The predominant cultivable dental plaque flora of beagle dogs with gingivitis

The predominant dental plaque flora of 15 female beagle dogs (1,3 and 6 year old) with naturally developed gingivitis was studied using a continuous anaerobic culturing technique. Supra- and subgingival plaque samples from the buccal aspect of the upper third premolar were cultured on various growth media and the organisms were partially characterized. The flora in all dogs was composed mostly of anaerobic Gram negative organisms. B. asaccharolyticus (B. melaninogenicus ss. asaccharolyticus) was found in both types of plaques in all animals and decomposed hydrogen peroxide suggesting catalase activity. F. nucleatum was found in higher proportions in the subgingival plaque as compared to B. asaccharolyticus and actinomycetes. Spirochetes were found in 10 of 15 supra- and in 1 of 15 subgingival specimens. S. mutans, S. mitior, S. salivarius, Veillonella, Selenomonas or vibrios could not be detected in any of the plaque samples. A combined data analysis showed, that the total viable CFU and the proportions of Gram positive organisms were significantly higher in the supra- than the subgingival plaque. Although the proportions of Gram negative bacteria were higher in subgingival plaque, the differences between the two types of plaques excluding F. nucleatum were not significant.