Geoff, Australia asked:
I have two young daughters aged 6 and 8. Theyíre losing their baby teeth. Iím wondering why the teeth falling out donít have any roots. Surely teeth have roots. Where are they going?
Baby teeth definitely do have roots and I have a painful personal experience to recount on this front. When I was about 14 my dentist decided that I had too many of my milk teeth left and decided they needed pulling out. He pulled them out and it was terrifically painful because they all had very long roots. The ones that had fallen out didnít have any roots.
The reason is that when you have secondary dentition, or adult teeth, they come up underneath where your baby teeth are and they erode the root away so this loosens the tooth and makes it fall out. Only once thereís a secondary tooth to come in its place because evolutionarily speaking it wouldnít do to have a period with no teeth. If all your teeth just fall out then youíd have nothing to replace them with. You might starve if you were back in ancient history and didnít have the welfare start to look after you with pot noodles. Thatís why you have this dissolving of the root in order that the tooth can be replaced by secondary dentition. What heís seeing is nature in action.
Geoff asked the Naked Scientists: I have two young daughters, aged 6 and 8, who are in the process of losing their baby teeth. I'm just wondering why the teeth that fall out have no roots, like the ones you see on teeth that are knocked out or removed. Do the adult teeth moving up from below gradually destroy the baby teeth's roots and is this why they fall out? Thanks. What do you think? Refractor, Thu, 12th Jun 2008
Very good questions.. I always wondered about that..Thanks Chris and thanks for the podcast Link! Karen W., Tue, 29th Jul 2008