Water-based keratin films derived from wool restored dental enamel structure and improved mechanical strength in early-stage lesions in a laboratory model, according to new research. The study tested whether keratin’s natural protein structure could guide the growth of enamel-like minerals and repair damage caused by early demineralization.
Enamel, the hardest tissue in the human body, does not regenerate once damaged. White spot lesions (WSLs), an early sign of decay, occur when minerals are lost from the enamel surface, leaving it porous and weakened. Conventional treatment options focus on halting decay progression but cannot fully recreate the enamel’s original structure and function.
Keratin, a structural protein found in wool, hair, and nails, was extracted under controlled laboratory conditions and processed into thin films. The films naturally organized into a network of protein fibers rich in β-sheet structures, which provided a template for mineral attachment. When exposed to a mineralizing solution containing calcium, phosphate, and fluoride, the keratin scaffold guided the organized growth of hydroxyapatite crystals — the primary mineral in enamel.
Microscopy revealed that after mineralization, the keratin scaffolds developed enamel-like layers about 40–50 μm thick, with crystal alignment similar to that of natural enamel prisms. The scaffolds transitioned from β-sheet structures to α-helices near mineralized areas, a change associated with active mineral formation.
“Collectively, these findings establish keratin as a clinically viable, sustainable biomaterial for enamel repair, enabling functional regeneration of enamel architecture with a simple, solvent-free fabrication process,” said Sherif Elsharkawy, BDS, MSc, PhD, of the Centre for Oral, Clinical, and Translational Sciences, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, and colleagues.
Mechanical testing showed that keratin-treated lesions significantly recovered hardness and elasticity compared with untreated WSLs. In mineralization solution, the hardness of treated enamel increased markedly compared with untreated lesions, and elastic modulus values showed substantial improvement. Treatments performed in artificial saliva produced similar results. In contrast, resin infiltration, a current clinical technique for WSLs, yielded lower improvements in both hardness and elasticity.
Spectroscopic analysis confirmed that the new mineral was mainly fluorapatite, with some fluorite forming as mineralization progressed over 30 days. Carbonate ions were also incorporated into the mineral lattice, similar to natural enamel.
However, the study was performed entirely in vitro, meaning the results may not fully translate to the complex biological conditions of the mouth, such as saliva flow, bacterial activity, and dietary factors. Long-term durability of the regenerated enamel was not assessed, and cytocompatibility and safety studies are still needed before clinical application.
The findings suggest that keratin scaffolds could serve as a low-cost, abundant, and biocompatible material for minimally invasive repair of early enamel lesions. The natural protein’s ability to guide mineral organization may offer advantages over synthetic materials, potentially supporting broader applications in hard tissue regeneration.
The researchers noted that further optimization of the keratin structure, functionalization to enhance mineral binding, and in vivo studies are needed to confirm clinical feasibility.
If validated in patients, keratin-based scaffolds could expand treatment options for early enamel damage, moving beyond prevention to actual regeneration of the tissue’s natural architecture and mechanical function.
The authors reported no conflicts of interest.
Source: Advanced Healthcare Materials
