Metronidazole and amoxicillin as adjuncts to scaling and root planing for the treatment of type 2 diabetic subjects with periodontitis: 1-year outcomes of a randomized placebo-controlled clinical trial

Aim: To evaluate the clinical and microbiological effects of the use of metronidazole (MTZ) + amoxicillin (AMX) as adjuncts to scaling and root planing (SRP) for the treatment of chronic periodontitis (ChP) in type 2 diabetic subjects. Material and Methods: Fifty-eight type 2 diabetic subjects (n = 29/group) with generalized ChP were randomly assigned to receive SRP alone or with MTZ [ 400 mg/thrice a day (TID)]+AMX (500 mg/TID) for 14 days. Subgingival biofilm samples were analyzed by qPCR for the presence of seven periodontal pathogens. Subjects were monitored at baseline, 3, 6 and 12 months post-therapies. Results: The group receiving SRP+MTZ+AMX presented greater mean probing depth (PD) reduction and clinical attachment gain, a lower number of sites with PD >= 5 mm (primary outcome variable) and a reduced number of subjects with = 9 of these residual pockets than the control group at 1-year post-therapy (p < 0.05). The antibiotic-treated group also presented reduced levels and greater decreases of the three red complex species, Eubacterium nodatum and Prevotella intermedia, compared to the control group at 1 year (p < 0.05). Conclusions: The adjunctive use of MTZ+AMX significantly improved the clinical and microbiological outcomes of SRP in the treatment of type 2 diabetic subjects with ChP.