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Did you know that the most valuable tooth in history was one of physicist Sir Isaac Newton’s? It was set in a ring and sold in 1816 for the equivalent of nearly $36,000 in today’s money.
But most of us consider our teeth to be most valuable when firmly in our jaws, to be displayed in a dazzling smile. But despite rates of tooth decay decreasing since the introduction of fluoride toothpaste and better oral hygiene, a quarter of people over 60 have lost all of their teeth.
This is bad news for us, as unlike animals such as the alligator, we cannot replace our adult teeth with real teeth – once they’re gone, they’re really gone, and can only be replaced with artificial ones. (There was a nasty period in history when they tried transplanting dead people’s teeth into the mouths of the rich and famous, but fortunately that trend died – along with the teeth).
Tooth remnants are the key
Scientists have found that alligators can replace lost teeth because in their jaws they have remnants of dental lamina. This is the primitive forerunner of animal (including human) teeth, which is present from week six in a human fetus, and later becomes tooth enamel.
How does it grow into teeth?
When an alligator loses a tooth a cascade of events is triggered which stimulate the development of the dormant dental lamina into a new tooth. Scientists speculate that this involves signalling between molecules by means of special chemical messengers and the development of stem cells which are basic forerunners of all cells and have the potential to develop into any type of cell.
How could this be translated into humans?
Scientists have closely studied young alligators to try and discover the precise mechanism by which the remnants of dental lamina develop into new teeth. As a result they have been able to grow tooth cells in the laboratory.
Unlike alligators this mechanism is not naturally present in humans, but remnants of the raw material – the dental lamina - do persist in our jaws. Once scientists have discovered precisely what triggers them to develop into new teeth, it is possible that they can use it to help humans grow replacement teeth.
What other applications are there for this research?
In Cleidocranial dysplasia and Gardner’s syndrome, people develop extra ('supernumary'), unwanted teeth. In other people the remnants of dental lamina are abnormally stimulated to grow, forming tumors in the jaws.
One of the researchers explained how understanding the mechanisms triggering tooth development might benefit different groups of people: