Key to dental enamel formation found

Scientists at Harvard-affiliated Forsyth Institute have found and replicated a key aspect of the mechanism by which dental enamel is formed.

The findings, published in the Feb. 14 Journal of Structural Biology, may lead, one day, to new, biological methods for repairing teeth and other mineralized tissues as well as to new, very hard ceramic materials.

Lead author Elia Beniash, staff scientist at Forsyth, explains that enamel, the hardest tissue in the human body, is composed mainly of calcium phosphate mineral crystals. “It is well known that enamel’s strength and durability derive from the unique way in which those crystals are organized into parallel bundles called ‘rods.’

“In the current research, carried out in test tubes, we demonstrated that the protein amelogenin plays a key role in regulating the organization and growth of these crystals and how it works. We also determined that newly forming enamel structure emerges as a result of cooperative interactions between forming crystals and assembling proteins, rather than sequentially, as in the formation of other mineralized tissues such as bone and dentin [the bony material found under enamel, in teeth].” The scientists worked with mouse amelogenin, which is very similar to the form of the protein found in human teeth.

Henry Margolis, chair of the Forsyth Department of Biomineralization and a co-author of the article, said, “The current findings are a crucial step toward understanding the process of enamel formation. We hope this work will one day lead to an ability to repair damaged tooth enamel.”

Another long-term goal is the development of biomimetic, nanostructured materials with properties similar to those of dental enamel. Biomimetic materials or devices are those whose design, organization, and functional properties are modeled on biological systems. Nanostructured materials are those in which the organization is regulated at the submicron level during fabrication. “Such advances will rely on future collaborative studies involving chemists, biophysicists, biologists, and materials scientists,” Margolis said.

In addition to his Forsyth appointment, Margolis is associate professor in the Department of Oral and Developmental Biology at the Harvard School of Dental Medicine. The team also included James P. Simmer, associate professor of biologic and materials sciences in the Division of Prosthodontics at the University of Michigan. The research was funded by a grant from the National Institute of Dental and Craniofacial Research and through support provided by The Forsyth Institute.