Reduction of two red complex bacteria by sustained-release doxycycline and correlation to improvement in mean pocket...

The objective was to evaluate the effects of an 8.5% sustained-release doxycycline-containing polymer formulation (SRDF) on deep pockets (pocket depth [PD] ≥ 7 mm) in chronic periodontitis. Total bacterial counts were used to estimate the number of viable bacteria present before treatment and for up to 6 months posttreatment.

All sites had PD ≥ 5 mm and bled on probing in 23 subjects who received treatment with SRDF. There was an average of 8.7 teeth or 23 sites for each subject. One deep pocket (≥ 7 mm) in each subject was selected for monitoring. This site was sampled prior to treatment and at 7, 21, 91, and 182 days after SRDF placement. The primary endpoints were changes in the viable counts of two red complex species, Porphyromonas gingivalis and Tannerella forsythia. Secondary endpoints were changes in the number of total anaerobic bacteria recovered and changes in PD.

Relative to baseline, SRDF reduced the proportions of P. gingivalis and T. forsythia by 88% and 99%, respectively, at day 7. At the conclusion of the monitoring period--182 days--P. gingivalis and T. forsythia were present but at 19% to 20% of the pretreatment values. Total anaerobic counts were reduced by 96% at day 7; by 87% at day 21; and by 75% and 68% at days 91 and 182, respectively. Mean PD for the sample sites (initially ≥ 7 mm) was reduced 2 mm by day 21, and this difference persisted throughout the study.

This study demonstrates SRDF has a significant effect, not only statistically but also microbially and clinically, on deep periodontal sites in patients with chronic periodontitis. SRDF significantly reduced the number of red complex bacteria P. gingivalis and T. forsythia, as well as the number of total anaerobic bacteria. By day 21, PD was reduced by 2 mm, and this reduction was maintained for at least 6 months posttherapy.