THE OCCURRENCE OF LACTOBACILLI AND OTHER ACIDOGENIC ORGANISMS IN THE SALIVAS OF SELECTED CARIES-FREE CHILDREN

¹ Hygienic Laboratory, University of Michigan, Ann Arbor, Michigan

The occurrence of lactobacilli in the salivas of selected caries-free children was observed over an 18 month period. In the salivas of 17 children from an institution in Maumee, Ohio, only 11 of 159 specimens were positive for lactobacilli, whereas of 178 specimens of saliva from 21 Ann Arbor public school children 85 were positive for lactobacilli. Similarly, the teeth at the end of the study showed only 1 Maumee subject to have a small extension, the significance of which was questioned, while 6 Ann Arbor children were definitely subject to caries. Although as individuals there were several apparent exceptions, as the one Maumee and several Ann Arbor subjects who had lactobacilli more or less consistently present in their salivas but had no caries, it must be remembered that these children were carefully selected as caries-free in the beginning and did not represent a cross-section study. It is obvious that further individual studies should be made. Nevertheless, as groups divided on the basis of lactobacillus population, those children who had no lactobacilli in their salivas at the time of collection remained free from caries, and those who had significantly appreciable numbers of lactobacilli in the saliva showed varying amounts of decay. Other aciduric organisms were isolated, but of the yeasts, streptococci, and staphylococci only the yeasts seemed to have any relation to the caries observed and this role was apparently secondary to that played by the lactobacilli.