The antimicrobial and clinical effects of a single subgingival irrigation of chlorhexidine in advanced periodontal lesions.

The antimicrobial effects of subgingival chlorhexidine (CH) irrigations on the pathogenic flora in advanced periodontal lesions were assessed. Changes in the patterns of colonization within the subgingival sites were monitored by differential dark-field microscopy, in 16 patients, over a period of 10 weeks. In addition, changes in the clinical parameters of the diseased sites were also monitored. Initial base-line evaluations were made for both the clinical and microbiological parameters. 4 sites of moderate to advanced periodontal disease were selected in each patient. These were randomly irrigated with a single dose of either 0.2% CH gel, 0.2% CH solution, or physiological saline, while 1 site was left as a control. The patients were seen weekly, until the 5th week, then at the 7th and 10th weeks. At each appointment, a microbiological sample was taken from the subgingival region of each site, together with an assessment of the clinical indices. Results indicated that a single irrigation of an 0.2% solution of CH or 0.2% CH gel had a marked effect in decreasing the % of spirochaetes and, to some extent, motile bacteria. There was a concomitant shift in colonization to cocci, fusiform and filamentous organisms in pockets that were irrigated; this coincided with a reduction in the % of bleeding sites. Various patterns of colonization were observed which have been described and may assist in differential dark field (DDF) monitoring of lesions. Bleeding on blunt probing was found to be correlated with a flora dominated by spirochaetes. No other correlations were found over the 10-week period between the other parameters.(ABSTRACT TRUNCATED AT 250 WORDS)