Clinical and Microbiologic Effects of Subgingivally Delivered 0.5% Azithromycin in the Treatment of Chronic Periodontitis

Background: Recent developments suggest that the local delivery of antimicrobials into periodontal pockets can improve periodontal health. The present study was undertaken to investigate the clinical and microbiologic effectiveness of azithromycin (AZM) at 0.5% concentration in an indigenously prepared bioabsorbable controlled-release gel as an adjunct to non-surgical mechanical therapy in the treatment of chronic periodontitis. Methods: Eighty patients were categorized into two treatment groups: scaling and root planing (SRP) only (group 1) and SRP plus 0.5% AZM (group 2). Clinical parameters were recorded at baseline and 1, 2, and 3 months; they included modified gingival index, modified sulcus bleeding index, probing depth (PD), and clinical attachment level (CAL). At baseline and 6 and 12 weeks, microbiologic assessment was done of the percentage of morphologically different microorganisms (coccoid cells, others [straight rods, filaments, and fusiforms], motile rods, and spirochetes) using darkfield microscopy. The mean concentration of 0.5% AZM in gingival crevicular fluid was estimated by reverse phase high performance liquid chromatography. Results: Both therapies resulted in significant improvements. Mean PD reduction from baseline to 3 months was 2.13 +/- 0.35 mm and 2.53 +/- 0.52 in groups 1 and 2, respectively. Mean CAL gain from baseline to 3 months was 0.60 +/- 0.63 mm and 1.07 +/- 0.70 mm in groups 1 and 2, respectively. All microbiologic categories showed significant improvement in both groups, with greater improvement in the test group. The mean concentration of AZM at all observed periods (baseline to 28 days) provided sufficient antimicrobial activity (>2 mu g/ml) and fulfilled the conditions for a controlled-release device. Conclusion: Although both treatment strategies seemed to benefit the patients, the adjunctive use of 0.5% AZM as a controlled drug-delivery system enhanced the clinical and microbiologic results as shown by the intergroup comparison. J Periodontol 2008;79:2125-2135.