Amoxicillin and metronidazole as adjunct to full-mouth non-surgical periodontal treatment

Objectives: To evaluate the clinical benefit of amoxicillin and metronidazole administered immediately after completion of full-mouth periodontal debridement in patients with chronic periodontitis.

Methods: Single centre, double blind, placebo controlled, randomized longitudinal study of 6 months duration. 40 patients received full-mouth periodontal debridement, performed within 48 hours. Using a parallel design, 20 subjects then received 500 mg metronidazole and 375 mg amoxicillin 3/d for 7 days (test group) and 20 received a placebo (control group). A total of 3126 sites (6 per tooth) were clinically monitored at baseline, at month 3 and 6 by a blinded, independent investigator.

Results: No differences in clinical parameters were noted before treatment. The over-all mean PPD was 4.3±0.38 mm, clinical attachment loss amounted to 5.4±0.6 mm, and 64% sites were bleeding on probing. Six months after treatment, mean PPD was significantly lower in the test than the control subjects (2.9±0.2 mm vs. 3.1±0.3 mm, p=0.027). More importantly, test subjects also had a significantly lower mean number of persisting pockets of >4mm PPD and bleeding upon probing, needing further treatment (M3: p=0.028; M6: p=0.003): three months after full-mouth debridement plus antibiotics, only 1.3±2.2 persisting pockets were noted per subject, and only 0.4±0.6 at month 6, whereas in the control group 4.4±2.2 and 3.7±4.6 persisting pockets were still present, respectively.

Conclusion: Systemic metronidazole and amoxicillin significantly improved the 6 months clinical outcomes of full mouth non-surgical periodontal debridement, thus significantly reducing the need for additional therapy.