Effect of Subantimicrobial Dose Doxycycline as an Effective Adjunct to Scaling and Root Planing

Background: This study evaluated the efficacy and safety of a subantimicrobial dose of doxycycline (SDD) in conjunction with scaling and root planing (SRP). Methods: The study was a 9‐month, double masked, randomized, placebo‐controlled, parallel‐group trial. A total of 41 patients with moderate chronic periodontitis who received SRP were randomly allocated to receive either a doxycycline hyclate or a placebo 2 weeks after SRP. Clinical attachment level (CAL), the probing depth (PD), gingival crevicular fluid (GCF) levels, and matrix metalloproteinase (MMP)‐8 and ‐13 levels were measured throughout the study. The effect of SDD in conjunction with SRP on the dynamics of the periodontal microflora was also assessed using dark‐field microscopic and culture analysis. Information on adverse events was collected throughout the study. Results: During the treatment period, per‐patient reductions in PD and CAL were demonstrated for both treatment groups, with a significantly greater reduction for the SDD group. The mean value of per‐patient change in the GCF was much greater for the SDD group. Microbial analysis showed there were a general tendency for cocci, non‐motile rods, and aerobes to increase with increasing treatment duration and a general decreasing tendency for spirochetes, motile rods, and anaerobes and black pigmented bacteria in both treatment groups, but no significant difference between the groups. The MMP‐8 and ‐13 levels of the SDD group gradually reduced with time, and the mean perpatient average was significantly higher than in the placebo group. The adverse events in the SDD group were similar to those in the placebo group. Conclusion: This study suggests that a submicrobial dose of doxycycline as an adjunct therapy with SRP might be safe and effective in the long‐term management of chronic periodontitis. J Periodontol 2004;75:1500‐1508.