THE MICROBIC FLORA OF THE DENTAL PLAQUE IN RELATION TO THE BEGINNING OF CARIES

¹ Department of Bacteriology and Parasitology and the Walter G. Zoller Memorial Dental Clinic, University of Chicago, Chicago, Ill.

The cultivable microbic flora of dental plaques has been studied beginning with the newly erupted tooth and continuing through the period of early enamel decay until after carious lesions had become well established.

Changes in the frequency of isolation in culture of several types of bacteria have been observed. Leptotrichia and actinomyces, alpha hemolytic streptococci, fusiform bacteria and several species of Neisseria were among those forms which decreased in incidence with the progress of the lesion. Lactobacilli were the only bacteria for which there was definite evidence of increased incidence in association with the development of carious lesions.