Pigs can regenerate adult teeth. What if humans could do it?

When a child loses a baby’s teeth, there is a set of adults already growing under the gum, ready to appear. However, if you lose your permanent teeth, you won’t be waiting any longer on the wing. Currently, the options for replacing these missing teeth are either dentures or titanium implants, and neither of them provide the same functionality and feedback as actual living teeth.

Pamela Yelick, professor at Tufts University Dental Medicine, hopes to be able to grow new living teeth to replace what we have lost. In a paper published in Stem Cell Translation Medicine at the end of 2024, Eric and her colleagues showed that a combination of human-pig tooth cells can be used to raise pig human-like teeth. This task is an important step in replacing dental implants with bioengineered living teeth.

Dental implants usually have a titanium base and are fixed to the jawbone. Titanium integrates well with bone, but the soft tissue surrounding the natural roots of teeth does not promote nerves that cushion chewing forces, promoting healthy bone turnover or providing sensory feedback.

If the implant is not fully aligned or if a person is biting too much, the bones around the implant begin to break and are absorbed by the body. This creates an opportunity for bacteria to reach the implant, accelerate bone resorption, and ultimately the implant may fail.

“Even creating a root of a tooth that can be applied with an artificial crown can be placed in the middle of the tooth, which is secured by the periodontal ligaments, rather than being screwed into the jaw, can also significantly improve the person’s oral health and systemic health.

It’s not easy to encourage your body to grow new teeth. Our teeth begin as tooth buds, small bulbs of cells inside the jaw. This separates and grows into all the hard, soft tissue that makes up the teeth and connects to the jaw. Researchers had to create their own bioengineered tooth buds with the appropriate cell types and instructions to grow into the teeth on their own.

Tooth buds are made of two types of cells: epithelial cells and dental leaf cell cells that produce tooth enamel, and eventually form the remaining teeth, including the pulp, dentin, cementum and periodontal ligament tissue.

Yelick and her team were able to collect dental mesenchymal cells from the extracted human wisdom teeth and other healthy teeth pulp removed for orthodontic reasons, but epithelial cells of teeth are present only at very early stages of tooth development. Once our teeth are formed, they cannot be collected from people. However, they can be collected from unblocked teeth present in pig jaws.

Unlike humans, pigs can grow multiple sets of adult teeth, so the adult jaw contains additional tooth buds. Researchers acquired pig jaws that would otherwise have been dumped from the slaughterhouse and could have extracted tooth buds from them. They cultured these dental and human tooth cells in the lab and then added them to a bioengineering scaffold that helps provide the necessary clues to initiate tooth development. They then implanted these bioengineered tooth buds into the jaws of adult pigs and monitored the animals for several months.

Researchers found that bioengineering teeth developed at similar rates as natural pig teeth. This is pretty similar to that of human teeth. The experiment was only planned for three months, so the teeth had no chance to appear through the gums, but they had the same developmental stage as natural teeth.

“We’ve found out we can make these beautiful little teeth,” says Yelick. “They are still in their jaws – they haven’t erupted yet, but they look like natural human teeth.”

Yelick and her colleagues hope to follow dental development for a long period of time in future experiments. They are also investigating signaling molecules that direct the behavior of cells, looking for ways to start growing teeth from within the jaw, rather than having to individually extract and culture cells in the lab.

Their ultimate goal is to promote cells within a person’s jaw and to raise new, fully human teeth. No pig cells are needed. While researchers need to do more work before they can grow a living alternative to human teeth, Yelick believes it will be achievable over the next decade.

“Ideally, you’ll keep your teeth as long as possible. That’s the best scenario,” says Yelick. “But if something happens, I hope we can get access to biological dental alternatives.”