Materials and Methods: Investigation’s design was a double-blind, placebo-controlled, multi-center randomized controlled trial over a 38-month period. We hypothesized that adjunctive antibiotic therapy significantly reduces (Δ50%) the occurrence of further attachment loss compared to subgingival debridement alone. The primary objective efficacy variable was the percentage of sites with a loss of clinical attachment ≥ 1.3 mm over the 24-month follow-up period. Key secondary variables were additional periodontal, microbiological and psychological parameters.
Results: For eligibility 3261 patients were screened, 542 patients were recruited, and finally 406 patients completed the trial in December 2011 (power calculation revealed 350 completed cases).
Conclusions: The experiences from this trial, considering demands and suggestions for clinical research from systematic reviews, showed that realization is possible. Those study designs are highly labor- and cost-intensive. Public funding will be even more important in the future to answer clinical questions on a generalizable population level.