Jaws – The Story of a Hidden Epidemic

Most of the books I feature in my blog are free eBooks available from Internet Archive (or similar sources). This is a more recent book that I purchased in Kindle form:

Jaws: The Story of a Hidden Epidemic by Sandra Kahn and Paul R. Ehrlich published in 2018 by Stanford University Press. It’s available from Amazon for about $10.

The basic idea is that the way we grow up and live now causes our jaws to be malformed compared to the jaws of our ancestors.

It has been observed that ancient human jaws had room for wisdom teeth….and the lower jaw continued to fit with the upper over the lifetime. That rarely happens now and there is a lot of orthodontic intervention to correct problems that develop.

So – the book sets out to identify what is different now…why is there so much malocclusion in childhood and beyond….and obstructive sleep apnea as we get older?

One of the ideas from the book was that breastfeeding and then providing chewing opportunities for babies (rather than relying exclusively on pureed foods) as soon as they begin to get teeth helps the jaw form properly. In my family, that happened well enough that my sisters and I didn’t need braces (although we did need to have our wisdom teeth removed). I was old enough to remember when my youngest sister had just been weaned and was teething; my mother had given her a piece of celery to chew on; my mother took the celery and gently felt to see if the tooth had emerged and my sister bit down so hard that the finger bled a little (I always though my sister had assumed that the finger was the celery and she was finally going to get the bite!). The next generation was not so lucky – all 5 of my mother’s grandchildren required braces. I hope pediatricians are prompting new parents to give toddlers opportunities to chew after being weaned. And - it turns out that breast feeding requires more jaw power than bottle feeding so why don’t we have modified bottles that can do the same for situations where a baby is not breast feeding!

Another idea is that not only do we need to learn good posture for our back; jaw posture is important too! Correct jaw posture is the mouth closed with the teeth slightly touching….not with the jaw lowered. The airway is at its maximum when the jaw is closed! The muscles developed to close the jaw are important to maintaining that open airway. In some cultures, mother’s gently close the baby’s mouth after they finish nursing to encourage them to breathe through their nose and develop good jaw posture. I’ve been consciously monitoring my jaw poster and building up the appropriate muscles…I do find that my sinuses empty more easily, and breathing is very relaxed…although it felt strange at first. I rarely breath through my mouth but I was holding my jaw slightly open as my ‘default’ rather than the closed jaw that is good posture. Notice that it is also easier to swallow pills with the jaw closed!

There was an article published in Bioscience by the authors in September that is available online that provides some highlights from the book and pictures that illustrate the difference proper jaw posture makes.