Initial effect of controlled release chlorhexidine on subigingival microorganisms

Background: Little or no data exist on the ability of subgingival application of PerioChip(R) (2.5 mg chlorhexidine gluconate in a biodegradable chip; Astra Pharmaceuticals, Westborough, MA, USA) to suppress periodontopathic microorganisms. The present study compared the subgingival microbiota of periodontitis sites receiving the chlorhexidine chip plus scaling and root planing (Sc/Rp) or Sc/Rp alone. Methods: Seven males and six females, mean age 49 years, with moderate to advanced periodontitis participated in the study. In each patient, two bilateral pockets probing 6-7 mm were randomly assigned to treatment by chlorhexidine chip + Sc/Rp, or by Sc/Rp alone. Subgingival placement of chlorhexidine chips was carried out according to the manufacturer's instructions. Sc/Rp was performed with hand instruments for at least 10 min in each study tooth. Subgingival samples were collected by paper-points at baseline, at 2 weeks and at 4 weeks posttreatment. Anaerobic culture methods were used for microbial isolation and identification. The microbiologic examination was carried out blindly. Microbiological data were evaluated by a repeated measures analysis of variance. Results: No statistical difference was found in total colony counts between subgingival sites treated with chlorhexidine chip + Sc/Rp and those treated with Sc/Rp alone. Also, the percentage of major periodontal pathogens (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Bacteroides forsythus) and the percentage of total periodontal pathogens (A. actinomycetemcomitans, P. gingivalis, B. forsythus, Prevotella intermedia-group, Fusobacterium, Eubacterium, Campylobacter rectus, Peptostreptococcus micros, Eikenella corrodens, enteric rods) were not significantly different between the chlorhexidine chip + Sc/Rp group and the Sc/Rp group. At baseline, A. actinomycetemcomitans was recovered from 4 chlorhexidine chip + Sc/Rp sites and 2 Sc/Rp sites, P. gingivalis from 5 chlorhexidine chip + Sc/Rp sites and 4 Sc/Rp sites, and B. forsythus from 9 chlorhexidine chip + Sc/Rp and 7 Sc/Rp sites. At 4 weeks, A. actinomycetemcomitans was detected in 2 chlorhexidine chip + Sc/Rp sites but not in any site P. gingivalis in 2 chlorhexidine chip + Sc/Rp sites but not in any receiving Sc/Rp, Sc/Rp site, and B. forsythus in I chlorhexidine chip + Sc/Rp and in 2 Sc/Rp sites. Conclusion: The present data obtained from bilateral periodontitis lesions of 13 adults suggest that chlorhexidine chip treatment of adult periodontitis lesions provides little or no additional antimicrobial benefits compared to thorough Sc/Rp alone.