Im reading the book "Nutrition and Physical Degeneration"
by Dr Weston Price DDS...read the whole thing here:

http://gutenberg.net.au/ebooks02/0200251h.html

Here are two pics, both of Swiss children.

Above..Children from isolated mountain villages.
Their staple was rye bread with liberal amounts
of highly mineralized grass-fed butter.
They did not use toothbrushes.

Above...Children from towns where refined foods were adopted.
They used white flour and jam extensively.
They used (or at least were introduced to) toothbrushes.
The crowding in the bottom two pictures is not hereditary.

Im being blown away by this book...check it out for sure.