Can Stem Cells Regrow Teeth? Here’s What the Science Says

Stem cells cannot yet regrow a fully functional human tooth from scratch, but they have already regenerated living dental pulp, and several research paths are converging on whole-tooth regeneration within the next decade or two. The gap between today’s titanium implants and a truly biological replacement tooth is still wide, yet it has been closing faster than most people realize. A Japanese team’s antibody-based approach recently moved into human trials, and earlier clinical work has already shown that transplanted dental stem cells can rebuild the soft tissue inside an injured tooth, complete with blood vessels and nerves.

Why Humans Cannot Simply Grow a Third Set

Most mammals, including humans, are diphyodonts: we get two sets of teeth and no more. Reptiles like crocodilians and some fish replace teeth continuously throughout life, a trait called polyphyodonty. The difference comes down to a thin ribbon of tissue called the dental lamina. In species that keep replacing teeth, the dental lamina persists as a permanent, active structure. In humans and other diphyodonts, that lamina fragments and regresses shortly after the second set of teeth begins forming. Once it’s gone, the biological machinery for initiating new teeth is effectively dismantled.¹

This is not a random accident of evolution. Ever-growing or continuously replaced teeth have appeared independently in many mammalian lineages over the past 65 million years, often linked to increasingly abrasive diets. The developmental trick behind these adaptations involves maintaining a stem cell niche that feeds new tooth tissue throughout an animal’s life. Humans lost that niche in exchange for a precisely sized, stable dentition suited to an omnivorous diet. Researchers studying these evolutionary patterns are essentially trying to figure out which molecular switches got turned off, and whether any of them can be turned back on.

The Stem Cells Already Hiding in Your Mouth

One of the more surprising discoveries of the early 2000s was that teeth themselves harbor stem cells. The soft pulp tissue inside every tooth contains dental pulp stem cells (DPSCs), which can differentiate into the specialized cells that produce dentin, the hard tissue making up most of a tooth’s structure. Beyond the pulp, the periodontal ligament, the thin tissue anchoring teeth to the jawbone, contains its own stem cell population (PDLSCs) capable of regenerating the supporting structures around teeth.²

Perhaps the most accessible source turned out to be baby teeth. In 2003, researchers demonstrated that the pulp of shed baby teeth contains a population of highly proliferative stem cells (called SHED) capable of generating dentin and bone after transplantation into mice.³ These cells are easier to collect than bone marrow and don’t raise the ethical issues associated with embryonic stem cells. They’ve since become a workhorse in dental regeneration research, with studies exploring how growth factors can boost their ability to form mineralized tissue and collagen.⁴

Each of these stem cell types is best suited to regenerating specific parts of a tooth. DPSCs excel at rebuilding the inner pulp and dentin. PDLSCs are better candidates for restoring the periodontal ligament and the cementum layer that coats the root surface.⁵ Regenerating a complete tooth means coordinating all of these cell types in the right spatial arrangement, which is one reason whole-tooth regeneration has proved far harder than regenerating individual tissue layers.

The Antibody That Grows Extra Teeth in Mice

A different strategy sidesteps stem cell transplants altogether by trying to coax the body into growing teeth on its own. A team at Kyoto University focused on a protein called USAG-1, which normally acts as a brake on tooth development by blocking signals from bone morphogenetic proteins (BMPs). When mice are genetically engineered to lack USAG-1, they develop supernumerary teeth, essentially extra teeth that grow from dormant tooth germs the body would normally suppress.⁶

Building on that finding, the researchers developed an antibody that blocks USAG-1 without requiring genetic modification. When administered to mice with congenital tooth agenesis (a condition where certain teeth never develop), the antibody restored tooth formation by relieving the molecular brake on dormant tooth germs.⁷ The approach also worked in mouse models involving different genetic causes of missing teeth, suggesting it targets a fundamental control mechanism rather than one narrow pathway.⁸

This is the approach that has generated the most headlines recently. The team behind it launched a human clinical trial in 2024 targeting patients with congenital tooth agenesis, starting with adults who are missing at least one tooth from birth. If the antibody proves safe and effective in that population, trials would presumably expand to acquired tooth loss. But the jump from genetic tooth agenesis (where dormant tooth germs may still exist) to age-related or trauma-related tooth loss (where no tooth germs remain) is a significant biological leap that the antibody may not be able to make on its own.

