Why do we have baby teeth?

THAT'S THE WHY?Parents, you know the drill: first the tooth wiggles, then (with a little help from some eager fingers) it wobbles, next it swings like a catflap hinged on the gum until finally the last connection breaks and the pearly gnasher is proudly stowed under the pillow, ready for collection by the tooth fairy.

But apart from keeping young children entertained and ensuring the money-laden winged one stays in business, why do we get and then lose baby teeth?

It appears to be a size issue – infant jaws simply can’t accommodate a set of adult-sized teeth. So our deciduous or “milk” teeth start to form when we are in the womb and erupt during infancy and early childhood, aided and abetted by amylase enzymes in the saliva that when swallowed can eventually encourage nappy rash at the other end.

Those growing baby teeth play an important role in chewing food and the development of speech, but from about the age of six or seven they start to fall out and are replaced with larger, permanent teeth.

The adult versions develop from the same tooth buds as the milk teeth, so effectively our baby teeth act as a gatekeeper for our grown-up teeth.

As for the trigger to lose the deciduous teeth, it seems members of the Pax gene family could play a role, because people with mutations in these genes do not lose their first pearlies. Less work for the tooth fairy there, then.

– CLAIRE O’CONNELL