Adjunctive Systemic Amoxicillin and Metronidazole with Scaling and Root Planing

Objectives: The present clinical trial was performed to study the effect of systemic administration of metronidazole and amoxicillin as an adjunct to mechanical therapy in patients with modarate to severe chronic periodontitis. Methods: Altogether 50 adult patients with untreated periodontitis were randomly assigned to receive full-mouth scaling and root planing with systemic metronidazole plus amoxicillin (T-group) or scaling and root planing with placebo (P-group). Clinical measurements including probing depth (PD), clinical attachment level (CAL), plaque index (PI) and bleeding index (BI) were taken at baseline and 6 to 8 weeks after therapy. The deepest pocket was selected for microbiological testing. Patients received coded study medication of either 500mg amoxicillin in combination with 250mg metronidazole or similar appearnce placebo, every 8 hours for the following 7 days. Results: There was a significant change in PD(p=0.0001), CAL (p=0.00001), PI (p=0.029) and BI( p=0.034) in the T-group as compared to the P-group after therapy . parallel to the clinical changes, treatment reduced the number of A.a , P.g and P.i compared with baseline in the T-group. This reduction was significant(p=0.003, 0.021, 0.0001, respectively), but in P-group only p.i colony count reduced significantly (p=0.0001). Only P.i showed significant difference between two groups at the end of the study(p=0.026). After therapy there was a significant difference between the T-and P-group in the number of patients negative for A.actinomycetemcomitans, P.gingivalis and P.intermedia (P-value = 0.033). Conclusions: The significant differences between T-and P-groups, in line with other studies, support the considerable adjunctive benefits to SRP of amoxicillin and metronidazole combined in the treatment of modarate to severe chronic periodontitis.