Diets consisting of unrefined foods, whether of dairy or non-dairy types— when adequate in mineral content according to present biochemical standards, and accompanied by active outdoor-living in abundant sunshine—favor resistance to caries. When ” biochemical ” immunity against caries exists in high degree, other commonly emphasized factors, such as hygienic measures, anatomical form, etc., are of minor significance. When this systemic resistance is low or inadequate, oral cleanliness is very important, and anatomical form, mal-alignment, stagnation areas, hereditary tendencies, age, etc., are significant factors in susceptibility or immunity to caries.
Rats. Caries can be produced and prevented at will in rats by dietary means. Adequate supply of phosphorus is an important factor in its prevention ; adequate supply of vitamin D may prevent or delay its onset. The role of vitamin D is not as important as that of phosphorus.
Man. Addition of vitamin D to diets previously considered adequate in all respects, including phosphorus intake, is an important factor in prevention of caries. Administration of vitamin D (irradiated ergosterol) to children living under good hygienic and dietetic conditions markedly decreased caries.
Chinese. Incidence of caries among Chinese is considerably lower than among Western peoples. In West China it approximates 45 percent 3 in adults, 70 percent in children. Incidence of caries in children is apparently increasing in urban centres, where it is higher than in country areas. This increase may be related to nutritional dysbalance caused by definite increase in the amount of sweets consumed by children, often at the expense of other foods.
Tribal groups. Among tribal groups of the Szechwan-Tibetan borderland where corn meal, ground from whole grain, is the staple diet and outdoor life is universal—for example, among Chiang, Chia-Rong and Hsi-Fan tribespeople‑
1 The names of the secondary authors of summaries are listed on pages 18 and 19.
2 The dates of the summaries in this volume are those of original presentation or subsequent revision.
3 In this summary the percentage data refer to proportions of persons having caries in any degree.
26 SUMMARIES ON CARIES
incidence of caries is approximately 37 percent. In groups such as Chuan Miao, where polished rice and corn are used as staple food and where general malnutrition is more evident than in the groups just mentioned, caries incidence is approximately 52 percent. Among Tibetans (various ethnic groups in Hsi K’ang or Eastern Tibet), where dsamba (barley flour, butter and tea) plus cheese and other dairy products are widely used, and where the natives live outdoors at high altitudes, incidence of caries is approximately 42 percent. In all of these ethnic groups, hygienic conditions are extremely unfavorable. Cavities are located predominantly in pits and fissures of molars. Sugar is not consumed as a separate article of diet.
References: J. West China Border Res. Soc., 1929; J. Den. Res. (Proc. Int. Assoc. Den. Res.), 1931, 1932; J. Am. Den. Assoc., 1933, 1934; Int. J. Orth. Oral Surg., 1933.