[Microbiological findings of subgingival plaque during long-term experimental gingivitis in humans].

During six month of abolished oral hygiene and concomitant development of gingivitis, the buccal subgingival microbiota was studied by darkfield microscopy as well as by cultural methods. Five dental students gave written informed consent and participated in this trial. In darkfield microscopy there was a slow reduction in the proportion of coccoid forms concomitant with an increase in the proportion of rods, while spirochetes were rarely detected during the entire experimental period. However, the cultural data revealed a decrease of the Gram-positive facultative and an increase of the Gram-negative anaerobic microorganisms after 6 months of abolished oral hygiene. The bacteriological data show, that in buccal sites--even after 6 months of abolished oral hygiene--the subgingival microflora reflects a population typical only for an initial lesion.