The effects of adjunctive metronidazole plus amoxicillin in the treatment of generalized aggressive periodontitis: a 1-year double-blinded, placebo-controlled, randomized clinical trial.

Objective: To evaluate the clinical effects of the adjunctive use of metronidazole (MTZ) and amoxicillin (AMX) in the treatment of generalized aggressive periodontitis (GAgP).

Methods: Thirty subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with MTZ (400 mg/TID) and AMX (500 mg/TID) for 14 days. Subjects were clinically monitored at baseline, 6 months and 1 year post-therapies.

Results: Both therapies led to a statistically significant improvement in all clinical parameters at 1 year post-therapy (p < 0.05). Subjects receiving MTZ plus AMX exhibited the deepest reductions in mean probing depth (PD) and gain in clinical attachment between baseline and 1 year post-therapy in the full-mouth analysis and in initially intermediate (PD 4-6 mm) and deep (PD ≥ 7 mm) sites (p < 0.01). In addition, the antibiotic group presented lower mean number of residual sites with PD ≥ 5 or 6 mm as well as fewer subjects still presenting nine or more sites with PD ≥ 5 mm or three or more sites with PD ≥ 6 mm at the end of the study period.

Conclusions: The non-surgical treatment of GAgP is markedly improved by the adjunctive use of MTZ+AMX, up to 1 year post-treatment.