Humans have two sets of teeth. We learn this from the time we’re young. Our baby teeth come in first, then, around age six, our baby teeth begin to loosen and fall out making room for our adult, permanent teeth. Researchers from Keck School of Medicine of USC have discovered unique cellular and molecular mechanisms behind tooth renewal in American alligators, and hope to use this knowledge to someday re-grow teeth in humans.
The research team, led by Professor Cheng-ing Chuong, M.D., Ph.D published their study, “Specialized stem cell niche enables repetitive renewal of alligator teeth” in the Proceedings of the National Academy of Sciences, the official journal of the United States National academy of Sciences. Professor Chuong said in the study, “Humans naturally only have two sets of teeth -- baby teeth and adult teeth. Ultimately, we want to identify stem cells that can be used as a resource to stimulate tooth renewal in adult humans who have lost teeth. But, to do that, we must first understand how they renew in other animals and why they stop in people."
Human teeth, unlike other vertebrates, only replace their teeth once in their lifetime, despite the presence of a band of epithelial tissue called the dental lamina, a tissue that is fundamental in tooth development. The research team hypothesized that because alligators have well-organized teeth with similar form and structure to mammalian teeth, and are capable of lifelong tooth renewal, that perhaps alligators could serve as models for mammalian tooth replacement.
The team discovered that each alligator tooth is a complex unit of three components – a functional tooth, a replacement tooth and the dental lamina. The tooth units are structured to enable a smooth transition from the dislodgement of the functional, mature tooth to the replacement with the new tooth. Observing these three components, the team concluded that alligator dental lamina contain stem cells which form the replacement teeth.
"Stem cells divide more slowly than other cells," said co-author Randall B. Widelitz, Ph.D., associate professor of pathology at the Keck School of Medicine. "The cells in the alligator's dental lamina behaved like we would expect stem cells to behave. In the future, we hope to isolate those cells from the dental lamina to see whether we can use them to regenerate teeth in the lab."
It’s an exciting time in Science for teeth. Will we one day soon see teeth grown in a lab to be used for dental replacements? Or, better yet, will scientists discover a method to trigger tooth growth from the dental lamina still present in human gums? Furthermore, how will these advances change dentistry in the future? We’d love to hear your thoughts. Add your voice to the comments below, and tell us what you think about these exciting new scientific developments.
