Gwern is correct here -- paleolithic populations tended to have excellent dental health if skeletal evidence is anything to judge by, and the case of modern forager groups is often determined mainly by the degree to which they now consume high glycemic-index commodities. Chukchi and Eveny groups in Russia have appalling dental health statistics due to poor nutrition and lots of refined sugar (to the point that one Eveny nickname for sugar is "the white death" -- they have really high rates of diabetes too). Khoisan folks in South Africa, on the other hand, tend to have excellent teeth when they eat something like their traditional diet.