Dental Caries in the Albino Rat in Relation to the Chemical Composition of the Teeth and of the Diet

Abstract

Albino rats were fed synthetic cariogenic diets which differed from one another only in the calcium content which was changed by the addition of CaCO₃ to produce different Ca/P ratios. The phosphorus content of the diet was maintained at a constant level of 0.5%. A progressive decrease in the cariogenicity of the diet occurred as its Ca/P ratio was increased from 1:2 to 1:1 and 1:0.5. There was no further reduction in cariogenicity when more calcium was added to give a Ca/P ratio of 1:0.3. This modification in the cariogenicity of the diet by changing the Ca/P ratio did not produce any detectable changes in the composition of the molars. The composition of the incisor teeth which were formed during the feeding period was likewise the same on diets with the widely divergent ratios of 1:2.0 and 1:0.3. From these observations considered along with others previously reported, it is concluded that changes in the cariogenicity of the diet induced by changing the Ca/P ratio in our experiments must be attributed to the actual calcium and phosphorus content of the diet and not to its Ca/P ratio.