First person on the Lost Boys of Sudan:

400 refuge children from wartorn Sudan, despite never brushing their teeth, have little decay because of their healthy native diets

"Now it is not a simple matter of telling them to floss more or use a softer brush. He sheepishly told me, 'most of them have never seen a tooth brush'. He is not being figurative, it is the truth. The good side, their native diet in Africa had very little refined sugar, so decay is not a big issue."