STUDIES, IN THE RAT, OF SUSCEPTIBILITY TO DENTAL CARIES I. BACTERIOLOGICAL AND NUTRITIONAL FACTORS

¹ Departments of Bacteriology and Biological Chemistry, College of Physicians and Surgeons, Columbia University, New York City

Sixty young rats were studied in three groups, in which were tested, respectively, a low-calcium, vitamin D-free diet, a vitamin C-free diet, and a diet high in fermentable carbohydrate (all synthetic), in each case with and without the addition of human oral lactobacilli fed in an adhesive paste. All rat mouths were cultured at intervals for aciduric organisms.

The character of the growth obtained with the different diets is recorded. The presence of rickets in the first group was ascertained by line tests and ash determinations on the tibias.

Aciduric bacteria similar to Lactobacillus acidophilus were found to be a normal inhabitant of the rat mouth, their presence being constant and independent of the feeding of human lactobacilli.

No dental caries was produced, in spite of evidence of retention of food in molar pits, probably indicating the absence in these experiments of one or more factors in susceptibility to caries.