdeveloped teeth that have not yet broken through the gums. Yelick and Zhang collect cells from these teeth and coax them in the lab to grow and multiply until they have “tens of millions” of cells.
In previous experiments, Yelick and colleagues have seeded these cells onto ‘scaffolds’—biodegradable tooth-shaped structures – and implanted them into rats. She and her colleagues found that once they were inside a living body, the cells would start to organize themselves into toothlike structures. “They were small, but their morphology was identical to that of naturally forming teeth,” said Yelick.
Since then, she and her colleagues have been working toward growing human teeth in the lab. In their latest research, Yelick and Zhang used cells from donated human teeth. And to create a more ‘natural’ scaffold, the team stripped away the cells from the teeth of mini pigs.
Then, in an approach similar to the one Yelick had used before, they grew a mixture of pig and human tooth cells inside scaffolds created from pieces of pig teeth. After a few weeks in a lab dish, the tooth fragments were implanted into the jaws of six mini pigs.
Two months later, the team removed the teeth to see how they were doing. They found that they had started to grow in a similar way to healthy adult teeth. They even developed hard layers of cementum and dentin. “They’re very toothlike,” saidYelick, who published the work in the journal Stem Cells Translational Medicine.