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 Miranda TS, Feres M, Perez-Chaparro PJ, Faveri M, Figueiredo LC, Tamashiro NS, Bastos MF, Duarte PM. 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. J Clin Periodontol 2014; 41: 890–899. doi: 10.1111/jcpe.12282. Abstract Aim: To evaluate the clinical and microbiological effects of the use of metronida- zole (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 bio- film samples were analyzed by qPCR for the presence of seven periodontal patho- gens. 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 clini- cal and microbiological outcomes of SRP in the treatment of type 2 diabetic sub- jects with ChP. Tamires Szeremeske Miranda, Magda Feres, Paula Juliana Perez-Chaparro, Marcelo Faveri, Luciene Cristina Figueiredo, Neila Sumie Tamashiro, Marta Ferreira Bastos and Poliana Mendes Duarte Department of Periodontology, Dental Research Division, Guarulhos University, S~ ao Paulo, Brazil Key words: amoxicillin; chronic periodontitis; dental scaling; diabetes mellitus; metronidazole; real-time polymerase chain reaction; root planing Accepted for publication 9 June 2014 Conflict of interest and source of funding statement S~ ao Paulo State Research Foundation (S~ ao Paulo, S~ ao Paulo, Brazil, # 2011/14872-4; 2013/01072-5). The authors declare that they have no conflict of interests. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 890 J Clin Periodontol 2014; 41: 890–899 doi: 10.1111/jcpe.12282