Recolonization of the Subgingival Microflora After Scaling and Root Planing in Human Periodontitis

Abstract

The purpose of this study was to evaluate the recolonization patterns of the subgingival microflora of adult periodontitis patients after a single session of scaling and root planing. In each of eight patients, three clinically diseased sites were investigated microbiologically by darkfield microscopy and cultural analysis. After initial clinical and microbiological parameters were determined, each subject received a single session of scaling and root planing but no oral hygiene instructions. Clinical indices were measured and microbial parameters were reassessed 7, 21, and 60 days after treatment in a manner such that each of the test sites was sampled only once after treatment. Recolonization was evaluated by matching any single site with its own preoperative site. A significant improvement in probing depth was noted for up to 60 days after treatment, while the gingival index did not change markedly during the course of the study. The microbial composition of treated sites 7 days after scaling and root planing, as determined by both cultural and darkfield data, was similar to that of periodontally healthy sites. Differences between cultural and darkfield data became apparent at the 21 day sampling point. The darkfield data showed that the sites consisted of cocci with few spirochetes. Cultural data demonstrated that the majority of the cocci were anaerobic, namely Streptococcus intermedius, Veillonella parvula, and Peptostreptococcus micros. At 60 days, there was no significant variation in any of the parameters from pretreatment levels. The most prevalent anaerobic rods prior to and 60 days after therapy were Fusobacterium nucleatum, Bacteroides gingivalis, and B. intermedius. These results indicate that a single session of scaling and root planing is clearly insufficient to maintain a healthy subgingival microflora. The conficting findings between darkfield microscopy and cultural microbiology and between darkfield microscopy and clinical gingival inflammation suggest that darkfield microscopy is inadequate to identify a pathogenic microflora.