Studies on Salivary Lactobacilli and Dental Caries in Children During a Dentifrice Test Program

Abstract

TlIHE primary purpose of this study was to test the effect of a dentifrice containing a dichlorophenyl methane compound on dental caries increment in a group of children. Several members of a series of halogenated diphenols had been shown to be highly bacteriostatic against mouth organisms at very low concentrations. Usage tests with a number of dentifrice formulations indicated that bis-(2-hydroxy-4, 5-dichlorophenyl) methane, which demonstrated considerable antibacterial activity, could be used at a level of 0.2 per cent without causing any irritation of the oral tissues. Other compounds thus tested were eliminated on the basis of irritativeness. The second purpose was to study salivary lactobacilli in the children, and the effect of the dentifrice on these organisms.The question of the association of oral lactobacilli with dental caries has been the subject of considerable study and some controversy. Bunting and Palmerleel found that the presence of oral lactobacilli could be correlated with dental caries activity. Later reports confirmed this observation, all considering lactobacilli, qualitatively.2-6 In much of this early work, assay was made of tooth scrapings rather than of saliva.Hadley8 developed a generally satisfactory method for quantitative estimation of numbers of lactobacilli in saliva. She reported that zero counts of lactobacilli were obtained in the majority of saliva samples from caries-free persons, while counts of over 20,000 lactobacilli per cubic centimeter were obtained from the majority of saliva samples from caries-susceptible persons. Other investigators,8-10 using the Hadley technic, attempted to extend the salivary lactobacilli-caries relationship into quantitative aspects, but without critical evaluation of the significance of different levels of lactobacilli counts per cubic centimeter of saliva.Snyder", 12 evaluated the relation of salivary lactobacilli to caries in a more strictly quantitative manner. He confirmed the association, but stated that prediction of future dental caries on the basis of existent salivary lactobacilli counts was possible only with groups, not with single individuals. Due to sporadic occurrence of lactobacilli, he proposed that evaluation of the caries activity of an individual should be based on several spaced saliva examination.12 Jay"3 stated, "Counts under 2,000 are, as a rule, unimportant. Counts from 2,000 to 10,000 are usually indicative of moderate caries activity, while counts over 10,000 generally require strict dietary treatment."