Microbial succession in recolonizing deep periodontal pockets after a single course of supra- and subgingival debridement

In the present study, the effect of supra and subgingival plaque debridement on the dynamics of the subgingival microflora in deep pockets was investigated. 8 adult periodontitis patients participated in the study. In each patient, 4 clinically diseased sites were investigated microbiologically by phase contrast microscopy for the determination of both the %s as well as the total numbers of spirochetes and motile rods and by anaerobic cultivation for the determination of the different black-pigmented Bacteroides species. After base-line examination, patients were treated by mechanical removal of supra- and subgingival plaque deposits. 2 and 8 weeks after treatment, clinical and microbiological parameters were re-evaluated. During the experimental period, no oral hygiene procedures were performed in order to achieve fast recolonization of the pockets. Treatment resulted in a significant reduction in probing pocket depth and gain of probing attachment. 2 weeks after treatment, no further improvements could be observed. A positive correlation was found between the reduction in probing pocket depth and decrease in Bacteroides gingivalis (P less than 0.009) and between gain in probing attachment and reduction in the % of B. gingivalis (P less than 0.009). No correlation between these clinical parameters and B. intermedius, spirochetes or motile rods was apparent. An inverse relationship between B. gingivalis and B. intermedius was observed. We found that changes in %s of spirochetes and motile rods are not correlated with changes in total numbers of these bacterial groups. It was concluded that monitoring of %s of micro-organisms may not supply rational information on the microbiological conditions of the subgingival area.