Abstract
The bacteriology of a spontaneous periodontal disease of hamsters was investigated. This disease is characterized by a heavy, adherent, subgingival plaque and accompanies the feeding of a high carbohydrate diet. Pure cultures of aerobic branching filaments isolated from the plaque induced the disease when inoculated orally into uninfected albino hamsters. Other plaque organisms including streptococci and various unidentified gram-negative rods did not induce the disease. A filamentous strain “labelled” by making it resistant to terramycin was used to induce the disease and to trace implantation, persistence and transfer of the organism. The “labelled” strain was recovered in high numbers from all hamsters infected with this strain and its transfer from infected mothers to offspring was observed. Simultaneous inoculations with the aerobic filament and a specific streptococcus induced both periodontal disease and caries in the same animal.