Different antibiotic protocols in the treatment of severe chronic periodontitis: A 1-year randomized trial

To evaluate the clinical effects of different dosages of metronidazole (MTZ) and durations of MTZ + amoxicillin (AMX) in the treatment of generalized chronic periodontitis (GChP).

Subjects with severe GChP were randomly assigned to receive scaling and root planing (SRP)-only, or combined with 250 or 400 mg of MTZ + AMX (500 mg) thrice a day (TID), for 7 or 14 days. Subjects were monitored for 1 year.

One hundred and nine subjects were enrolled. At 1 year, 61.9% and 63.6% of the subjects receiving AMX + 250 or 400 mg of MTZ for 14 days, respectively, reached the clinical endpoint for treatment (≤4 sites with probing depth ≥5 mm), against 31.8% of those taking 250 or 400 mg of MTZ for 7 days (p < .05) and 13.6% of those receiving SRP-only (p < .05). Fourteen days of MTZ + AMX was the only significant predictor of subjects reaching the clinical endpoint at 1 year (OR, 5.26; 95% CI, 2.3-12.1, p = .0000). The frequency of adverse events did not differ among treatment groups (p > .05).

The adjunctive use of 400 or 250 mg of MTZ plus 500 mg of AMX/TID/14 days offers statistically significant and clinically relevant benefits over those achieved with SRP alone in the treatment of severe GChP. The added benefits of the 7-days regimen in this population were less evident. (ClinicalTrials.gov NCT02735395).