Clinical and microbiological effects of azithromycin in the treatment of generalized chronic periodontitis: a randomized placebo-controlled clinical trial

Aim: To evaluate the effects of systemic azithromycin (AZM) as an adjunct to scaling and root planing (SRP) in the treatment of generalized chronic periodontitis (ChP). Methods: Forty subjects were randomly assigned to receive SRP alone or combined with AZM (500 mg/day) for 5 days (n = 20/group). Clinical and microbiological examinations were performed at baseline, 6 months and 1-year post-SRP. Nine plaque samples per subject were analysed by checkerboard DNA-DNA hybridization for 40 bacterial species. Differences between groups were assessed using the Mann-Whitney test and over time using Friedman and Dunn's tests. Results: No statistically significant differences were observed between groups for any parameters evaluated at 1-year post-treatments. Both therapies equally reduced the mean probing depth (PD) (SRP: 3.83 +/- 1.92, AZM: 3.45 +/- 1.74) and improved the mean clinical attachment (SRP: 2.35 +/- 1.70, AZM: 2.68 +/- 1.76) in sites with initial PD >= 7 mm (primary outcome variable) between baseline and 1 year. The mean counts and proportions of several periodontal pathogens were reduced, and those of host-beneficial species were increased after treatments. Nonetheless, an important recolonization with red complex species was observed in both groups over the course of the study. Conclusion: The data of the present study suggest no adjunctive benefit of AZM in the treatment of generalized ChP.