[ItendToDisagree]

He is talking about tooth alignment (braces) not decay as in cavities. Incorrect tooth alignment can have many health risks regardless of it being a class/beauty standard.

The bacteria/decay thing is a whole other mostly preventable thing.

[Axsuul]

Early childhood diet has a huge impact on the development of the jaw. An underdeveloped jaw is what leads to crooked teeth. One substantial evidence of this are the studies conduced by Dr. Weston Price. For over ten years, he traveled to isolated parts of the globe to study the health of populations untouched by western civilization. His goal was to discover the factors responsible for good dental health. His studies revealed that dental caries and deformed dental arches resulting in crowded, crooked teeth are the result of nutritional deficiencies, not inherited genetic defects. Wherever he went, Dr. Price found that beautiful straight teeth, freedom from decay, good physiques, resistance to disease and fine characters were typical of native groups on their traditional diets, rich in essential nutrients.

https://robbwolf.com/2013/08/29/dentistry-harmony-nature/