Effect of splint placement on black-pigmented Bacteroides and spirochetes in the dental plaque of beagle dogs.

The gingival microbiota in beagle dogs was investigated during a period of 42 days after the placement of continuous wire and arch bar splints. The splints were found to induce an increase in helicoidal-shaped micro-organisms and black-pigmented Bacteroides. Two different asaccharolytic Bacteroides types were isolated and tentatively identified as B. gingivalis and B. asaccharolyticus. In addition, B. intermedius-like organisms were isolated. The last two species were observed only after splint placement. The local accumulation of helicoidal-shaped micro-organisms in the epithelial tissue rather than in the micro-ulcerations was regarded as an indication of an active role for these spirochetes in the disease process. The observed shift toward tissue-invading and potentially pathogenic micro-organisms after splinting stresses the need for antimicrobial measures during splint placement in order to minimize periodontal destruction.