Bacteriological Studies on Experimental Dental Caries in the Rat: II. Changes in Tooth Surface Flora Associated with Development and Inhibition, of Dental Caries

Abstract

general the same groups of microorganisms that are found in the normal, non-carious oral flora. These findings indicate that if the cause of caries is bacterial it lies in increased incidence or increased activity of organisms already present, in species or varieties not easily distinguished from closely related forms commonly present in the normal flora or in forms not readily isolated by the laboratory methods ordinarily used. There have been many studies2,3 showing that lactobacilli, though often found in human mouths showing no evidence of caries activity, are increased markedly in numbers in active dental caries. This is presumably true also of certain streptococci.4-6 The results of several investigators7-9 have shown that the oral micro-organisms commonly believed to be associated with human caries are also found in the oral flora of the rat. The present series of studies was undertaken to try to determine, first, whether there are any significant changes in the oral flora which can be shown to be associated with the development of dental caries and, second, if the production of caries in rats could be prevented by chemical means, whether there would be at the same time inhibition of any of the flora of the carious mouth. In the preceding paper9 the various micro-organisms in the normal oral flora were considered