Amoxicillin and Metronidazole as an Adjunct to Full-Mouth Scaling and Root Planing of Chronic Periodontitis

Background: It has been suggested that scaling and root planing of all pockets within a few hours and chlorhexidine treatments (full-mouth disinfection) may reduce the need for supplementary therapies. The aim of this study was to evaluate the clinical benefit of amoxicillin and metronidazole administered immediately after completion of full-mouth periodontal debridement in patients with chronic periodontitis. Methods: This was a single-center, double-masked, placebo-controlled, randomized longitudinal study of 6 months' duration. Fifty-one patients received full-mouth periodontal debridement, performed within 48 hours. Twenty-five subjects received metronidazole, 500 mg, and amoxicillin, 375 mg, three times a day for 7 days; 26 subjects received a placebo. Results: Forty-seven patients could be followed up to month 6. No differences in clinical parameters were noted before treatment. The overall mean probing depth decreased from 4.3 +/- 0.4 mm to 3.0 +/- 0.2 mm in the test group and from 4.4 +/- 0.4 mm to 3.1 +/- 0.3 mm in the control group (P=0.05, difference between groups). More importantly, test subjects had a significantly lower mean number of persisting pockets >4 mm and bleeding on probing that required further treatment (P=0.005): 6 months after full-mouth debridement plus antibiotics, only 0.4 +/- 0.8 persisting pockets were still present, whereas 3.0 4.3 persisting pockets were still present in the control group. The protective risk of the antibiotics for having more than one pocket deeper than 4 mm and bleeding on probing per subject after 6 months was 8.85. Conclusion: Systemic metronidazole and amoxicillin significantly improved the 6-month clinical outcomes of full-mouth non-surgical periodontal debridement, thus significantly reducing the need for additional therapy. J Periodontol 2009;80:364-371.