Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis from periodontal pockets.

The aims of this 6-month longitudinal study were: (1) to investigate to what extent root debridement of pockets in adult periodontitis will reduce the subgingival presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and some other bacterial groups; (2) to relate the microbiological results following debridement to clinical measurements of healing. 16 patients and a total of 111 periodontally involved sites with probing depth greater than or equal to 6 mm served for the study. Duplicate subgingival microbial samples and duplicate clinical recordings were obtained 1 week apart at baseline and at 6 months following supra- and subgingival debridement. The results demonstrated reductions of the mean total viable counts and reductions of the mean counts of several of the cultured groups of micro-organisms coupled with significant improvements of mean clinical measurements. B. gingivalis was eliminated from a majority of infected subgingival sites. A. actinomycetemcomitans, on the other hand, still remained after therapy in a high proportion of sites initially infected with this microorganism. Subgingival persistence of A. actinomycetemcomitans appeared to be associated with a reduced healing response following debridement. Further studies are needed to clarify why A. actinomycetemcomitans is poorly eliminated following debridement. Also, the long-term clinical significance of the subgingival perseverance of A. actinomycetemcomitans needs to be elucidated.