The solution to having a healthy smile could come from a place where no dentist would ever want to get their hands: the mouth of the alligators.

To keep their grin unchanged and bite the prey without difficulty, these reptiles have developed a mechanism of dental regrowth that allows each specimen to change 80 teeth even 50 times over the course of a lifetime. A good fortune that we men are denied: the only way to replace a missing tooth, for us, is to put a fake one on it.

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There are parts of our body in contact with the external environment that regenerate continuously: hair and nails grow back, and the cells of the epidermis are promptly replaced. In the same way, some reptiles like crocodiles and alligators can make their newly fallen teeth grow back.

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A group of researchers from the National Taiwan University studied tissues of embryos and young specimens of American alligator (Alligator mississippiensis) discovering that each tooth of this animal develops into blocks of three elements: the actual tooth, which grows externally; the dental lamina (the tissue that will give rise to the "reserve" tooth) and stem cells that will turn into new tissue when the replacement tooth is also dropped. When the outermost tooth falls, the spare one begins to fall and special molecular signals stimulate the stem cells to differentiate into cells of new dental tissue to create a new replacement tooth.

Now the researchers are trying to decipher these molecular signals to understand if one day - but this remains a remote hypothesis - we will be able to regenerate the fallen teeth like hair (our incisors are not so different, except for the size of those alligators); and above all, if at the base of some diseases that involve the growth of supernumerary teeth there are wrong molecular signals that it is possible to inhibit.

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