Root Regeneration May Depend on Proteins



Dentists someday may be able to replace missing dentition with a completely regenerated tooth structure instead of an implant, according to research from the Herman Ostrow School of Dentistry at the University of Southern California.

As an anchoring anatomical structure, the tooth’s root is crucial for the physiological function of teeth and for the tooth’s own health. Yet root development, which occurs after the initiation of crown development, has not been extensively studied.

“We’re one of the very few labs who have really taken this tooth development study into the later stages of development and to begin to understand what controls root formation,” said Yang Chai, DDS, author of the study and associate dean of research at the school.

The researchers removed certain proteins such as Shh and Nfic involved in root development to determine how and when they are necessary. Later, they mutated specific genes at specific developmental stages to determine which genes were required at which times for root development. This provided further insight into the molecular mechanisms regulating tooth root development.

“This is a major step in a long journey in which we’re trying to understand how to build a biological root in order to be able to use that for restoration of missing dentition,” Chai said.

This discovery could change how dental implants are treated in the distant future. Implants currently require dentists to fuse a post into a patient’s jawbone and cap it with a natural-looking crown. This approach has its limitations, said Chai.

“All of our natural teeth are suspended within the socket with periodontal ligament,” he said. “So when you bite on a piece of almond versus a piece of soft bread, you use different forces because your teeth can actually sense how much force you need to exert based on how hard the substance is.”

A biological root would allow for this type of neurointegration, which is absent in today’s approach using a post fused into bone.

“Regenerating a root can be done and then coupled with a porcelain crown and post, so we can really restore function and aesthetics at the same time,” Chai said.

Chai wrote the study, “An Nfic-Hedgehog Signaling Cascade Regulates Tooth Root Development,” with Peking University postdoctoral research associate Jingyuan Li and research assistant professor Hu Zhao. It was published in Development.

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