In an experimental study in rats—in which ” cusp caries ” produced by coarse corn-meal was used as an index—it was found, after feeding caries- preventive diets to mothers during pregnancy and lactation, that haliver oil, in excess of the amount necessary to prevent rickets, increased caries-immunity in the young. A wide range in ratio of calcium to phosphorus was tolerated by mothers without effect on caries-resistance in the young, but an extremely low ratio reduced resistance. A 100-percent-meat diet, supplemented with calcium carbonate, reduced the number of cavities from 10 per control to 2.5 in the young of mothers on the meat diet. An optimal amount of fluorine may be necessary for development of caries-resistant teeth. In experiments with diets that initiate caries, fermentable carbohydrates and thermal shock had no effect. In experiments with diets that alter the rate of progress of caries, fermentable carbohydrates promoted enlargement of existing cavities; factors operating through metabolic channels—vitamins A and D, and increased calcium and phosphorus—had no effect.
Addendum (Aug. 19, 1939): The production of mottled enamel in rat molars provides a means to study the relation of mottled enamel and caries in a single species. Fluorine present during the period of formation of rat enamel increases caries resistance.
References: Den. Rays, 13, 8, 1937; (to Addendum) Science, 90, 83, 1939; J. Den. Res. (in press).