As stated it is the result of poor nutrition.
Where people eat a traditional diet have perfect teeth. Even their face shapes are different.
http://4.bp.blogspot.com/_NGTgrdVoV8w/S-BiNdxg7dI/AAAAAAAAB1Q/oGqeAt7mm7c/s400/trad-guts-navajo.gif
Ever wondered why so many are getting fertility treatments these days?
