Abstract

Aim: Adjunctive systemic antibiotics may improve the outcome of mechanical periodontitis therapy. Systematic reviews revealed the lack of sufficient data and well-designed clinical trials about the efficacy of this adjunct to periodontal therapy. This protocol was designed to address demands and suggestions for further clinical trials made by recent EFP reviews.

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.

Keywords: Amoxicillin, metronidazole, RCT, periodontitis, trial design, scaling, clinically significant additional effect, multicenter study, placebo-controlled clinical study, oral health-related quality of life.