Background: Subantimicrobial-dose doxycycline (SDD) is widely used as an adjunctive treatment to scaling and root planing (SRP), but its long-term effectiveness remains controversial. The purpose of this systematic review was to assess the actual evidence of the effectiveness of SRP + SDD compared to SRP + placebo in the treatment of chronic periodontitis.
Methods: A literature search of electronic databases was performed for articles published through November 1, 2010. Several dental journals were screened during the manual search, and authors were contacted for missing information. The systematic review and meta-analysis were conducted according to the Quality of Reporting of Meta-Analyses statement and recommendations of the Cochrane Collaboration. The methodologic quality of the studies was determined via a Consolidated Standards of Reporting Trials-based assessment. Clinical attachment levels, probing depths, plaque and gingival indices, and gingival crevicular fluid levels were compared between baseline and the end of follow-up. Data were extracted and pooled using a random-effect model. The weighted mean difference was reported with the 95% confidence interval. Heterogeneity was assessed using the χ(2)-based Q-statistic method and I(2) measurement. P <0.05 was considered statistically significant.
Results: After applying inclusion and exclusion criteria, three randomized placebo-controlled clinical trials were entered into the meta-analysis. These studies had similar treatment designs, SDD dosage regimens (20 mg twice daily for 3 months), and post-treatment follow-up lengths (9 months). Significant differences were observed for all investigated clinical parameters in favor of the SRP + SDD group.
Conclusion: The meta-analysis results seemed to support the long-term effectiveness of adjunctive SDD therapy; however, future studies are needed to confirm these findings.