The Role of Bacillus Acidophilus in Dental Caries**A report of the work done in the University of Michigan with the assistance of a grant from the American Dental Association.

Studies of the Cause and Nature of Dental Caries

“…The published reports of four of the outstanding studies of the last decade on the bacterial flora of carious cases were in agreement as to the importance of lactobacilli in the etiology of caries. These findings of Bunting (8,9), Rodriguez (71), McIntosh (57), and Jay (49) were also basically in accord in this respect with the results of Howe's earlier studies (43). The results obtained by these investigators agreed because they all used a strongly acid broth to prevent the growth of all except the aciduric types of microorganisms.…”

“…Historical The fact that several workers have found lactobacilli in association with caries of enamel has raised the question: What is the species of these lactobacilli? This question is chiefly bacteriologic in nature, as the common tooth strains found by Morishita (62,63), Rodriguez (71), and Bunting (8,9,10,11,12) agree in general characteristics with the tooth strain most commonly found in our studies. Whether these tooth strains should be named Lactobacillus acidophilus, odontolyticus, or acidophilus odontolyticus, the fact remains that recent investigators of this subject have been referring to organisms that are nearly if not wholly alike in morphological, biochemical, and serological characteristics.…”

“…In addition to Miller, Black (2), Williams (81,82), and Gies and his collaborators (21,22,23,24,25) have made outstanding contributions to the knowledge of local environmental influences on dental caries. More recently McIntosh (57), Rodriguez (71), and Bunting (8,9,10,11,12) have given more detailed bacteriological information of the carious process. These latter three investigators agree as to the importance of lactobacilli in producing the acid that decalcifies enamel.…”

Oral Microbiology

“…Since the discovery of Lactobacillus acidophilus by Moro in 1900 (120) Classification of the lactobacilli has been difficult. Hadley and associates (126) identified four morphological groups which have been used as the base for further study by most subsequent work ers. Howitt (128) and Howitt & Fleming (6) found seven fermen tation groups among 77 strains of oral origin.…”

Studies, in the Rat, of Susceptibility To Dental Caries I. Bacteriological and Nutritional Factors1

“…Among the many possible factors involved in this problem, four, which have been given prominence by recent investigations, are dealt with in this study: the possibilities that (a) the presence or absence of lactobacilli may determine the incidence or absence of caries (14,15,22,1,2,3); (b) the character or amount of carbohydrate in the diet may affect the incidence of caries directly (24), or determine the presence or absence of lactobacilli in the mouth (13); (c) the inception of the carious process may be encouraged by or require either a rachitic nutritional deficiency (6,7,16,17,18), or (d) a scorbutic nutritional deficiency (26,11,12,8).…”