[Rytwyng]

MANY primitive people had perfect teeth. Research in the 1930's found plenty of isolated populations - remote European and African villages, South Sea Islanders, etc -- still living on their native diets, with perfectly straight, decay free teeth.

However, upon adopting the calorie-rich but relatively nutrient poor industrialized diet, these people got all our dental problems -- decay in the first generation and, narrow dental arch, crookedness, impactions, etc. in the subsequent generations (who got substandard nutrition from conception onward.) And with the teeth, the overall bodily heatlh failed too.

The bottom line -- our dental problems are all dietary: Ancient Dietary Wisdom

[A Ruckus of Dogs]

Interesting article, considering how many kids wear braces these days. It's implying that narrow faces/jaws are abnormal.

[AZLiberty]

Tooth decay is not entirely dietary. It is caused by a particular type of bacterium, streptococcus mutans, that is commonly transmitted from mother to child. Many in the dental community believe that children of a mother with poor dental health are at much higher risk of tooth decay, because of the additional exposure to the bacterium. Vaccines are being developed against this bacterium, and mutant strains of the bacterium are being developed that lack the genes to turn sugar into damaging acid.

Hence, it's possible that these isolated populations benefited by being isolated from the tooth decay bacterium rather than from the tooth decay diet.