ObjectivesLocally used doxycycline has been shown to concentrate in crevicular fluid and demonstrates a wide spectrum of activity against the periodontal pathogens. The aim of the present clinical study was to evaluate the efficacy of doxycyline hyclate 10% as an adjunct to scaling and root planing in the treatment of chronic periodontitis.Material and Methods60 systemically healthy, chronic periodontitis patients were included in the study. Randomized clinical trial was performed over the 6 month period. Test group was treated by scaling and root planing followed by local delivery of doxycycline hyclate 10%, while the control group was treated by scaling and root planing along with placebo.ResultsSignificantly greater (P < 0.001) reduction in the mean probing pocket depth was demonstrated in the test group (3.03 ± 0.92 mm) when compared with the control group (2.3 ± 0.65 mm). When the differences in clinical attachment level gain for the test group (2.0 ± 0.64 mm) versus control group (1.13 ± 1.07 mm) were analyzed by Student's unpaired t-test, test group showed statistically greater clinical attachment level gain (0.87 ± 0.22 mm, P < 0.001).ConclusionsFrom the analysis of the results it can be concluded that the use of doxycyline hyclate 10% as an adjunct to scaling and root planing provides more favourable and statistically significant (P < 0.001) reductions in probing pocket depth and gains in clinical attachment level compared to scaling and root planing alone.