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General Science => General Science => Topic started by: Refractor on 12/06/2008 08:05:42

Title: Why do baby teeth have no roots when they fall out?
Post by: Refractor on 12/06/2008 08:05:42
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?
Title: Why do baby teeth have no roots when they fall out?
Post by: chris on 12/06/2008 18:18:25
Hi Geoff

Welcome to the forum!

This is an excellent question. The reason why baby or "deciduous" teeth appear to be rootless is because the root resorbs (is dissolved) as the secondary tooth grows up beneath it. This has the effect of loosening the tooth so that it falls out more easily, but only when there will soon be a permanent secondary tooth to replace it.

In this way a child is never left toothless, which in the "wild" might have had consequences for an individual's ability to feed themselves.

I can also confirm from painful personal experience that deciduous (milk) teeth definitely do have roots, because I still had quite a few primary teeth (chiefly molars) even when I was 14, and my dentist insisted on pulling a load of them out. The lack of any adult teeth ready to take their place meant that the extraction was painful, but not half as painful as having to eat with nothing but my incisors for 6 months!

Chris
Title: Why do baby teeth have no roots when they fall out?
Post by: thedoc on 26/07/2008 18:26:50
Listen to this question on our podcast by clicking here (http://www.thenakedscientists.com/HTML/podcasts/show/2008.06.22/)
Title: Why do baby teeth have no roots when they fall out?
Post by: Karen W. on 29/07/2008 02:11:46
Very good questions.. I always wondered about that..Thanks Chris and thanks for the podcast Link!

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