Microbiological evaluation of adjunctive systemic and local tetracycline administration combined with scaling and root planing in the treatment of chronic periodontitis

Correspondence to : Ana Paula V. Colombo R. Gal. Dionísio, 60 apt. 804 – Humaitá CEP: 22271-050 Rio de Janeiro, RJ, Brazil Email: [email protected] Abstract The purpose of this study was to evaluate the microbiological changes in the subgingival biofilm resulting from systemic or local tetracycline therapy associated with scaling and root planing (SRP) in chronic periodontitis. Thirty patients with chronic periodontitis were randomly assigned to 3 groups: SRP + 500 mg of systemic tetracycline twice/day for 14 days; SRP alone and SRP + tetracycline fibers at 4 selected sites for 10 days. Subgingival plaque samples were obtained from 4 selected sites with probing pocket depths of 6 10 mm in each subject at baseline, 1 week, 3 and 6 months post-therapy. The presence and levels of 31 subgingival species distributed into microbial complexes were determined using the checkerboard technique. Significant microbiological changes within and among groups were sought using the Friedman and Kruskal-Wallis tests. Most of the microbial complexes decreased in prevalence and levels at 1 week and 3 months, but tended to return to baseline levels at 6 months after treatment. Beneficial species were reduced over time in subjects who received SRP only, however were increased or maintained in the patients treated with local and systemic tetracycline. Moreover, these groups showed a significant reduction (p < 0.01) in the prevalence of the “red complex” species as compared to the control. Likewise, A. actinomycetemcomitans was more decresed in both tetracycline groups. In chronic periodontitis, local and systemic tetracycline therapy significantly reduced the prevalence of some periodontal pathogens and favored the increase of beneficial species for at least 6 months after treatment.