Instead of artificial implants, patients may receive lab-grown tooth replacements. Credit: Deposit Photos Get the Popular Science daily newsletter💡 Researchers are closing in on a breakthrough that could one day change one of dentistry’s most common practices: fillings. Building off work published late last year in ACS Macro Letters, a team at King’s College London is developing methods for lab-grown replacement teeth and fillings made from human cells. Humanity has endured the pain of cavities for as long as we’ve had teeth, but the basic remedy has remained fundamentally the same for millennia. Evidence dating at least as far back as 13,000 years ago indicates Paleolithic peoples made fillings from a combination of bitumen, plant fibers, and even hair to adhere to a tooth’s inner walls. Around 6,500 years ago, remedies in present-day Slovenia involved beeswax fillings, while Pliny the Elder referenced similar procedures in his Naturalis Historia (shortly before his untimely demise during the Mount Vesuvius eruption of 79 CE). Today’s dental fillings can be composed of multiple synthetic materials like alloys, amalgams, and composite resins. But at the end of the day, a filling is a filling—and they can still pose problems. Xuechen Zhang examines teeth cells on a computer during research into growing replacements from stem cells. Credit: King’s College London “Fillings aren’t the best solution for [repairing] teeth. Over time, they will weaken tooth structure, have a limited lifespan, and can lead to further decay or sensitivity,” Xuechen Zhang said in an April 14 university profile. More intensive therapies like implants can also add further complications, and require a precisely crafted prosthetics to attach to the alveolar bone. Zhang and fellow researchers have spent years attempting to grow human teeth in the lab using organoids, but routinely hit a wall when trying to direct cells to communicate with one another. Without the ability to “tell” one another that they need to form into tooth cells, the organoids simply couldn’t grow from there. However, Zhang’s team discovered a solution after collaborating with experts at nearby Imperial College. The problem was that their target cells previously attempted to send signals all at once, as if they were simultaneously shouting over one another. By suspending mouse cells in specialized three-dimensional matrices made with modified hydrogels, the cells paced their signal releases and properly communicated tooth production plans. “This new material releases signals slowly over time, replicating what happens in the body,” explained Zhang. Now that it’s possible to create teeth from bioengineered mouse stem cells, researchers are moving on to investigating the best methods to get future human versions into mouths. In the case of whole tooth replacement, options may include transplanting young cells from a lab culture directly into the space where it was, then fostering them to grow into an entirely new tooth. Another possibility may be to grow an entire tooth in the laboratory, then treating it like a natural implant once it is ready.  “Lab-grown teeth would naturally regenerate, integrating into the jaw as real teeth,” said Zhang. “They would be stronger, longer lasting, and free from rejection risks, offering a more durable and biologically compatible solution than fillings or implants.”