The question of whether adults can grow new teeth is common, and the direct answer is no, not through any natural biological process. Unlike reptiles or fish that can replace teeth throughout their lives, humans are biologically programmed to have only two sets of teeth. Once the second set is lost, the body does not initiate a replacement. However, this biological limitation is being challenged by advancements in regenerative medicine, with researchers developing methods to unlock the body’s latent potential to grow a third set of functional teeth.
The Biology of Two Sets of Teeth
Humans are classified as diphyodonts, meaning they develop only two successive sets of teeth: 20 primary (deciduous) teeth and 32 permanent teeth. This limitation traces back to the embryonic structure responsible for forming teeth, known as the dental lamina. The dental lamina is a band of epithelial tissue that gives rise to both the primary and permanent tooth buds.
After the permanent teeth erupt during childhood and adolescence, the dental lamina typically disintegrates and becomes inactive, exhausting its potential to form subsequent teeth. This biological mechanism is a trade-off in mammalian evolution, favoring a more complex, durable, and specialized set of teeth. Human genetics have historically capped the number of dentitions at two, leaving no natural blueprint for an adult to regenerate a lost tooth.
Modern Non-Biological Replacement Options
Because the body cannot naturally replace a permanent tooth, the current standard of care relies on non-biological prosthetic solutions to restore function and appearance. The most stable option is the dental implant, which involves surgically placing a titanium post into the jawbone to serve as an artificial root for a porcelain crown. This method prevents bone loss and functions most like a natural tooth.
Other established options include dental bridges, which span the gap created by a missing tooth by anchoring a prosthetic tooth to crowns placed on adjacent natural teeth. For patients missing multiple teeth or an entire arch, removable partial or full dentures are a less invasive and often more affordable solution. These options are effective restorations, but they require maintenance and lack the biological integration of a natural tooth.
Research Breakthroughs in Growing New Teeth
The most significant recent progress in regenerative dentistry involves activating the body’s dormant potential to grow new teeth. Researchers are focusing on molecular signaling pathways that regulate tooth development, identifying proteins that act as natural inhibitors. A key target is the protein Uterine Sensitization Associated Gene-1 (USAG-1), which suppresses tooth development by antagonizing signaling molecules like Bone Morphogenetic Protein (BMP) and Wnt.
Scientists have successfully developed a neutralizing antibody that blocks the function of USAG-1, restarting the tooth-growing process in animal models like mice and ferrets. This molecular therapy aims to awaken residual or dormant tooth buds in the jaw, leading to the growth of a third set of teeth. This drug-based approach is promising because it is a cell-free therapy, relying on stimulating the body’s existing potential rather than requiring complex tissue engineering.
What the Future Holds for Tooth Regeneration
The USAG-1 research has moved from animal studies to human clinical trials. The initial Phase 1 trials, which began in late 2024 in Japan, are focused on assessing the safety and tolerability of the drug in adult patients with missing teeth. If these safety trials prove successful, subsequent phases will focus on efficacy, particularly targeting children with congenital anodontia—a condition where patients are born missing multiple permanent teeth.
The goal is to transition this molecular therapy into a widely available treatment option, with researchers projecting availability as early as 2030. Successful clinical application would represent a significant shift in oral healthcare, offering a biological and permanent solution that avoids the need for artificial materials like titanium implants or dentures. This research promises a future where losing a permanent tooth can be remedied by stimulating the body’s own restorative capabilities.