Dental Caries in the Albino Rat in Relation to the Chemical Composition of the Teeth and of the Diet II. Variations in the Ca/P Ratio of the Diet Induced by Changing the Phosphorus Content

Abstract

Quadruplicate groups of litter mate albino rats were fed from weaning on cariogenic diets in which 4 different Ca/P ratios were tested; the ratio was changed by maintaining the calcium concentration at a constant level and varying the phosphorus. In one experiment in which the animals were desalivated, there was a progressive decrease in the caries score as the Ca/P ratio was decreased from 1: 0.5 to 1: 2. Further decrease in the ratio to 1: 3 had no effect on the incidence or extent of caries. In a second experiment in which the animals were not desalivated in order to avoid the complications of caries over the same feeding period, the nitrogen, calcium, phosphorus, magnesium, fluoride and CO₂ content of the teeth was the same on each of the 4 diets. The effect of varying the Ca/P ratios of the diet on its cariogenicity was, therefore, not related to changes in the composition of the teeth.