Heredity, endocrine deficiencies, marked salt-deficiencies or disturbances in ratio, and the forms in which calcium and phosphorus occur in the diet, all influence or predispose to caries, but caries is not a simple nutritional matter. It is virtually impossible, experimentally or clinically, to produce true caries— or to do more than aid somewhat in its prevention—by any known method in these relationships.
In studies of possible endocrine factors in caries, conducted at Indiana, Michigan, Pennsylvania, and Yale Universities (1926-32), endocrine variations that influenced calcium metabolism probably played minor roles in the basis of caries. Incidence of caries in individuals having marked pituitary and thyroid disturbances is higher than in so-called ” normal ” groups, but caries is not a constant result of any endocrine disturbance, and the influence is not a direct or powerful one.
In studies at Yale University (1929-32), in which a wide variety of nutritional variations was tested, marked total-salt deficiencies or very definite upsets in Ca : P ratio tended to increase incidence of caries-like lesions in experimental animals. Diets adequate in salts, but which interfered with salt metabolism or intestinal absorption of salt—such as very high-carbohydrate or very low-fat diets—tended to produce smaller carious lesions.
In studies of effects of organic calcium in the diet, as distinct from inorganic— at the Chicago Medical School and in the author’s private laboratory in Chicago, and with a series of clinical subjects (1932-33)—a low Ca: P intake in general predisposed to caries, but even at very low levels frequently did not cause true caries.
Studies of the genetics of dental disturbances, completed at Indiana and Michigan Universities (1926-28), showed a tendency to constant and recurrent caries in some families, also relative freedom from caries in others.
References: Ann. Int. Med., 1927; J. Den. Res., 1928, 1930, 1932; Am. Surg., 1937.