Anaerobic bacteria in carious dentine

Forty-two cultures were isolated from sixteen teeth under anaerobic conditions in this investigation; of these, sixteen were isolated from the deepest level, eighteen from the middle level, five from the shallowest level, and four from the root canal. Five of these organisms were obligate anaerobes, five were gas-producing facultative, and one was a gas-producing obligate anaerobe. Twenty-nine of the cultures were coccal forms, ten were rods, and three were mixtures of rods and coccal forms which could not be separated by normal streaking techniques. The presence of facultative gas-producing organisms in root canals and the presence of facultative and obligate anaerobes in the deepest level of dental caries would suggest that further study of the anaerobic flora of the carious lesion is indicated.