American alligators have a smile that only a mother could love, but new research finds that these huge meat-loving reptiles could help to revolutionize tooth replacement in humans.
The statistics about alligator teeth are remarkable. Most individuals go through around 3,000 teeth in a lifetime. It's estimated that a 13-foot-long alligator replaces each of its 80 teeth about 50 times throughout the animal's existence.
Now the light bulb moment for scientists is that alligator teeth are not all that dissimilar from human ones. The main difference is that when an adult human loses a tooth, it's gone forever.
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(That offers an interesting clue as to what kind of diet our early human ancestors had. It couldn't have been too hard or tough, or else we would have evolved a better tooth replacement system.)
For this latest study, published in the Proceedings of the National Academy of Sciences, Cheng-Ming Chuong of National Taiwan University and colleagues studied repetitive tooth formation in American alligators. Detailed imaging of gator teeth determined that at the early tooth development stage, the alligator's dentine bone-like material forms a bulge at its tip. The tip houses what are believed to be dormant stem cells.
When the gator loses a tooth, certain types of proteins are released that activate these stem cells. The proteins quickly go into action, initiating growth of a new tooth. This happened even when researchers pulled out alligator teeth.
By identifying the individual types of "activator" proteins and the stem cells, the scientists can likely apply the tooth renewal process to humans with missing teeth.
As Chuong and colleagues wrote, "Based on our study, it may be possible to identify the regulatory network for tooth cycling. This knowledge will enable us to either arouse latent stem cells in the human dental lamina remnant to restart a normal renewal process in adults who have lost teeth or stop uncontrolled tooth generation in patients with supernumerary teeth."
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Clinical trials on humans are underway, after researchers successfully caused teeth to regrow in mice and monkeys.
As for stopping uncontrolled tooth generation, this refers to a condition known as hyperdontia - which basically means that the person has more teeth than they should. This might seem like a problem we'd all want to have, but people with the condition can suffer from dental problems, jaw pain, headaches and other troubles tied to the extra teeth.
Hopefully future dentists will be able to fully control tooth growth, either initiating or stopping it at their will. Dentures could then be the carbon paper of the future - rare and obsolete.
Image: Wikiimedia Commons