Researchers at Zhejiang University in China have developed a biomimetic regenerative solution that could be applied to a cavity to establish crystalline-amorphous mineralization that induces the growth of enamel with precise maintenance of the original structural complexity within 48 hours.
“To the best of my knowledge, this has been the best tooth enamel regenerative substance so far, and it has the potential to repair tooth enamel clinically in a real sense,” said Helmut Cölfen, a professor of physical chemistry at the University of Konstanz.
“Enamel resembles a layer of natural inorganic crystalline mineral and is primarily composed of nonstoichiometric fluoridated carbonite apatite crystals that are tightly packed with well-defined orientations to ensure striking hardness,” said Dr. Shao Changyu, lead author of the study.
As a highly mineralized biological tissue, enamel is seen as a purely inorganic substance and cannot self-repair do to a lack of a bioorganic matrix. Even though it is the hardest tissue in the body, enamel is susceptible to degradation, especially by acids from food and drink. Once it is damaged, teeth develop cavities.
Enamel remineralization is the most formidable challenge in bionics, the researchers report. Previous endeavors to regrow enamel by using a range of materials including composite resins, ceramics, and amalgam have failed to achieve permanent repair because of the imperfect compatibility between these foreign materials and the native enamel.
“Optimally, scientists should achieve the unity of material, structure, and mechanics and repair enamel in situ,” said Dr. Liu Zhaoming, coauthor of the study.
The researchers found that mixing calcium and phosphate ions, two minerals found in enamel, with trimethylamine in an alcohol solution causes enamel to grow with the same structure as teeth. When the mixture was applied to human teeth, it repaired the enamel layer to around 2.5 µm of thickness. It also achieved natural enamel’s structure within 48 hours.
“The materials we used in experiments were identical to the human tissue, thereby achieving complete structural regrowth,” said Zhaoming.
The discovery has not yet been proven to work in the hostile environment of the mouth, but the researchers say regrown enamel may be tested in people in the near future. One of the researchers who has a crack in one of his teeth says that he is willing to be a subject for such as trial, since his dentist has told him that nothing else could be done to repair the tooth.
“Although we have achieved a precise duplication of the hierarchical and complicated structure in natural enamel, there is a wide spectrum of dental cavities. We need to develop our regenerative model for different circumstances so as to ensure controllability and effectiveness,” said Changyu.
The researchers say this biomimetic tactic for enamel regeneration can be extended as a general strategy for constructing structurally complex materials by establishing a biomimetic mineralization frontier for continuous and epitaxial construction in which the ion clusters act as basic building blocks. This achievement will deepen the understanding of biomineralization, the researchers add, as well as provide a new pathway for bioinspired design and production.
The study, “Repair of Tooth Enamel by a Biomimetic Mineralization Frontier Ensuring Epitaxial Growth,” was published by Science Advances.