What Has Already Worked in Human Patients

While whole-tooth regeneration remains experimental, dental pulp regeneration using stem cells has already been tested in people. The most prominent trial, published in 2018, enrolled 40 children and young adults with traumatized permanent incisors. Thirty received implantations of stem cells harvested from their own baby teeth, while ten received conventional treatment. After twelve months, the stem cell group showed regeneration of three-dimensional pulp tissue with functional blood vessels and sensory nerves. Their tooth roots continued to grow significantly longer, and the openings at the root tips narrowed, signs of ongoing healthy development. Twenty patients followed for 24 months showed no adverse events.⁹

A separate pilot study transplanted dental pulp stem cells into five adults with inflamed pulp tissue. At four weeks, the treated teeth responded positively to electric pulp testing, meaning the nerves were functional. Imaging at 24 weeks showed the regenerated tissue inside the root canal had a signal similar to normal dental pulp, and three of the five patients developed new functional dentin.¹⁰

These trials are small, and they regenerated pulp inside existing tooth shells rather than growing new teeth. But they proved something fundamental: transplanted dental stem cells can generate living, innervated, vascularized tissue inside a human tooth. That is the necessary first step on the way to growing teeth from scratch.

Scaffolds and Bio-Roots

Growing tissue in the right shape requires more than just the right cells. Researchers use scaffolds, three-dimensional structures made of biocompatible materials, to guide cell growth into tooth-like forms. In laboratory settings, 3D-printed scaffolds made from materials like alginate-gelatin hydrogels have promoted dental pulp stem cells to form mineralized, bone-like nodules and express the genes associated with dentin production.¹¹

Animal experiments have taken the scaffold concept further. In one study, dental pulp stem cells were seeded onto 3D-printed hydroxyapatite/polylactic acid scaffolds and transplanted into the jaws of adult dogs. The scaffolds loaded with cells showed significantly more mineralization than scaffolds implanted without cells, confirming that the stem cells actively contribute to building hard tissue rather than just hitching a ride on the scaffold material.¹²

The bio-root concept merges stem cells and scaffolds to produce a biological tooth root that can be topped with a prosthetic crown. In one animal study, bio-roots were compared head-to-head with conventional titanium implants three months after crown placement. Functionally, the bio-root performed equivalently to the implant. Biomechanically, the bio-root more closely resembled a natural tooth root in compressive strength and flexibility, though the titanium implant was stiffer and stronger on those same measures.¹³ That flexibility is actually a feature: natural teeth flex slightly under biting force thanks to the periodontal ligament, which distributes stress and sends sensory feedback to the brain. Titanium implants lack that ligament entirely, which is why biting on an implant feels different from biting on a real tooth.

Getting Nerves and Blood Vessels Into the Picture

A regenerated tooth without nerve supply would be a biological dead end. Innervation is what lets a tooth detect temperature, pressure, and pain, protective signals that prevent you from biting too hard or ignoring an infection. Regrowing that nerve supply is one of the harder problems in tooth regeneration because the nerves need to find their way from the trigeminal ganglion in the skull into the narrow root canal of the new tooth.

In a mouse model, researchers tested nanostructured scaffolds loaded with cyclosporine A (an immunosuppressive drug that also promotes nerve growth) and found that nearly 90% of regenerated teeth developed innervation, with nerve fibers penetrating into the newly formed dental tissue.¹⁴ The human pulp regeneration trials described earlier also demonstrated sensory nerve recovery, but in those cases the nerves were regrowing into an existing root canal rather than a de novo structure. Achieving the same result in a whole tooth grown from cells and scaffolds will be considerably more demanding.

The Shape Problem

Even when researchers successfully grow tooth-like structures in animals, those structures often come out the wrong size or shape. Bioengineered teeth produced from mouse tooth germ cells using a technique called the organ germ method have been significantly smaller than natural teeth and exhibit abnormal crown shapes.¹⁵ A molar that is the wrong width or a canine with the wrong cusp pattern would cause bite problems, so shape control is not a cosmetic concern but a functional one.

The difficulty traces back to how natural teeth get their shape. Tooth development relies on an ongoing conversation between two tissue types: epithelium and mesenchyme. These two layers exchange molecular signals that determine everything from where a tooth forms to how many cusps it has and how thick its enamel will be.¹⁶ Recreating that conversation in a lab dish or scaffold, where the spatial cues of the jaw are absent, is an unsolved engineering problem. Some groups are exploring growth factors that can nudge bioengineered teeth toward normal proportions, but reliable shape control remains years away.

