The role of salivary lactobacilli in predicting the development of dental caries has aroused much interest. A positive correlation between lactobacillus count and caries activity has been reported by a number of authors.'-10 However, some investigators found no correlation."-'4 Studies have also been made on the relationship of the fluoride content of drinking water and saliva to the salivary lactobacillus count and to the dental caries rate. Dean, Jay, Arnold, and Elvove'5 found the salivary lactobacillus counts and the caries prevalence rate to be lower in areas with a greater fluoride content in the drinking water. Clapper 1 considered this relationship valid for predicting dental caries activity. Martin and Hill,'6 on the other hand, after examining the fluoride content of pooled saliva samples from children drinking artificially fluoridated water for a period of 2 years, could not establish any relationship to their lactobacillus counts and the caries prevalence. Lerman, Gedalia, Rosenzweig, and Brzezinski17 analyzed fluoride values in the saliva of pregnant women drinking naturally fluoridated water containing 0.55 ppm F. They found no correlation between the fluoride values in saliva and their dental caries rate.The present study deals with the correlation between the fluoride level of the saliva, the lactobacillus count, and the dental caries activity in a group of 34 children, aged twelve to fourteen years, who were individually analyzed.
MATERIALS AND METHODSCollection of samples.-15-20-ml. saliva samples were obtained following the chewing of wax for approximately 10 minutes at 7:00 a.m., before morning oral hygiene or breakfast. All the children drank water containing 0.5-0.6 ppm F. No prior examination was made for the presence or degree of dental caries. The samples were collected in sterile containers. The DMFS count was made by the same investigator, with the aid of an adequate light, a dental mirror, and an explorer. It is possible that in some cases the presence of interproximal caries was overlooked, since bite-wing X-rays were not performed. However, the incidence of interproximal caries in Israeli children of this age group is infrequent,' and therefore any error due to omission of this examination was considered to be unimportant. The dental examinations were repeated 9
