Caries always begins on the outer surface, never in the interior, of a tooth, which warrants the very logical conclusion that caries is caused by external factors. Caries occurs in the unhygienic mouth : one that harbors accumulations of food-debris and acid-forming microorganisms, and favors plaque formation. Physical properties of a diet directly influence the hy‑gienic state of the teeth, as well as the anatomic and physiologic developments of the masticatory apparatus. Comparison of mouths of modern man with those of ancient peoples shows that the masticatory apparatus has undergone retrogression, both anatomically and physiologically. The soft and sophisticated nature of modern food is responsible for improper development and lack of function of the masticatory organs, and for unhygienic states of the oral cavity. Radical revision of the manner of preparing food would greatly facilitate prevention of caries.
References: Den. Cosmos, 1935, 1936; J. Am. Den. Assoc.(Den. Cosmos), 1937, 1939; Am. J. Orthod., 1939.