The Influence of Local Periodontal Environmental Factors on Subgingival Plaque Reformation after Scaling and Root Planing

The purpose of this study was to investigate the influence of local periodontal environmental factors associated with periodontitis on subgingival plaque reformation after scaling and root planing. A healthy site and a periodontitis site were selected from each of 10 periodontitis patients for this experiment. In both sites, scaling and root planing were performed with an ultrasonic scaler and, if required, by hand curettes, at baseline. In each pocket or sulcus site a dentin strip was inserted and fixed with Super-bond ® . After two weeks, the dentin strips were removed and examined by scanning electron microscopy. The following results were obtained: The average length of accumulated subgingival plaque was 2.5±0.9mm in all periodontitis sites and 0.6±0.6 mm in all healthy sites, showing a significant difference. The average length percentage of accumulated subgingival plaque by probing depth was 26.7±23.0% in healthy sites and 50.0±29.1% in periodontal sites among 6 paired cases. This difference was also significant. The microflora of the subgingival plaque were mainly cocci and short rods, but spirochetes were occasionally observed at healthy sites. On the other hand, the microflora in periodontitis sites showed cocci, different sized rods, filaments and spirochetes. Leukocytes were also observed in high numbers. The above results suggest that subgingival plaque reformation and the associated microflora may be markedly influenced by the local periodontal environment.