Safety Concerns That Slow the Process

The enthusiasm around dental stem cells is tempered by real safety issues. When working with embryonic stem cells or induced pluripotent stem cells (cells reprogrammed from adult tissue to behave like embryonic ones), there is a risk of teratoma formation, meaning the cells could produce unwanted tissue types, including tumors. Adult dental stem cells like DPSCs and SHED carry a lower risk on this front, but prolonged culture outside the body or genetic manipulation of cells introduces the possibility of cancerous mutations.¹⁷

Beyond tumor risk, the practical challenges are formidable. Cells grown outside the body need to be kept sterile, stored at precise temperatures, shipped without degradation, and transplanted in a clinical setting equipped for cell therapy. Each of these steps introduces a potential failure point. And all of this must happen within a regulatory framework designed for pharmaceutical products, which means years of safety testing before any new therapy can reach the general public.¹⁸

Cost, Regulation, and the Road to the Dentist’s Chair

Even if the science delivers a working method for growing teeth, getting it into routine clinical use involves obstacles that have nothing to do with biology. Producing patient-specific stem cells is expensive and time-consuming. One proposed solution is allogenic banking, essentially building stockpiles of tissue-typed dental stem cell lines from donated pulp, so that a patient could receive pre-prepared cells from a compatible donor rather than waiting weeks for their own cells to be cultured.¹⁹ Several private companies already offer to bank stem cells from children’s baby teeth, though the clinical applications remain largely hypothetical at this point.

Regulatory pathways add years to the timeline. Stem cell therapies and antibody drugs fall under the category of advanced therapy medicinal products (ATMPs) in most countries, which means they face a more demanding approval process than conventional drugs or medical devices. The anti-USAG-1 antibody trial in Japan benefits from that country’s relatively streamlined regulatory approach to regenerative medicine, but approval in the U.S. or Europe would involve separate, potentially longer processes.

Then there is the knowledge gap among the dentists who would eventually deliver these treatments. In a survey of practicing dentists, the most commonly cited barriers to adopting stem cell therapies were lack of knowledge (cited by about 44%), cost (about 26%), and ethical concerns (about 15%).²⁰ Even a proven treatment would face slow adoption if the professionals delivering it don’t feel confident using it.

Rebuilding Gums and Supporting Tissue

Much of the public conversation focuses on regrowing the tooth itself, but periodontal disease, which destroys the gums, ligament, and bone supporting the teeth, is the leading cause of tooth loss in adults. Regenerating these supporting structures is arguably a more immediate clinical need than growing whole teeth, and the science is further along.

Periodontal ligament stem cells have been shown to regenerate the ligament tissue itself and, when combined with growth factors like BMP-2 and BMP-7, to lay down new cementum on exposed root surfaces in animal models. In one study, scaffolds releasing BMP-7 produced a new cementum-like mineralized layer on dentin that expressed a protein specific to natural cementum, suggesting the regenerated tissue was biologically authentic, not just a mineral deposit.²¹ If this kind of targeted periodontal regeneration reaches the clinic before whole-tooth regeneration does, it could save millions of teeth that would otherwise be extracted.

Why Tooth Loss Matters More Than People Think

The drive behind all of this research is not just academic. Tooth loss affects people in ways that go well beyond chewing. A longitudinal study of implant patients found significant improvements not just in how people rated their teeth, but in their facial and overall body image after receiving replacements for missing teeth.²² Qualitative research paints an even starker picture: for some individuals, losing teeth was experienced as a profound disruption to their sense of self, bound up with feelings about aging and bodily integrity. Wearing dentures introduced a new source of anxiety, the sense of living with an unreliable, foreign object in the mouth.²³

Titanium implants have been transformative for millions of people, but they remain inert hardware. They do not flex like a natural tooth, they cannot sense temperature or pressure, and they require healthy jawbone to anchor into, which many elderly or medically compromised patients lack. A biologically regenerated tooth, one with living pulp, a functional ligament, and sensory innervation, would eliminate nearly all of those limitations. That is why this research, despite being years from your dentist’s chair, generates so much interest.

The Difference Between Regeneration and Repair

It helps to be clear about what the different research programs are actually trying to do, because “regrowing teeth” covers a spectrum of ambitions. At the most conservative end, dental pulp regeneration aims to save existing teeth by rebuilding the living tissue inside them. This is closest to the clinic and has already been demonstrated in small human trials. Periodontal regeneration targets the tissues around the tooth, potentially rescuing teeth loosened by gum disease. Bio-roots aim to produce a living root that can support a prosthetic crown, offering a biological alternative to a titanium post. And whole-tooth regeneration, the most ambitious goal, would grow a complete tooth from cells and implant it into an empty socket.

Each step up in ambition requires solving new problems. Pulp regeneration works inside the protected shell of an existing tooth. A bio-root needs to generate mineralized tissue, anchor into bone, and develop a periodontal ligament. A whole tooth additionally needs enamel-forming cells (ameloblasts), correct morphology, eruption into the mouth, and integration with the nerve and blood supply. The field is advancing on all of these fronts, but not at the same pace. The reader who sees a headline about “regrowing teeth” should ask which part of the tooth is being discussed before getting too excited, or too skeptical.