A double-masked Randomized Clinical Trial (RCT) comparing four periodontitis treatment strategies: 5-year clinical results

J Clin Periodontol. 2017 Oct;44(10):1029-1038. doi: 10.1111/jcpe.12793. Epub 2017 Sep 15.


Aim: To test the hypothesis of no difference in the 5-year clinical outcome of therapy between groups of patients treated with conventional over-weeks scaling and root planing or same-day full-mouth-disinfection, with or without adjunctive metronidazole (MTZ).

Materials and methods: Following a three-month oral hygiene phase, 184 periodontitis patients were randomly allocated to one of four treatment regimens (1) full-mouth disinfection (FDIS)+ MTZ, (2) FDIS +placebo, (3) scaling and root planing+ MTZ and (4) scaling and root planing+placebo. Following active treatment, patients received biannual maintenance; 161 patients completed the five-year follow-up maintenance and examination, where clinical attachment level (CAL), probing pocket depth (PPD), presence of plaque and bleeding were registered.

Results: Metronidazole increased the highest CAL recording statistically insignificantly by an average of 0.17 mm while FDIS decreased it by an average of 0.12 mm. The corresponding values for the highest PPD were 0.00 and 0.05 mm, respectively.

Conclusion: While single-level analyses showed statistically significant differences, they could not be confirmed with more appropriate analyses and were too small to recommend MTZ, with its risk of patient side effects and environmental consequences, for the treatment of patients with severe periodontitis.

Trial registration: ClinicalTrials.gov NCT01318928.

Keywords: antibiotics; full-mouth disinfection; metronidazole; periodontal disease; scaling and root planing.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Anti-Infective Agents, Local / therapeutic use*
  • Chlorhexidine / therapeutic use*
  • Dental Plaque Index
  • Dental Scaling*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Metronidazole / therapeutic use*
  • Middle Aged
  • Periodontal Index
  • Periodontitis / therapy*
  • Root Planing*
  • Treatment Outcome


  • Anti-Infective Agents, Local
  • Metronidazole
  • Chlorhexidine

Associated data

  • ClinicalTrials.gov/NCT01318928