The Scientists Trying to Make Regrown Teeth a Reality
Biochemist Hannele Ruohola-Baker says she receives emails almost daily from strangers pleading to take part in experimental dentistry — not routine fillings, but attempts to regrow their teeth entirely.
Ruohola-Baker, associate director of the University of Washington’s Institute for Stem Cell and Regenerative Medicine, is part of a growing field applying regenerative medicine to tooth loss, a problem that affects millions. The appeal goes beyond novelty. Teeth matter more to overall health than many assume: bacteria from gum disease has been linked to heart disease, respiratory infections and even Alzheimer’s, while tooth loss is associated with higher rates of illness, earlier death, and knock-on effects on eating and emotional wellbeing. “Oral health is key to good systemic health,” says Pamela Yelick of Tufts School of Dental Medicine, who describes teeth as “your window to the world.”
Current treatments — fillings, crowns, implants — mostly patch damage rather than restoring biological function, lasting between five and twenty years before needing repeated repairs. “Regenerative dentistry can be a paradigm shift,” says Anne George, a professor of oral biology at the University of Illinois, Chicago. “It emphasises healing.”
Regrowing enamel and dentine
Much of the research targets cavities, which George calls “the most common thing that destroys the tooth.” They form when bacteria feed on sugar and produce acid that eats through enamel, exposing the softer dentine layer beneath. George studies the proteins involved in dentine growth and helped clone a gene that builds it, work she hopes could one day let damaged teeth repair cavities on their own.
Ruohola-Baker’s lab is pursuing “living fillings” built from enamel-producing cells called ameloblasts, which normally die off once a tooth erupts. By chemically coaxing stem cells into becoming ameloblasts and odontoblasts — the cells that build dentine — her team created a tooth organoid that secretes enamel proteins on its own, a step toward her ultimate goal: embedding cells that let a whole tooth grow inside a patient’s mouth.
For more extensively decayed teeth, dentists typically turn to implants, but these come with drawbacks — no nerves to prevent biting too hard, risk of bacterial infection, and artificial crowns that need replacing roughly every 15 years at a cost of thousands of dollars. Ana Angelova Volponi, director of regenerative dentistry at King’s College London, is developing an organoid that could replace implants altogether. “Rather than just trying to patch what has been damaged, we could use a biological replacement,” she says. Her team has combined adult human gum cells with tooth-forming cells from mice to grow a hybrid structure with developing roots.
Humans, unlike sharks — which regenerate teeth continuously — or elephants and kangaroos, which get extra sets of molars, cannot naturally regrow adult teeth. But pigs offer an unlikely shortcut: their jaws hold multiple unerupted tooth buds. Using cells from discarded pig jaws combined with human dentine- and enamel-forming cells on a bioengineered scaffold, Yelick’s team grew tooth-like structures in minipigs within three months, at a pace close to natural pig tooth development. “It was a proof of principle that this could really work,” she says, adding she’s now working toward prompting tooth growth directly inside a jaw, eventually without pig cells at all.
Despite the interest, lab-grown teeth remain years away from patients. Experiments in non-human primates must come first, says Ruohola-Baker, requiring further time, funding and improved conditions for tooth development in the lab. Still, researchers believe the underlying lessons could help regenerate other tissue, including organs and bones. “That’s where I see the future,” says Volponi. “It’s not very clear, but it’s hopeful.”
Source: BBC News