A 2025 study from King’s College London found that keratin extracted from wool can guide the growth of an enamel-like mineral layer on damaged teeth, producing a coating that was substantially harder than the resin materials commonly used to treat early decay.
Tooth enamel is the hardest tissue in the human body, but once it is lost it does not regenerate. This has made enamel repair one of the central challenges in restorative dentistry. Fluoride can strengthen existing enamel and slow mineral loss, but it cannot rebuild the complex architecture of enamel after substantial erosion has occurred. When cavities develop, treatment usually involves removing decayed tissue and replacing it with synthetic materials such as composite resin or amalgam.
The need for better approaches is considerable. According to the World Health Organization, oral diseases affect approximately 3.7 billion people worldwide, and untreated dental caries in permanent teeth remains the most common health condition globally. The economic burden is also substantial, with hundreds of billions of dollars spent annually in treatment costs and lost productivity.
Before this study, researchers had already shown that proteins and peptides can direct the formation of enamel-like hydroxyapatite crystals under laboratory conditions. Investigators have used amelogenin-derived peptides, elastin-like recombinamers, and other biomimetic matrices to induce oriented crystal growth that resembles natural enamel. These approaches demonstrated that enamel regeneration is theoretically possible, but many rely on engineered molecules that are costly to manufacture and difficult to scale.
The new study focused on keratin, a structural protein found in hair, nails, feathers, horns, and wool. Keratin is rich in cysteine and has long been studied as a biomaterial because of its biocompatibility and its ability to self-assemble into organized structures. Advances in extraction techniques have made it possible to recover keratin from waste products such as wool and human hair and convert it into biomedical materials.
In the paper, titled Biomimetic Mineralization of Keratin Scaffolds for Enamel Regeneration, Sherif Elsharkawy and colleagues tested whether keratin scaffolds could promote enamel-like mineralization when exposed to saliva-derived calcium and phosphate ions. The study was conducted by researchers from fifteen institutions, including University of Toronto, Chalmers University of Technology, Imperial College London, Paul Scherrer Institute, and École Polytechnique Fédérale de Lausanne.
The researchers first extracted and purified keratin from wool. They then fabricated porous keratin scaffolds and applied them to tooth surfaces in laboratory experiments. These samples were exposed to artificial and saliva-based mineral solutions containing calcium and phosphate ions. Over time, the team analyzed how minerals nucleated and grew on the keratin matrix using microscopy, crystallographic techniques, and mechanical testing.
The experiments showed that keratin acted as an organized template for hydroxyapatite deposition. Calcium phosphate crystals formed on the scaffold and developed into a dense mineral layer that resembled enamel in both structure and composition. The coating continued to recruit minerals from the surrounding solution, indicating that the process was self-sustaining as long as ions remained available.
Mechanical measurements showed that the regenerated layer was five to six times harder than conventional dental resin used to treat early carious lesions. The material also sealed dentinal tubules, the microscopic channels that transmit thermal and chemical stimuli to the tooth pulp. Closing these channels suggests that the coating could reduce dentinal hypersensitivity in addition to restoring mineral structure.
The authors concluded that keratin can serve as a biomimetic matrix for enamel regeneration while also offering a sustainable alternative to petroleum-derived restorative materials. In a statement reported by the British Dental Journal, Dr. Elsharkawy, consultant in prosthodontics and senior lecturer at King’s College London, said: “We are entering an exciting era where biotechnology allows us not just to treat symptoms but restore biological function using the body’s own materials.”
The study does not show that human teeth can yet be regenerated in routine dental practice. All experiments were performed in vitro under controlled laboratory conditions. The regenerated enamel layer was limited in thickness, and the authors noted that additional work is needed to confirm long-term biocompatibility, durability, and performance in the complex environment of the human mouth. Factors such as chewing forces, bacterial biofilms, dietary acids, and individual differences in saliva could affect real-world effectiveness.
The paper is therefore best understood as a proof-of-concept study rather than a clinical demonstration. It establishes that keratin, an abundant waste-derived protein, can direct the formation of a mineral layer with enamel-like characteristics and favorable mechanical properties. It does not establish that a toothpaste or gel containing keratin will repair cavities in patients, nor does it show that the treatment is ready for regulatory approval.
Even so, the work adds to a growing body of research suggesting that future dental treatments may rely more on biological materials that guide the tooth to rebuild itself rather than on inert synthetic fillers. Because keratin can be sourced from inexpensive materials such as wool and hair, it may offer a practical manufacturing advantage if clinical studies confirm its safety and efficacy.
Reference:
Gamea, S., Radvar, E., Athanasiadou, D., and colleagues. Biomimetic Mineralization of Keratin Scaffolds for Enamel Regeneration. Advanced Healthcare Materials, 2025. DOI: 10.1002/adhm.202502465.
SUMMARY:
Scientists Turn Hair Protein Into Tooth Armor…And It’s Harder Than Dental Fillings
A structural protein your body already makes is redefining how dentists could rebuild teeth instead of simply patching them.
Researchers at King's College London demonstrated that keratin extracted from wool forms an enamel-like mineral coating on damaged teeth when exposed to calcium and phosphate in saliva. In laboratory experiments, the regenerated layer became five to six times harder than conventional dental resin, crossing a critical mechanical threshold for restoring tooth integrity. The material also sealed dentinal tubules, mitigating the sharp stressors that trigger sensitivity to cold, heat, and sugar. Findings reveal that a waste-derived protein can leverage the mouth’s own chemistry to foster highly organized crystal growth remarkably similar to natural enamel.
Senior author Sherif Elsharkawy said, “We are entering an exciting era where biotechnology allows us not just to treat symptoms but restore biological function using the body's own materials.” His team’s work demonstrates how regenerative dentistry is evolving from synthetic patchwork toward biologically integrated repair. By navigating the tooth’s mineral environment, keratin provides a potent scaffold that supports resilience while reducing reliance on petroleum-based plastics. Experts at King's College London argue that this holistic strategy could improve both structural durability and everyday comfort.
As we continue to engineer materials that cooperate with human biology, the boundary between repair and regeneration is rapidly dissolving. This discovery proves that abundant proteins once discarded as industrial waste can be transformed into sophisticated medical tools. In an era of biotechnology-driven innovation, the future of stronger teeth may begin with the same protein that gives hair and nails their extraordinary strength.
