Lactobacillus Acidophilus and Dental Caries

The etiology of dental caries is a problem which has for many years absorbed the attention of a number of research workers. Several theories have been formulated in an attempt to establish the actual causative factor. The theory which best seems to offer an explanation is that microorganisms are present on the tooth surfaces which are capable of forming metabolic products from the foodstuffs there and that these products bring about the dissolution of the enamel .. This theory was first advanced by Miller (1890). The question then arose as to which microorganism in the mouth was capable of thi~ actionw Kliger (1915) observed a high percentage of ~· acidophilus in carious mouths and, since that time, several other workers , including Bunting and Parmelee (1925) have advanced evidence that this organism is the actual exciting cause of dental caries. The lactobacilli are highly pleomorphic i n nature and are sufficiently acidogenic and, possibly more important, aciduric to cause dissolution of the enamel. No other organism in the mouth has been shown to hav-e these essential qualities. In support of this evidence, Bunting et al. (1925) , Jay (1929), Hadley (1933), and Becks et al. have shown that a positive correlation exists between the nQmber of lactobacilli in the mouth and the incidence of dental caries. These lactobacilli do not exert their action independently of the other components of the oral cavity. It is possible that the saliva has some effect on their action, but this has yet to be proven. The bacterial plaque , on the other hand, has been established as necessary for the carious process. The organisms which compose the plaque form a filamentous meshlike structure which localizes the bacteria and the acids which they form. x.